Patent Application
20250000444
Knee arthroplasty involves replacement of articular surfaces of the knee joint to restore function. An important part of a successful knee arthroplasty procedure involves evaluating the soft tissue or ligaments of the knee joint to ensure proper stability, laxity, stiffness, and/or range of motion of the joint. To date, many surgeons still prefer to assess the knee joint ligaments using traditional, manual methods and devices.
One known device for evaluating the knee joint is a knee distractor which has one or more upper paddles for engaging the femur and a lower paddle for engaging the tibia. The paddles move apart to provide a measurement related to the force or spacing between the joint. However, conventional distractors have many shortcomings.
Conventional distractors have limited adjustability. For example, conventional distractors can be “one-size-fits-all” and not configured to accommodate various sized bones of the knee joint. In attempt to accommodate larger sized bones, these types of distractors require a bulky size, which increases the difficulty of inserting the distractor into the knee. Some conventional distractors configurations are limited to only evaluate either the left knee or the right knee, but not both. For example, some conventional distractors include curved paddles to avoid impingement with the patellar tendon. However, the curved paddles may not be removable, and hence, are designed to circumvent the patellar tendon for only the left or right knee. To circumvent the patellar tendon on both knees, some conventional designs require the curved paddles to be removed and replaced with a different (oppositely curved) set of paddles. Replacing these components prolongs the evaluation process (during which the patient is under anesthesia) and increases complexity and cost.
Conventional distractors are at risk of slipping out of the knee joint during the evaluation process. Slippage can cause potential damage to the knee joint, inaccurate measurements, and inconvenience to the surgeon. This issue is particularly prominent with mid-resection workflows, wherein the tibia is resected prior to the evaluation. The rigid, minimally adjustable, configurations of conventional distractors have limited contact coverage of the paddle with the corresponding bone and, in turn, increases susceptibility to slippage. Alternatively, conventional distractors require the lower paddle to be invasively fastened to the resected tibial plane to reduce slippage. Fastening the lower paddle to the resected tibia adds additional surgical steps and trauma to the bone.
Conventional distractors also are not optimized for cleaning or sterilization. Some distractors include exposed parts, such as springs, actuators, or measurement devices that require thorough sterilization and are susceptible to damage from the sterilization process. Time consuming disassembly of components of the distractor may be needed for cleaning or other purposes. The sterilized components are at risk of failure or wear and tear.
Most conventional distractors are not motorized and do not utilize the advantages of computer aid, such as surgical navigation and/or clinical applications. Therefore, the surgeon often must rely on their subjective knowledge and skill to predict the state of the joint ligaments. In turn, the joint evaluation and surgical outcome can be sub-optimal with conventional distractors. One particularly challenging part of the knee evaluation process involves determining the optimal laxity of the knee joint required to enable the knee to reach full extension. Distracting the knee at 0 degrees (full extension) will likely produce inaccurate measurements due to posterior capsule tightness. To assess the tension of the knee at full extension, surgeons typically use a trial-and-error process in which the surgeon inserts the manual distractor in a mid-flexion pose and uses an educated guess to set the tension of the distractor. The knee is then moved towards full extension. If the knee is unable to reach full extension, the surgeon must reset the tension of the distractor and repeat the assessment. Such a process prolongs the evaluation process, produces sub-optimal results, and is inconvenient to the surgeon.
This Summary introduces a selection of concepts in a simplified form that are further described below in the Detailed Description below. This Summary is not intended to limit the scope of the claimed subject matter nor identify key features or essential features of the claimed subject matter.
According to a first aspect, a tensor is provided that is motorized and wherein the tensor is configured to operate in a force control mode to apply forces to an anatomical joint until a predetermined force is reached; capture a plurality of force-displacement data pairs as a result of the forces applied by the tensor in the force control mode; and operate in a displacement control mode whereby a displacement of the tensor is progressively decreased according to displacements from the plurality of force-displacement data pairs.
According to a second aspect, a method is provided of operating a tensor that is motorized, the method comprising: operating the tensor in a force control mode for applying forces to an anatomical joint until a predetermined force is reached; capturing a plurality of force-displacement data pairs resulting from the tensor applying forces in the force control mode; and operating the tensor in a displacement control mode by progressively decreasing a displacement of the tensor according to displacements from the plurality of force-displacement data pairs.
According to a third aspect, a surgical system is provided which is configured to evaluate an anatomical joint, the surgical system comprising: a tensor that is motorized and configured to operate in a force control mode and a displacement control mode; and a control system configured to control the tensor and being configured to: control the tensor in the force control mode to apply forces to the anatomical joint until a predetermined force is reached; capture a plurality of force-displacement data pairs from the tensor as a result of the forces applied by the tensor in the force control mode; and control the tensor in the displacement control mode whereby a displacement of the tensor is progressively decreased according to displacements from the plurality of force-displacement data pairs.
According to a fourth aspect, a method is provided of utilizing a surgical system for evaluating an anatomical joint, the surgical system comprising a tensor that is motorized and configured to operate in a force control mode and a displacement control mode, and a control system configured to control the tensor, the method comprising: controlling, with the control system, the tensor in the force control mode for applying forces to the anatomical joint until a predetermined force is reached; capturing, with the control system, a plurality of force-displacement data pairs from the tensor resulting from the tensor applying forces in the force control mode; and controlling, with the control system, the tensor in the displacement control mode by progressively decreasing a displacement of the tensor according to displacements from the plurality of force-displacement data pairs.
According to a fifth aspect, a surgical system is provided which is configured to evaluate a knee joint, the surgical system comprising: a tensor that is motorized and configured to operate in a force control mode and a displacement control mode; and a control system configured to control the tensor and being configured to: control the tensor in the force control mode to apply forces to the knee joint until a predetermined force is reached; capture a plurality of force-displacement data pairs from the tensor as a result of the forces applied by the tensor in the force control mode; and control the tensor to switch from the force control mode to the displacement control mode and control the tensor in the displacement control mode to perform an extension test whereby a displacement of the tensor is progressively decreased according to displacements from the plurality of force-displacement data pairs until the knee joint can reach an acceptable full extension pose during, or after completion of, the extension test.
According to a sixth aspect, a method is provided of utilizing a surgical system for evaluating a knee joint, the surgical system comprising a tensor that is motorized and configured to operate in a force control mode and a displacement control mode, and a control system configured to control the tensor, the method comprising: controlling, with the control system, the tensor in the force control mode for applying forces to the knee joint until a predetermined force is reached; capturing, with the control system, a plurality of force-displacement data pairs from the tensor resulting from the tensor applying forces in the force control mode; and controlling, with the control system, the tensor for switching from the force control mode to the displacement control mode and controlling the tensor in the displacement control mode for performing an extension test by progressively decreasing a displacement of the tensor according to displacements from the plurality of force-displacement data pairs until the knee joint can reach an acceptable full extension pose during, or after completion of, the extension test.
According to a seventh aspect, an orthopedic tensor is provided, comprising: a body; an upper paddle movable relative to the body and configured to engage a first bone of an anatomical joint; a lower paddle coupled to the body and configured to engage a second bone of the anatomical joint; a drive assembly disposed within the body and comprising an electric motor, and a displacement mechanism coupled between the electric motor and the upper paddle, and wherein the electric motor is configured to move the displacement mechanism to linearly displace the upper paddle relative to the lower paddle; and a sensor configured to sense force applied to the upper paddle, wherein the sensor is located in the displacement mechanism.
According to an eighth aspect, an orthopedic tensor is provided, comprising: a body; an upper paddle movable relative to the body and configured to engage a first bone of an anatomical joint; a lower paddle coupled to the body and configured to engage a second bone of the anatomical joint; a drive assembly coupled to the body and comprising an electric motor, and a displacement mechanism coupled between the electric motor and one, or both of, the upper paddle and the lower paddle, and wherein the electric motor is configured to move the displacement mechanism to displace the upper paddle and/or the upper paddle relative to one another; and a sensor configured to sense force applied to one, or both of, the upper paddle and the lower paddle, wherein the sensor is configured to move in accordance with movement of the displacement mechanism.
According to a ninth aspect, an orthopedic tensor is provided comprising: a first body; a first set of paddles coupled to the first body, the first set of paddles comprising a first upper paddle movable relative to the first body and configured to engage a first bone of an anatomical joint and a first lower paddle configured to engage a second bone of the anatomical joint; a second body separate from the first body; a second set of paddles coupled to the second body, the second set of paddles comprising a second upper paddle moveable relative to the second body and configured to engage the first bone of the anatomical joint and a second lower paddle configured to engage the second bone of the anatomical joint; and a retainer configured to hold the first body and the second body relative to one another, wherein the first body is configured to rotate within the retainer to enable rotational adjustment of the first set of paddles, and wherein the second body is configured to rotate within the retainer to enable rotational adjustment of the second set of paddles; and wherein a locking mechanism is coupled to the retainer and configured to be actuated to rotationally lock one, or both, of the first body and the second body relative to the retainer.
According to a tenth aspect, a retainer is provided for an orthopedic tensor, the retainer defining a first sleeve configured to receive a first body of the tensor and a second sleeve configured to receive a second body of the tensor, wherein the retainer enables the first body to rotate within the first sleeve to enable rotational adjustment of the first set of paddles, and enables the second body to rotate within the second sleeve to enable rotational adjustment of the second set of paddles, and wherein a locking mechanism is coupled to the retainer and configured to rotationally lock one, or both, of the first body and the second body relative to the retainer.
According to an eleventh aspect, an orthopedic tensor is provided comprising: a first body; a first set of paddles coupled to the first body, the first set of paddles comprising a first upper paddle movable relative to the first body and configured to engage a first bone of an anatomical joint and a first lower paddle configured to engage a second bone of the anatomical joint; a second body separate from the first body; a second set of paddles coupled to the second body, the second set of paddles comprising a second upper paddle moveable relative to the second body and configured to engage the first bone of the anatomical joint and a second lower paddle configured to engage the second bone of the anatomical joint; and a link portion coupled between the first body and the second body, the link portion comprising one or more joints configured to enable adjustment of the first body and the second body so as to enable adjustment of the first set of paddles and the second set of paddles; wherein a locking mechanism is coupled to the link portion and is configured to be actuated to lock the one or more joints so as to lock the first body and the second body relative to one another.
According to a twelfth aspect, a retainer is provided for an orthopedic tensor, the retainer defining a first sleeve configured to receive a first body of the tensor and a second sleeve configured to receive a second body of the tensor, wherein the retainer comprises a link portion coupled between the first sleeve and the second sleeve, the link portion comprising one or more joints configured to enable adjustment of the first body and the second body so as to enable adjustment of the first set of paddles and the second set of paddles; wherein a locking mechanism is coupled to the link portion and is configured to be actuated to lock the one or more joints so as to lock the first body and the second body relative to one another.
According to a thirteenth aspect, an assembly is provided for evaluating an anatomical joint which comprises a first bone and a second bone, the assembly comprising: an orthopedic tensor comprising a lower paddle and an upper paddle, and a drive assembly configured to move the upper paddle relative to the lower paddle; and an auxiliary paddle that is configured to be inserted between and captured by the upper paddle and the lower paddle, wherein the auxiliary paddle comprises a distal portion that extends beyond a distal end of each of the upper paddle and lower paddle after the auxiliary paddle is captured, wherein the distal portion is configured to contact the first and second bones of the anatomical joint.
According to a fourteenth aspect, a method is provided of utilizing an assembly for evaluating an anatomical joint which comprises a first bone and a second bone, the assembly comprising an orthopedic tensor comprising a lower paddle and an upper paddle, and a drive assembly to move the upper paddle relative to the lower paddle, and an auxiliary paddle comprising a distal portion, the method comprising: inserting the auxiliary paddle between the upper paddle and the lower paddle; controlling the orthopedic tensor to move the upper paddle towards the lower paddle with the auxiliary paddle inserted therebetween; and capturing the auxiliary paddle between the upper paddle and lower paddle such that the distal portion of the auxiliary paddle is extending beyond a distal end of each of the upper paddle and lower paddle; and utilizing the distal portion of the auxiliary paddle to contact the first and second bones of the anatomical joint.
According to a fifteenth aspect, an auxiliary paddle is provided that is configured to be used with an orthopedic tensor for evaluating an anatomical joint which comprises a first bone and a second bone, the orthopedic tensor comprising a lower paddle and an upper paddle, and a drive assembly to move the upper paddle relative to the lower paddle, wherein the auxiliary paddle comprises: a body that is configured to be inserted between and captured by the upper paddle and lower paddle of the orthopedic tensor; and a distal portion coupled to body and being configured to extend beyond a distal end of each of the upper paddle and lower paddle, wherein the distal portion is configured to contact the first and second bones of the anatomical joint.
According to a sixteenth aspect, an auxiliary paddle is provided that is configured to be used with an orthopedic tensor, wherein the auxiliary paddle comprises: a body; a distal portion coupled to body and configured to contact non-resected surfaces of a first bone and second bone of an anatomical joint; and a pivot being provided on the body and/or coupled to the distal portion.
According to a seventeenth aspect, an orthopedic tensor is provided comprising: a body; an upper paddle coupled to the body and configured to engage a first bone of an anatomical joint; a lower paddle coupled to the body and configured to engage a second bone of the anatomical joint; and a load cell configured to sense force applied to one of the upper paddle or lower paddle, wherein the load cell is incorporated into the one of the upper paddle or lower paddle.
According to an eighteenth aspect, a paddle is provided for an orthopedic tensor, the paddle comprising: a paddle base that is configured to removably attach to the orthopedic tensor; a paddle surface that extends from the base and is configured to engage a bone of the anatomical joint; and a load cell configured to sense force applied to the paddle, wherein the load cell is incorporated into the paddle base or the paddle surface.
According to a nineteenth aspect, an orthopedic tensor assembly is provided comprising: first body; a first set of paddles coupled to the first body, the first set of paddles comprising a first upper paddle movable relative to the first body and configured to engage a first bone of an anatomical joint and a first lower paddle configured to engage a second bone of the anatomical joint; a second body coupled to the first body; a second set of paddles coupled to the second body, the second set of paddles comprising a second upper paddle moveable relative to the second body and configured to engage the first bone of the anatomical joint and a second lower paddle configured to engage the second bone of the anatomical joint; and a spacer configured to be coupled to a paddle of the first or second set of paddles.
According to a twentieth aspect, a surgical system is provided that is configured to evaluate a knee joint, the surgical system comprising: a tensor comprising a body supporting: a first paddle and a second paddle that are configured to interact with the knee joint; and a sensing system configured to sense: a force applied to at least one of the first and second paddles, and/or a displacement between the first and second paddles; and a control system coupled to the tensor being configured to: obtain a sensed value of force and/or displacement from the sensing system; utilize the sensed value to predict a deflection of one or both of the first paddle and the second paddle; and update the sensed value based on the predicted deflection.
Computer-implemented methods and/or computer program products (or non-transitory computer readable mediums) are provided for operating, or that are configured to operate, any surgical system, tensor, assembly, or paddle of any aspect.
Any of the above aspects can be combined in part, or in whole, with any other aspect. Any of the aspects above can be combined in part, or in whole, with any of the following implementations:
The control system can control the tensor in the force control mode to apply forces to the knee joint until the predetermined force is reached when a current pose of the knee joint is at a first acceptable flexion pose. The knee joint includes a femur and a tibia, and the surgical system can include a localizer and a display device, and wherein the control system can: track a pose of the femur and a pose of the tibia with the localizer; control the display device to provide visual guidance to aid in placing the current pose of the knee joint in the first acceptable flexion pose; capture, with the localizer, the current pose of the knee joint relative to the first acceptable flexion pose; and/or control the display device to provide a visual confirmation in response to the current pose of the knee joint being at the first acceptable flexion pose. The first acceptable flexion pose can be a value between 2-15 degrees of knee joint flexion, such as 10 degrees. The control system can control the display device to provide a visual representation of a current pose of the knee joint based on the poses of the femur and the tibia tracked by the localizer. The control system can measure a gap of the knee joint based on the pose of the femur and the tibia tracked by the localizer. The control system can capture, with the localizer, the current pose of the knee joint relative to the acceptable full extension pose and/or control the display device to provide a visual confirmation in response to the current pose of the knee joint being at the acceptable full extension pose. The acceptable full extension pose can be a value from 0-2 degrees of knee joint flexion, such as 0 degrees. The control system can generate a look-up table based on the plurality of force-displacement data pairs captured from the tensor and/or perform the extension test according to displacements from the look-up table. The control system can capture a target displacement of the tensor at a time when the predetermined force was reached, the target displacement being indicative of a target gap of the knee joint. Prior to performing the extension test, the control system can control the tensor in the displacement control mode to place the tensor at the target displacement and/or perform the extension test by progressively decreasing the displacement of the tensor starting from the target displacement. The control system can perform the extension test by automatically and progressively decreasing the displacement of the tensor and optionally according to displacements from the plurality of force-displacement data pairs. The tensor can comprise a user control input, such as a control button or slider. The control system can perform the extension test by progressively decreasing the displacement of the tensor in response to the user control input and optionally according to displacements from the plurality of force-displacement data pairs. During, or after completion of, the extension test, the control system can identify a first force-displacement data pair that enabled the knee joint to reach the acceptable full extension pose. After completion of the extension test, the control system can control the tensor to switch from the displacement control mode to the force control mode and optionally control the tensor in the force control mode to apply a second predetermined force to the knee joint when the knee joint is in a second acceptable flexion pose. The control system can control the tensor in the force control mode for applying a second predetermined force to the knee joint when the knee joint is in a second acceptable flexion pose. The control system can control the display device to provide visual guidance to aid in placing a current pose of the knee joint at the second acceptable flexion pose, and/or capture the current pose of the knee joint relative to the second acceptable flexion pose and/or control the display device to provide a visual confirmation in response to the current pose of the knee joint being at the second acceptable flexion pose. The second acceptable flexion pose can be a value from 80-105 degrees of knee joint flexion, such as 90 degrees. The control system can obtain the second predetermined force from a force from the first force-displacement data pair that enabled the knee joint to reach the acceptable full extension pose. The control system can obtain the second predetermined force from one of: a predetermined joint balancing force, a force based on a surgeon preference, a force obtained from statistical data, or a force from any of the force-displacement data pairs. While the knee joint is at the second acceptable flexion pose and during, or after, application of the second predetermined force to the knee joint, the control system can capture a second force-displacement data pair from the tensor. The control system can determine parameters of the knee joint based on the first force-displacement data pair that enabled the knee joint to reach the acceptable full extension pose and based on the second force-displacement data pair identified while the knee joint was at the second acceptable flexion pose. The parameters can be laxity parameters, such as laxity of medial and lateral compartments of the knee joint. The knee joint can include a femur with medial and lateral condyles and a tibia, and wherein the tensor further comprises a medial upper paddle and a lateral upper paddle that are each separately movable and can respectively engage the medial and lateral condyles of the femur, and at least one lower paddle can engage the tibia. In one example, first and second lower paddles of the first body and the second body collectively engage the tibia. The tensor can comprise a drive assembly comprising a first electric motor, and a first displacement mechanism coupled between the first electric motor and the medial upper paddle. The tensor can comprise a second electric motor, and a second displacement mechanism coupled between the second electric motor and the lateral upper paddle. The tensor can include a first sensor to sense force applied to the medial upper paddle. The tensor can include a second sensor to sense force applied to the lateral upper paddle. The control system can control the tensor in the force control mode by commanding the medial upper paddle and the lateral upper paddle to respectively apply forces to the medial and lateral condyles of the femur until the predetermined force is reached for one or both the medial upper paddle and the lateral upper paddle. The control system can capture the plurality of force-displacement data pairs further based on measurements from the first and second sensors and displacements of the medial upper paddle and the lateral upper paddle. The control system can control the tensor in the displacement control mode to perform the extension test by progressively decreasing the displacement of the medial upper paddle and the lateral upper paddle according to displacements from the plurality of force-displacement data pairs.
The sensor can include one or more of a load cell, strain gauge, pressure sensor, a displacement sensor, hall effect sensor, encoder, or the like. The sensor can move in accordance with movement of the displacement mechanism. The displacement mechanism can comprise a ball screw coupled to the electric motor and that can be rotated by the electric motor. The displacement mechanism can comprise a ball screw nut that can engage the ball screw. The ball screw nut can linearly displace along the ball screw pursuant to rotation of the ball screw by the electric motor. The displacement mechanism can comprise a ball spline shaft fixed to the ball screw nut and fixed to the upper paddle. The ball spline shaft can be linearly displaced in accordance with movement of the ball screw nut. The ball spline shaft can comprise a threaded interface that can receive a fastener. A variety of different sized upper paddles can attach to the tensor, such as by attaching to the ball spline shaft with the fastener. The tensor can receive a plurality of different sized lower paddles. The sensor can be located between the ball screw nut and the ball spline shaft, or between any other components of the displacement mechanism, such as any component within the load path of force applied to the upper paddle. The displacement mechanism can comprise an adapter disposed between the ball screw nut and the ball spline shaft. The adapter can be threaded to the ball screw nut. The adapter can be fixed to the ball spline shaft. The sensor can be located between the adapter and the ball screw nut. The sensor can be ring-shaped or disc shaped. The sensor can be disposed around the ball screw. The body of the tensor can be hermetically sealed. The body can be a first body and the tensor can include a second body that can be coupled relative to the first body. An upper paddle can be movable relative to the second body and can engage the first bone of the anatomical joint. A lower paddle can be coupled to the second body and can engage the second bone of the anatomical joint. A drive assembly can be disposed within the second body and can include an electric motor, and a displacement mechanism coupled between the electric motor and the upper paddle, and wherein the electric motor can move the displacement mechanism to linearly displace the upper paddle relative to the lower paddle. A sensor can sense force applied to the upper paddle, wherein the sensor is located in the displacement mechanism of the second body. The first body can be hermetically sealed. The second body can be hermetically sealed independent of the first body. The first and second bodies can be completely separated from one other.
A retainer can couple the first body and the second body relative to one another. The retainer can release the first body and the second body from the retainer such that the first body and the second body can be separated from one another. The retainer can define a first sleeve can receive the first body. The retainer can define a second sleeve can receive the second body. The first sleeve and second sleeve each can have a cylindrical configuration to hold a cylindrical portion of the first body and cylindrical portion of the second body, respectively. The sleeves can have any other shape (such as oval, rectangular, triangular, polygonal, etc.) to conform to the correspondingly shaped outer surface of the first and second bodies. Each of the first body and the second body can have a circumferential, annular, or perimeter-based feature that can respectively engage the first sleeve and the second sleeve to axially lock the first body and second body relative to the retainer. The locking mechanism can comprise a first locking mechanism coupled to the first sleeve and that can be actuated to rotationally lock the first body to the first sleeve. The locking mechanism can include a second locking mechanism coupled to the second sleeve and that can be actuated to rotationally lock the second body to the second sleeve. Each of the first sleeve and the second sleeve can include a size, opening, width, length, or a diameter that is adjustable. The locking mechanism can be actuated to simultaneously decrease the size, opening, width, length, or a diameter of each of the first and second sleeves to rotationally lock the first body and the second body relative to the retainer. The retainer can be split into a first portion and a second portion. Each of the first and second portions can partially define the first and second sleeves. The locking mechanism can be actuated to bring the first portion and the second portion of the retainer closer together to simultaneously and rotationally lock the first body and the second body relative to the retainer. Each of the first portion and the second portions can define inner teeth. Each of the first body and the second body can define outer teeth. The locking mechanism can be actuated to bring the first portion and the second portion closer together such that the inner teeth collectively engage to the outer teeth to simultaneously and rotationally lock the first body and the second body relative to the retainer. The retainer can comprise the first sleeve and the second sleeve being spaced apart from each other and a link portion connected between the first sleeve and the second sleeve. The link portion can be rigidly fixed between the first sleeve and the second sleeve. The first and second sleeves can be fixed relative to one another. The link portion can be adjustable. The link portion can include a rotational joint that can enable rotational movement between the first sleeve and the second sleeve and/or a prismatic joint that can enable translational movement between the first sleeve and the second sleeve. The locking mechanism or a separate locking mechanism can be actuated to lock the link portion. The locking mechanism or a separate locking mechanism can be couple to the one or more joints. When the link portion comprises one or more rotational joints, the rotational joints can enable rotational adjustment of the first body and the second body so as to enable rotational adjustment of the first set of paddles and the second set of paddles and the locking mechanism can to be actuated to lock the one or more rotational joints so as to rotationally lock the first body and the second body relative to one another. When the link portion comprises one or more translational joints, the translational joints can enable translational adjustment of the first body and the second body so as to enable translational adjustment of the first set of paddles and the second set of paddles and the locking mechanism can to be actuated to lock the one or more translational joints so as to translationally lock the first body and the second body relative to one another. The one or more joints can be spherical joints or gimbal joints. The locking mechanism can be at least one knob disposed external to the retainer and can be rotated in a first direction to rotationally lock the first body and the second body relative to the retainer and rotated in a second direction to rotationally unlock one, or both, of the first body and the second body relative to the retainer. The locking mechanism can be at least one lever disposed external to the retainer and moved in a first direction to rotationally lock one, or both, of the first body and the second body relative to the retainer moved in a second direction to rotationally unlock one, or both, of the first body and the second body relative to the retainer. The locking mechanism can be at least one button disposed external to the retainer and pushed to rotationally lock one, or both, of the first body and the second body relative to the retainer and/or pushed to rotationally unlock one, or both, of the first body and the second body relative to the retainer. The first electric motor can move the first displacement mechanism to linearly displace the first upper paddle along a first axis relative to the first lower paddle and the first body can rotate about the first axis within the retainer. The second electric motor can move the second displacement mechanism to linearly displace the second upper paddle along a second axis relative to the second lower paddle and the second body can rotate about the second axis within the retainer.
The orthopedic tensor can include the auxiliary paddle, as part of a kit or assembly. The orthopedic tensor can command movement of the upper paddle and/or the lower paddle relative to one another to capture the auxiliary paddle therebetween. The auxiliary paddle can be secured to the orthopedic tensor solely by being captured between the upper paddle and the lower paddle. The orthopedic tensor can operate in a force control mode to capture the auxiliary paddle. The orthopedic tensor can include a force sensor to sense force applied to the upper paddle. In the force control mode, the orthopedic tensor can command movement of the upper paddle towards the lower paddle until a predetermined force is detected by the force sensor. The predetermined force can be indicative of the auxiliary paddle being appropriately captured between the upper paddle and the lower paddle. In response to the distal portion contacting the first and second bones, the auxiliary paddle can apply force to the upper paddle. The force sensor can sense force applied to the upper paddle by the auxiliary paddle. The orthopedic tensor can operate in a displacement control mode to capture the auxiliary paddle. The orthopedic tensor can include a displacement sensor to sense displacement between the upper paddle and the lower paddle. In the displacement control mode, the orthopedic tensor can command movement of the upper paddle towards the lower paddle until a predetermined displacement between the upper paddle and lower paddle is detected by the displacement sensor. The predetermined displacement can be indicative of the auxiliary paddle being appropriately captured between the upper paddle and the lower paddle. In response to the distal portion contacting the first and second bones, the auxiliary paddle can apply force to the upper paddle and the displacement sensor can measure displacement between the upper paddle and the lower paddle in response to force applied to the upper paddle by the auxiliary paddle. The auxiliary paddle can pivot to apply force to the upper paddle in response to the distal portion contacting the first and second bones. The auxiliary paddle can include a rocker surface. The rocker surface can be contoured or curved and can engage the lower paddle. The rocker surface can enable the auxiliary paddle to pivot in response to the distal portion contacting the first and second bones. The auxiliary paddle can comprise a top surface opposite the rocker surface. The top surface can be planar and is configured to engage the upper paddle. The distal portion, the rocker surface, and the top surface of the auxiliary paddle can be part of a single, unitary, or monolithic body. The distal portion of the auxiliary paddle can include an auxiliary distal upper paddle that is configured to contact the upper paddle and contact the first bone and can include an auxiliary distal lower paddle that is configured to contact the lower paddle and contact the second bone. The auxiliary distal upper paddle can be pivotable relative to the auxiliary distal lower paddle to apply force to the upper paddle in response to the distal portion contacting the first and second bones. The upper paddle of the tensor is designed to contact the first bone and the lower paddle of the tensor is designed to contact the second bone. When the auxiliary paddle is captured, the distal portion of the auxiliary paddle provides a substitute for the upper paddle and the lower paddle for contacting the first and second bones. The first and second bones of the anatomical joint can be non-resected bones and the lower paddle is designed to engage a resected surface of the second bone. The auxiliary paddle can provide a substitute for the lower paddle to engage non-resected surface of the second bone. The upper paddle of the tensor has a bottom surface configured to engage the auxiliary paddle. The lower paddle has a top surface configured to engage the auxiliary paddle. The bottom surface of the upper paddle and the top surface of the lower paddle can cooperate to capture the auxiliary paddle. The upper paddle and lower paddle of the tensor each a length defined between a proximal end and a distal end. The auxiliary paddle has a length defined between a proximal end and a distal end of the distal portion, wherein the length of the auxiliary paddle can be greater than the length of the upper paddle and greater than the length of the lower paddle. The auxiliary paddle can include a body portion that can rest on the lower paddle. The body portion can have a shape that substantially conforms to a shape of the lower paddle. The tensor body can be used in an inverted or upside-down orientation. The tensor body can have an inverted or upside-down configuration whereby the upper paddle pulls up instead of pushing up on the femur. Spacers can be selectively coupled to any paddle of any tensor configuration.
The inventors have contemplated that any of the implementations above can be combined in part, or in whole with any aspects described herein.
Advantages of the present disclosure will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.
Referring to
The system 10 can include a manipulator 14. The manipulator 14 has a base 16 and plurality of links 18. A manipulator cart 17 supports the manipulator 14 such that the manipulator 14 is fixed to the manipulator cart 17. The links 18 collectively form one or more arms of the manipulator 14. The manipulator 14 may have a serial arm configuration (as shown in
In the example shown in
The manipulator 14 need not require joint encoders 19 but may alternatively, or additionally, utilize motor encoders present on motors at each joint J. Also, the manipulator 14 need not require rotary joints, but may alternatively, or additionally, utilize one or more prismatic joints. Any suitable combination of joint types is contemplated.
The base 16 of the manipulator 14 is a portion of the manipulator 14 that provides a fixed reference coordinate system for other components of the manipulator 14 or the system 10 in general. The origin of a manipulator coordinate system MNPL is defined at the fixed reference of the base 16. The base 16 may be defined with respect to any suitable portion of the manipulator 14, such as one or more of the links 18. Alternatively, or additionally, the base 16 may be defined with respect to the manipulator cart 17, such as where the manipulator 14 is physically attached to the manipulator cart 17. In one example, the base 16 is defined at an intersection of the axes of joints J1 and J2. Thus, although joints J1 and J2 are moving components in reality, the intersection of the axes of joints J1 and J2 is nevertheless a virtual fixed reference pose, which provides both a fixed position and orientation reference and which does not move relative to the manipulator 14 and/or manipulator cart 17. In other examples, the manipulator 14 can be a hand-held manipulator where the base 16 is a base portion of a tool (e.g., a portion held free hand by the user) and the tool tip is movable relative to the base portion. The base portion has a reference coordinate system that is tracked and the tool tip has a tool tip coordinate system that is computed relative to the reference coordinate system (e.g., via motor and/or joint encoders and forward kinematic calculations). Movement of the tool tip can be controlled to follow the path since its pose relative to the path can be determined.
The manipulator 14 and/or manipulator cart 17 house a manipulator controller 26, or other type of control unit. The manipulator controller 26 may comprise one or more computers, or any other suitable form of controller that directs the motion of the manipulator 14. The manipulator controller 26 may have a central processing unit (CPU) and/or other processors, memory (not shown), and storage (not shown). The manipulator controller 26 is loaded with software as described below. The processors could include one or more processors to control operation of the manipulator 14. The processors can be any type of microprocessor, multi-processor, and/or multi-core processing system. The manipulator controller 26 may additionally, or alternatively, comprise one or more microcontrollers, field programmable gate arrays, systems on a chip, discrete circuitry, and/or other suitable hardware, software, or firmware that is capable of conducting the functions described herein. The term processor is not intended to limit any embodiment to a single processor. The manipulator 14 may also comprise a user interface UI with one or more displays and/or input devices (e.g., push buttons, keyboard, mouse, microphone (voice-activation), gesture control devices, touchscreens, etc.).
A tool 20 couples to the manipulator 14 and is movable relative to the base 16 to interact with the anatomy in certain modes. The tool 20 is a physical and surgical tool and is, or forms part of, an end effector 22 supported by the manipulator 14 in certain implementations. The tool 20 may be grasped by the user. One possible arrangement of the manipulator 14 and the tool 20 is described in U.S. Pat. No. 9,119,655, entitled, “Surgical Manipulator Capable of Controlling a Surgical Instrument in Multiple Modes,” the disclosure of which is hereby incorporated by reference. The manipulator 14 and the tool 20 may be arranged in alternative configurations. The tool 20 can be like that shown in U.S. Patent Application Publication No. 2014/0276949, filed on Mar. 15, 2014, entitled, “End Effector of a Surgical Robotic Manipulator,” hereby incorporated by reference.
The tool 20 can include an energy applicator 24 designed to contact, evaluate, or remove the tissue of the patient 12 at the surgical site. In one example, the energy applicator 24 is a bur 25. The bur 25 may be substantially spherical and comprise a spherical center, radius (r) and diameter. Alternatively, the energy applicator 24 may be a drill bit, a saw blade, an ultrasonic vibrating tip, or the like. In other examples, the tool 20 does not include an energy applicator 24. For example, the tool 20 can be a slotted cut guide for a saw, a guide tube for receiving another tool, or the like.
The tool 20 may comprise a tool controller to control operation of the tool 20, such as to control power to the tool (e.g., to a rotary motor of the tool 20), control movement of the tool 20, control irrigation/aspiration of the tool 20, and/or the like. The tool controller may be in communication with the manipulator controller 26 or other components. The tool 20 may also comprise a user interface UI with one or more displays and/or input devices (e.g., push buttons, keyboard, mouse, microphone (voice-activation), gesture control devices, touchscreens, etc.). For example, one of the user input devices on the user interface UI of the tool 20 may be a tool input (e.g., switch or other form of user input device) that has first and second input states (see
The system 10 further includes a navigation system 32. One example of the navigation system 32 is described in U.S. Pat. No. 9,008,757, filed on Sep. 24, 2013, entitled, “Navigation System Including Optical and Non-Optical Sensors,” hereby incorporated by reference. The navigation system 32 tracks movement of various objects. Such objects include, for example, the manipulator 14, the tool 20 and the anatomy, e.g., femur F and tibia TIB. The navigation system 32 tracks these objects to gather state information of each object with respect to a (navigation) localizer coordinate system LCLZ. Coordinates in the localizer coordinate system LCLZ may be transformed to the manipulator coordinate system MNPL, and/or vice-versa, using transformations.
The navigation system 32 can include a cart assembly 34 that houses a navigation controller 36, and/or other types of control units. A navigation user interface UI is in operative communication with the navigation controller 36. The navigation user interface includes one or more displays 38. The navigation system 32 is capable of displaying a graphical representation of the relative states of the tracked objects to the user using the one or more displays 38. The navigation user interface UI further comprises one or more input devices to input information into the navigation controller 36 or otherwise to select/control certain aspects of the navigation controller 36. Such input devices include interactive touchscreen displays. However, the input devices may include any one or more of push buttons, a keyboard, a mouse, a microphone (voice-activation), gesture control devices, and the like. In some instances, the display 38 can be a head-mounted device that includes a display positioned in front of the eyes of the user. The head-mounted device can be configured to present mixed reality or augmented reality computer images over real-world images of objects or the surgical site. The head-mounted device can display any of the media described herein and can be like that described in U.S. Pat. No. 10,499,997, entitled “Systems and Methods for Surgical Navigation” the entire contents of which are hereby incorporated by reference.
The navigation system 32 also includes a navigation localizer 44 coupled to the navigation controller 36. In one example, the localizer 44 is an optical localizer and includes a camera unit 46. The camera unit 46 has an outer casing 48 that houses one or more optical sensors 50. The localizer 44 may comprise its own localizer controller 49 and may further comprise a video camera VC.
The navigation system 32 can include one or more trackers. In one example, the trackers include a pointer tracker PT, one or more manipulator trackers 52A, 52B, 52C a first patient tracker 54, and a second patient tracker 56. In the illustrated example of
Any one or more of the trackers may include active markers 58. The active markers 58 may include light emitting diodes (LEDs). Alternatively, the trackers 52, 54, 56, PT may have passive markers, such as reflectors, which reflect light emitted from the camera unit 46. Other suitable markers not specifically described herein may be utilized.
The localizer 44 can track the trackers 52, 54, 56, PT to determine a state of each of the trackers 52, 54, 56, PT, which correspond respectively to the state of the object respectively attached thereto. The localizer 44 may perform known triangulation techniques to determine the states of the trackers 52, 54, 56, PT, and associated objects. The localizer 44 provides the state of the trackers 52, 54, 56, PT to the navigation controller 36. In one example, the navigation controller 36 determines and communicates the state the trackers 52, 54, 56, PT to the manipulator controller 26. As used herein, the state of an object includes, but is not limited to, data that defines the position and/or orientation of the tracked object or equivalents/derivatives of the position and/or orientation. For example, the state may be a pose of the object, and may include linear velocity data, and/or angular velocity data, and the like.
The navigation controller 36 may comprise one or more computers, or any other suitable form of controller. Navigation controller 36 has a central processing unit (CPU) and/or other processors, non-transitory memory (not shown), and storage (not shown). The processors can be any type of processor, microprocessor, or multi-processor system. The navigation controller 36 is loaded with software. The software, for example, converts the signals received from the localizer 44 into data representative of the position and orientation of the objects being tracked. The navigation controller 36 may additionally, or alternatively, comprise one or more microcontrollers, field programmable gate arrays, systems on a chip, discrete circuitry, and/or other suitable hardware, software, or firmware that is capable of conducting the functions described herein. The term processor is not intended to limit any embodiment to a single processor.
Although one example of the navigation system 32 is shown that employs triangulation techniques to determine object states, the navigation system 32 may have any other suitable configuration for tracking the manipulator 14, tool 20, and/or the patient 12.
In another example, the navigation system 32 and/or localizer 44 are ultrasound-based. For example, the navigation system 32 may comprise an ultrasound imaging device coupled to the navigation controller 36. The ultrasound imaging device images any of the aforementioned objects, e.g., the manipulator 14, the tool 20, and/or the patient 12, and generates state signals to the navigation controller 36 based on the ultrasound images. The ultrasound images may be 2-D, 3-D, or a combination of both. The navigation controller 36 may process the images in near real-time to determine states of the objects. The ultrasound imaging device may have any suitable configuration and may be different than the camera unit 46 as shown in
In another example, the navigation system 32 and/or localizer 44 are radio frequency (RF)-based. For example, the navigation system 32 may comprise an RF transceiver coupled to the navigation controller 36. The manipulator 14, the tool 20, and/or the patient 12 may comprise RF emitters or transponders attached thereto. The RF emitters or transponders may be passive or actively energized. The RF transceiver transmits an RF tracking signal and generates state signals to the navigation controller 36 based on RF signals received from the RF emitters. The navigation controller 36 may analyze the received RF signals to associate relative states thereto. The RF signals may be of any suitable frequency. The RF transceiver may be positioned at any suitable location to track the objects using RF signals effectively. Furthermore, the RF emitters or transponders may have any suitable structural configuration that may be much different than the trackers 52, 54, 56, PT shown in
In yet another example, the navigation system 32 and/or localizer 44 are electromagnetically based. For example, the navigation system 32 may comprise an EM transceiver coupled to the navigation controller 36. The manipulator 14, the tool 20, and/or the patient 12 may comprise EM components attached thereto, such as any suitable magnetic tracker, electro-magnetic tracker, inductive tracker, or the like. The trackers may be passive or actively energized. The EM transceiver generates an EM field and generates state signals to the navigation controller 36 based upon EM signals received from the trackers. The navigation controller 36 may analyze the received EM signals to associate relative states thereto. Again, such navigation system 32 examples may have structural configurations that are different than the navigation system 32 configuration shown in
In yet another example, the navigation system 32 and/or localizer 44 utilize a machine vision system which includes a video camera coupled to the navigation computer 36. The video camera is configured to locate a physical object in a target space. The physical object has a geometry represented by virtual object data stored by the navigation computer 36. The detected objects may be tools, obstacles, anatomical features, trackers, or the like. The video camera and navigation computer 36 are configured to detect the physical objects using image processing techniques such as pattern, color, or shape recognition, edge detection, pixel analysis, neutral net or deep learning processing, optical character recognition, barcode detection, or the like. The navigation computer 36 can compare the captured images to the virtual object data to identify and track the objects. A tracker may or may not be coupled to the physical object. If trackers are utilized, the machine vision system may also include infrared detectors for tracking the trackers and comparing tracking data to machine vision data. Again, such navigation system 32 examples may have structural configurations that are different than the navigation system 32 configuration as shown throughout the Figures. Examples of machine vision tracking systems can be like that described in U.S. Pat. No. 9,603,665, entitled “Systems and Methods for Establishing Virtual Constraint Boundaries” and/or like that described in U.S. Pat. No. 11,291,507, entitled “Systems and Method for Image Based Registration and Calibration,” the entire contents of which are incorporated by reference herein.
The navigation system 32 may have any other suitable components or structure not specifically recited herein. Furthermore, any of the techniques, methods, and/or components described above with respect to the navigation system 32 shown may be implemented or provided for any of the other examples of the navigation system 32 described herein. For example, the navigation system 32 may utilize solely inertial tracking or any combination of tracking techniques, and may additionally or alternatively comprise, fiber optic-based tracking, machine-vision tracking, and the like.
Referring to
The control system 60 may comprise any suitable configuration of input, output, and processing devices suitable for conducting the functions and methods described herein. The control system 60 may comprise the manipulator controller 26, the navigation controller 36, or the tool controller 21, or any combination thereof, or may comprise only one of these controllers. These controllers may communicate via a wired bus or communication network as shown in
A clinical application CA may be provided to manage user interaction. The clinical application CA manages many aspects of user interaction and coordinates the surgical workflow, including pre-operative planning, joint assessment, implant placement, registration, bone preparation visualization, and post-operative evaluation of implant fit, etc. The clinical application CA is configured to output to any of the displays 38.
Described in this section are configurations and methods of using an orthopedic tensor T (hereinafter “tensor”) for evaluating an anatomical joint AJ. The anatomical joint AJ chiefly described herein is a knee joint including a femur F and tibia TIB. However, the anatomical joint AJ can be any other joint, such as a hip joint, shoulder joint, elbow joint, ankle joint, etc. The tensor T is inserted into the anatomical joint AJ to evaluate soft tissue and ligaments of the anatomical joint AJ. The tensor T can be used to evaluate laxity, stiffness, ligament balance, kinematics, flexion, extension and/or range of motion of the anatomical joint AJ. Configurations and uses of the orthopedic tensor T will be described in detail below. The tensor T can be used for total knee arthroplasty procedures, partial knee arthroplasty procedures, anatomical shoulder arthroplasty procedures, reverse shoulder arthroplasty procedures, or any other procedure requiring evaluation of adjacent bones. The tensor T can be used to evaluate bones that are pre-resected, mid-resected, post-resected, or one or more bones that include a prosthetic implant coupled to the bone.
In most cases, the tensor T is intended to be held and support by the hand(s) of the user. However, in some examples, the tensor T can be the tool 20 coupled to the manipulator 14. The tensor T can be actively or passively coupled to the manipulator 14. When passively coupled, the tensor T can be held in certain positions by the manipulator 14 to facilitate any of the methods described herein for evaluating the anatomical joint AJ and the user controls the tensor T independent of the robot control. When actively coupled, the manipulator 14 control system can be coupled to control system of the tensor T to coordinate these two systems. The tensor T can be selectively attached to and removed from the manipulator 14 at the desire of the user. The tensor T can be utilized with or without the system 10 described above and can be utilized with any type of surgical system besides the system 10 specifically shown.
Referring to
The first body TB1 and the second body TB2 each include an upper paddle UP and a lower paddle LP. To separate the bones B1, B2, the upper paddle UP of each body TB1, TB2 is configured to move relative to the lower paddle LP of each body TB1, TB2. Each lower paddle LP is fixed relative to the respective body TB1, TB2. In other configurations, both the upper paddle UP and lower paddle LP can move or the lower paddle LP can move relative to a fixed upper paddle UP. In some configurations, the first and second bodies TB1, TB2 can share a common lower paddle LP.
The upper paddle UP of each body TB1, TB2 is configured to engage a first bone B1 of the anatomical joint AJ and the lower paddle LP of each body TB1, TB2 is configured to engage a second bone B2 of the anatomical joint AJ. In
With reference to
The first body TB1 includes a drive assembly DA coupled to or disposed within the body TB1. The drive assembly DA includes an electric motor M, such as a brushless DC motor. The motor M is in a fixed position relative to the body TB1. A displacement mechanism DM is coupled between the electric motor M and the upper paddle UP. The electric motor M is configured to move the displacement mechanism DM to linearly displace the upper paddle UP relative to the lower paddle LP.
In one implementation, the displacement mechanism DM can comprise a ball screw BS coupled to the electric motor M and that can be rotated by the electric motor M. A ball screw nut BN can engage the ball screw BS. The ball screw nut BN can linearly move up or down along the ball screw BS pursuant to a direction of rotation of the ball screw BS by the electric motor M. The displacement mechanism DM can comprise a ball spline shaft BSS fixed to the ball screw nut BN and fixed to the upper paddle. The ball spline shaft BSS and ball screw nut BN can be a single unit or separately coupled components. The ball spline shaft BSS can be linearly displaced in accordance with movement of the ball screw nut BN. The upper paddle UP will move in correspondence with the ball spline shaft BSS. The ball spline shaft BSS can include an internal bore to receive and provide clearance for the ball screw BS as the ball spline shaft BSS is axially moved. A ball spline nut BSN can be fixed relative to the body TB1 and can surround the ball spline shaft BSS. The ball spline nut BSN can provide an internal guiding channel and linear bearing surface to facilitate movement of the ball spline shaft BSS. The tight fitting of the ball spline nut BSN also maintains sealing of the internal components of the body TB1 and eliminates the need for a bellows for scaling between the body TB1 and the upper paddle UP. The displacement mechanism DM can also include a jam nut JN disposed between the ball screw nut BN and the ball spline shaft BSS. The jam nut JN moves with the ball screw nut BN and can be provided to stop upward movement of the ball screw nut BN by abutting an internal flange within the body TB1. The ball spline shaft BSS can comprise a threaded interface that can receive a fastener FN. A variety of different sized upper paddles UP can attach to the body TB1, such as by attaching to upper paddle UP to the ball spline shaft BSS with the fastener FN. The upper paddle UP can be removed from the body TB1 by removing the fastener FN. The lower paddle LP is fixed to the body TB1. However, in other configurations, when the upper paddle UP is removed, any one of a variety types of lower paddles LP can be installed to the body TB1 by sliding the lower paddle LP over the ball spline shaft BSS and securing the lower paddle LP to the body TB1.
Above the motor M, a hard stop HS can be provided to stop downward movement of the ball screw nut BN. The hard stop HS can be spaced specifically so that once the ball screw nut BN reaches the hard stop HS, the upper paddle UP will be in a closed position relative to the lower paddle LP, i.e., touching the lower paddle LP, without overdriving the upper paddle UP. The hard stop HS can also protect the motor M from contact by the ball screw nut BN.
Below the motor M, axially, is a printed circuit board PCB supporting operation of the motor and a tensor encoder EN for sensing the rotational position of the motor M. The encoder EN may comprise a magnetic based sensor, such as a Hall effect sensor. The encoder EN can function as a displacement sensor for sensing the displacement of the upper paddle UP relative to the lower paddle LP.
A cable C can be coupled to the tensor T. The cable C is connectable to a power source and/or control system TCS for the tensor T. The cable C can exit to the body TB1 through a cable seal. Control signals for the tensor T can be provided through the cable C. Power to the tensor T components, such as the motor M, PCB, and sensor S can also be provided through the cable C. Alternatively, the body TB1 may be battery (self) powered. A replaceable or rechargeable battery unit can be coupled to the body TB1, such as by attaching to a lower end of the body TB1, e.g., beneath the motor M and PCB. The body TB1 can include battery terminals that interface to corresponding terminals of the battery unit. The battery unit and/or the body TB1 can provide a seal to prevent fluid from reaching the battery terminals. The body TB1 can also include one or more user input devices TID for providing control signals through to the tensor T. The user input devices TID can be coupled to the PCB and can take any form, such as buttons, sliders, knobs, switches, triggers, which are accessible from the external surface of the body and actuated by the user.
The body TB1 can be disassembled. For example, with continued reference to
The configuration of the drive assembly DA and the displacement mechanism DM are not limited to the configuration shown and described above. For example, instead of a ball screw system, the displacement mechanism DM could include a lead screw with a carriage, a planetary roller actuator system, a worm gear system, or the like. Any of the features described above, or their equivalents, can be utilized with the second body TB2 of the tensor T.
2a. Sensor Included with Displacement Mechanism
With continued reference to
In the example shown, the sensor S is located in the displacement mechanism DM and/or configured to move in accordance with movement of the displacement mechanism DM. In one implementation, the sensor S can be located between the ball screw nut BN and the ball spline shaft BSS. The displacement mechanism DM can comprise a sensor adapter SA disposed between the ball screw nut BN and the ball spline shaft BSS. The sensor adapter SA can be fixed to the ball spline shaft BSS and engaged to the ball screw nut BN with threads. The sensor S can be located between the sensor adapter SA and the ball screw nut BN. The sensor S can be attached directly to the sensor adapter SA or simply captured between the components. The sensor S will move in correspondence with the ball screw nut BN. Alternatively, the sensor S can be located between any other components of the displacement mechanism DM, such as any component in the load path of force applied to the upper paddle UP.
The sensor S can be ring-shaped or disc shaped such that the sensor S can be disposed around the ball screw BS. This annular configuration of the sensor S provides reliable and accurate load measurements for any directional force applied to the upper paddle UP. The sensor S can be wired along the inner surface of the body TB1 to circumvent the path of the ball screw nut BN and avoid pinching of the cable. The sensor S can be connected to the PCB. Again, any reference throughout to what the first body TB1 may include is fully applicable to what the second body TB1 may include and is not repeated for simplicity.
By having the sensor S located in, or moving with, the displacement mechanism DM, the tensor T provides several improvements. The load path between the upper paddle the sensor S is minimized in length because the sensor S is positioned closer to the applied force, thereby improving accuracy in measurement. The motor M can remain in an axially fixed position without being subjected to load from the upper paddle. In other words, the motor M is not required to axially move to enable the sensor S to sense the force because the sensor S is located above the motor M. Having the sensor S below the motor M will require the motor M to experience some axial force and will require additional flexure components to enable movement of the motor M. By having the sensor S in the displacement mechanism, the tensor T eliminates the need for adding complaint, flexure components and increases robustness of the drive assembly DA by maintaining the axial position of the motor M.
2b. Sensor Included with Paddle
In addition to, or instead of, having the sensor S in the displacement mechanism, the sensor S can be included directly with the paddle, as shown in
The paddle UP, LP can be configured with one or more openings or slots SL formed into the body of the paddle UP, LP. The slot SL can have any suitable shape, such as a circle, oval, pill, discorectangle, obround, stadium, rectangle, or any other complex shape. For example, as shown in
The one or more slots SL are configured to deform in response to a load or force (shown as F) applied to the respective paddle UP, LP. The one or more slots SL are configured to provide a pivot point for the respective paddle UP, LP in response to the force applied to the respective paddle UP, LP. By deforming and providing a pivot point, the one or more slots SL enable the respective paddle UP, LP to experience a displacement (D) relative to the at-rest position of the paddle. For example, in response to an applied load to the paddle UP, LP, the one or more slots SL can create a four-bar type mechanism to enable the displacement D of the paddle. The flexion and corresponding displacement D of the paddle UP, LP depends on the magnitude of the applied force and the location and direction of the force relative to the length of the paddle. The respective paddle UP, LP can be formed of any suitable material to enable its deformation, including but not limited to stainless steel, such as 17-4, 440C, or 900 grade stainless steel.
The deformation of the one or more slots SL is proportional to, or correlated to, the applied force. Hence, the deformation of the one or more slots SL can be measured to deduce the respective force F applied to the paddle. The sensor S can be implemented by providing one or more strain gauges SG on the paddle. The strain gauge has wires (not shown) of a resistive element that attach to a surface adjacent to the slot SL. A length of the surface of the slot SL expands or contracts in response to the load. The strain gauge is a passive device that changes resistance in response to changes in strain on the surface adjacent to the slot SL. That is, a length of the wires changes in response to changes in the length of the surface. The resistance of the wires changes in response to changes to the length of the electrical wires. Resistance in the strain gauge increases when the surface goes into tension and the resistance in the strain gauge decreases when the surface goes into compression. Strain is proportional to the change in resistance of the strain gauge. The change in resistance is deduced by measuring the voltage across the strain gauge. Any suitable resistance measuring means may measure the change in electrical resistance. The one or more strain gauges can be located relative to the one or more slots SL. In these configurations, the sensor S can utilize the one or more slots SL and strain gauges SG to implement as a load cell.
In the example of
The strain gauge(s) SG can be coupled to any of the described controller(s), such as the motor controller MC and behavior controller BC, which can be located in the tensor body TB. In one example, this coupling is made through electrical wires. To enable the wires to adapt to movement of the respective paddle UP, LP, the tensor body TB can include a channel for the wire and the wire may include a service loop to provide slack. Alternatively, the strain gauge(s) SG can communicate signals via wireless communication (e.g., radio frequency, or otherwise). A compact wireless communicate device can be embedded within the paddle, for instance.
By incorporating the slot SL and strain gauge SG configuration (e.g., load cell) directly on/into the body of the paddle, the described configurations provide a more compact sensor S design. Moreover, a more accurate force measurement is provided by having the load cell be located directly next to the source of the force on the paddle (e.g., as compared with further away from the force).
As shown in at least
As shown in
Additionally, by each body TB1, TB2 including a separate set of upper and lower paddles UP, LP, the footprint of the paddles can be reduced in size. For example, by including two smaller lower paddles LP, the design can eliminate a single lower paddle that has large profile with non-useful surface area. The small footprint of the paddles UP, LP can facilitate easy insertion of the tensor T into the knee joint AJ.
Advantageously, as shown in
With reference to
The tensor T can utilize, or can be utilized with, localizer 44 information derived from the tracked poses of the anatomical joint AJ, such as the poses of the femur and tibia. Optionally, the tensor T can be tracked by the navigation system 32. A tracker can optionally be coupled to the tensor T, or any moveable or static components of the tensor T, such as the paddles. In other instances, the tensor T need not be tracked.
The tensor control system TCS includes one or more motor controllers MC coupled to the drive assembly DA for executing a commanded action (position or force) for the drive assembly DA, and ultimately the upper paddle UP. The motor controller MC can control power to the drive assembly DA and its respective components. For example, the motor controller MC can provide 3-phase motor power to the motor M. The motor controller MC can be implemented on the PCB of each body TB1, TB2, or implemented remote from each body TB1, TB2. When implemented in the tensor T, each body TB1, TB2 can include its own dedicated motor controller MC. When implemented remote from the tensor T, one motor controller MC can be utilized to control both drive assemblies DA. The motor controller MC can receive feedback from the drive assembly DA, including feedback from the encoder EN, sensor S, or motor M. The motor controller MC can control the motor M based on the feedback signals. The feedback signals can relate to position, velocity, acceleration, force, commutation, gain, or any other parameters experienced by, or exhibited by any component of the drive assembly DA. In one version, the motor controller MC regulates the motor M and continually adjusts the torque that motor M outputs to, as closely as possible, ensure that the motor M drives the displacement mechanism DM to the commanded position or force. In some examples, the motor controller MC is proportional integral derivative (PID) controllers. Other types of controllers are contemplated.
The tensor control system TCS includes one or more behavior controllers BC. The behavior controller BC is coupled to the motor controller MC and provides commands to the motor controller MC. For example, the behavior controller BC can command the motor controller MC to move the upper paddle UP to a commanded position or until a force applied to the upper paddle UP is reached. Output from the sensor S or encoder EN can be utilized by the behavior controller BC when commanding the motor controller MC. For example, as shown in
As shown in
As shown in
It is contemplated that aspects of the force control mode FCM and the displacement control mode DCM can be simultaneously implemented or combined in a single mode, i.e., a force-displacement control mode. In one implementation, in the force-displacement control mode, the drive assembly DA is commanded to move the upper paddle UP according to a predetermined position/displacement until a predetermined force sensed by the sensor S is reached. In another implementation, in the force/displacement control mode, the drive assembly DA is commanded to move the upper paddle UP to apply a predetermined force until to a predetermined position/displacement is reached. Hence, in the force-displacement control mode, force and displacement can be commanded until one, or both, of the commanded force or displacement is reached. Any of the above aspects and implementations of the force control mode FCM and the displacement control mode DCM can be equally applied to the force-displacement control mode.
The tensor T can comprise one of many configurations to facilitate unique adjustability of the first and second bodies TB1, TB2. As will be understood from the following description, the adjustability of the tensor T enables the tensor T to accommodate various sized bones of any knee joint. The first and second bodies TB1, TB2 can be uniquely adjusted to enable quick evaluation of both the left knee or the right knee without requiring replacement of paddles or reconfiguration. Adjustability of the bodies TB1, TB2 further reduces the likelihood of slippage of the tensor T from the joint AJ and reduces the likelihood of impingement with the patellar tendon PAT.
With reference to
The retainer R can facilitate quick release the bodies TB1, TB2 such that the bodies TB1, TB2 can be removed from the retainer R and separated from one another. This can be done by releasing the locking mechanism LM from a locked state into a released state. Advantageously, removing the bodies TB1, TB2 from the retainer R can facilitate case in cleaning or sterilization of the bodies TB1, TB2 and retainer R.
As shown throughout
As shown in
To facilitate ergonomic rotation within the retainer R, each body TB1, TB2 can have gripping features G located on a surface of the body. For example, as shown in
Referring to
With reference to
In the example of
In the example of
In another example, the locking mechanism LM can include a button that can be coupled to a mechanical or electromechanical system for facilitating locking of the retainer R. For example, the retainer R could comprise a motor that is coupled to a lead screw that is coupled between the portions RP1, RP2 (like that shown in
It is contemplated to have the sleeves SL2, SL2 of the retainer R be individually and/or separably actuated.
Several retainer R configurations described above include the link portion LKP rigidly coupled between the sleeves SL1, SL2 for fixing the lateral position of the sleeves SL1, SL2, or sleeve portions, relative to one another. In this section, and with reference to
In these examples, it is contemplated that the adjustable link portion ALKP may be utilized in addition to the retainer R or without the retainer R. For example, the sleeves SL1, SL2 could be non-adjustable such that the sleeves SL1, SL2 could be permanently or semi-permanently coupled to each respective body TB1, TB2. Hence, the locking mechanism LM may or may not be utilized for each sleeve SL1, SL2. Alternatively, the adjustable link portion ALKP may be directly coupled to each respective tensor body TB1, TB2 so that no sleeve is required. The degrees of freedom provided by the adjustable link portion ALKP may be sufficient to enable the rotational adjustment of each body TB1, TB2.
In the example of
Optionally, a link portion locking mechanism LPLM can be operatively coupled to the link portion joint LPJ to facilitate locking and unlocking of the link portion joint LPJ. In turn, the link portion locking mechanism LPLM can translationally lock/unlock the sleeves SL1, SL2, and the bodies TB1, TB2 relative to one another. For any of the example described herein, the link portion locking mechanism LPLM can include a configuration or user interface similar to the locking mechanism LM described in the examples of
In the example of
Additionally, the adjustable link portion ALKP may comprise more than one rotational link portion joint LPJ or the rotational link portion joint LPJ providing greater than one degree of freedom in rotation. For example, a second rotational link portion joint LPJ may be provided perpendicular to the rotational link portion joint LPJ shown in
The link portion locking mechanism LPLM can be operatively coupled to the link portion joint LPJ to facilitate locking and unlocking of the link portion joint LPJ. In turn, the link portion locking mechanism LPLM can rotationally lock/unlock the sleeves SL1, SL2, and the bodies TB1, TB2 relative to one another. For example, a knob can be used to lock/unlock a gimbal joint.
Additionally, the adjustable link portion ALKP may combine the above implementations in any manner to include one or more link portion joints LPJ that provide both translational and rotational degrees of freedom (up to six degrees of freedom).
Referring to
The auxiliary paddle AP is configured to be inserted between and captured by the upper paddle UP and the lower paddle LP of one body TB1. More specifically, the auxiliary paddle AP is configured to be captured between the bottom surface UBS of the upper paddle UP and the top surface LTS of the lower paddle LP (as can be seen in
The configurations and implementations of the auxiliary paddle AP will now be described. With reference to one example, as shown in
The distal portion ADP extends from the proximal portion APP. The distal portion ADP is the part of the auxiliary paddle AP that is configured to directly contact the first and second bones B1, B2 of the anatomical joint AJ. Once the auxiliary paddle AP is inserted into the tensor T, the distal portion ADP will extend beyond a distal end PDE of each of the paddles UP, LP. As will be described below, there are instances in which portions of the distal portion ADP may be captured between the upper and lower paddles UP, LP.
As shown in
The auxiliary paddle AP comprises a pivot APVT being provided on the body APB of the auxiliary paddle AP and/or coupled to the distal portion ADP of the auxiliary paddle AP. The pivot APVT is designed to enable the auxiliary paddle AP to apply force to the upper paddle UP in response to the distal portion ADP contacting the first and/or second bones B1, B2 of the anatomical joint AJ. The effort exerted by the bones on the distal portion ADP causes the auxiliary paddle AP to apply a load to the upper paddle UP. The auxiliary paddle AP is utilized in conjunction with the existing paddles UP, LP and the tensor control system TCS. When the auxiliary paddle AP is captured, the distal portion ADP of the auxiliary paddle AP can be understood as a substitute for the upper and lower paddles UP, LP with respect to contacting the bones.
In the example shown in
As shown in the example of
In some instances, same configuration of the auxiliary paddle AP (as shown in
The body APB of the auxiliary paddle AP, including the distal portion ADP, the rocker surface RS, and the top surface ATS can be part of a single, unitary, or monolithic body or integrally formed of a common material. The common material can be a metal, metal alloy, PTFE, or the like. Alternatively, any features of the body APB could be separate components that are assembled onto the body. For example, the rocker surface RS could include a separate component formed of different material than the body APB.
In another example shown in
As shown in
An open state of the auxiliary paddle AP is demonstrated in
Modifications are contemplated to the auxiliary paddle AP configuration of
6B. Tensor Control Schemes for Use with Auxiliary Paddle
Here, operation of tensor control system TCS will be described in conjunction with use of the auxiliary paddle AP. The tensor control system TCS can be utilized to facilitate capture the auxiliary paddle AP and to facilitate sensing of displacement or force caused by the auxiliary paddle AP interacting with the bones.
First, the auxiliary paddle AP is inserted into the tensor T or body TB1, e.g., between the paddles UP, LP (as shown in
As described in the preceding sections, the tensor T can operate in the displacement control mode DCM, force control mode FCM, or force-displacement control mode. Any of these modes can be utilized to capture the auxiliary paddle AP and to obtain measurements resulting from the auxiliary paddle AP contacting the bones. The tensor control system TCS can be controlled to trigger the capture of the auxiliary paddle AP through the clinical application CA and/or through user input TID devices on the tensor T itself.
To capture the auxiliary paddle AP in the displacement control mode DCM, the tensor control system TCS commands displacement of the upper paddle UP towards the lower paddle LP. This process can be manually guided or automatically implemented. In one example, the tensor control system TCS can automatically lower the upper paddle UP until a predetermined capture displacement between the upper paddle UP and lower paddle LP is detected or reached. The predetermined capture displacement can be utilized to prevent overdriving the upper paddle UP onto the auxiliary paddle AP and possibly damaging the system components. The predetermined capture displacement can be detected by a displacement or position sensor, such as the motor encoder M, or any other sensing system described herein. The predetermined capture displacement can be indicative of the auxiliary paddle AP being appropriately or sufficiently captured between the paddles UP, LP. For example, the tensor control system TCS can include predetermined data related to the geometry of the auxiliary paddle AP and derive the predetermined capture displacement from such data. In one example, the predetermined capture displacement can be defined by a difference between a current spacing between the paddles UP, LP and the thickness of the auxiliary paddle AP. In another example, the paddles UP, LP may be automatically placed in a maximum opened position and then the upper paddle UP can be automatically lowered by the predetermined capture displacement. The maximum opened position can provide a consistent reference displacement to avoid additional calculations related to the various possible paddle spacing. In another example, the user can utilize the clinical application CA and/or user input devices TID on the tensor T itself to lower the upper paddle UP in the displacement control mode DCM. The user-implemented lowering of the upper paddle UP can be regulated by the tensor control system TCS so as to not exceed the predetermined capture displacement. In other words, the user can control the tensor T to lower the upper paddle UP until the tensor control system TCS determines that the auxiliary paddle is sufficiently captured. Thereafter, the tensor control system TCS can disable further movement of the upper paddle UP and/or provide a visual confirmation to the user on a display device that the auxiliary paddle AP has been captured and is ready for use. Such visual guidance can be presented on any of the displays described herein, including the head-mounted display.
To utilize the auxiliary paddle AP to obtain joint measurements in the displacement control mode DCM, the distal portion ADP of the auxiliary paddle AP contacts the bones, and in response, the auxiliary paddle AP will apply force to the upper paddle UP. The displacement or position sensor can measure a resulting displacement between the paddles UP, LP in response to force applied to the upper paddle UP by the auxiliary paddle AP. Alternatively, or additionally, the force sensor S can be utilized to measure a resulting force applied to the upper paddle UP by the auxiliary paddle AP. The tensor control system TCS can utilize the measured displacement and/or force to obtain readings about the joint AJ, such as laxity, stiffness, ligament balance, kinematics, flexion, extension and/or range of motion. In the displacement control mode DCM, the tensor control system TCS can also be configured to control the paddles UP, LP in a manner that places the auxiliary paddle AP (of
To capture the auxiliary paddle AP in the force control mode FCM, the tensor control system TCS commands movement of the upper paddle UP towards the lower paddle LP. This process can be manually guided or automatically implemented. In one example, the tensor control system TCM can automatically lower the upper paddle UP until a predetermined capture force applied to the upper paddle UP by the auxiliary paddle AP is detected or reached. The predetermined capture force can be utilized to prevent overdriving the upper paddle UP onto the auxiliary paddle AP and possibly damaging the system components. The predetermined capture force can be detected by the force sensor S. The predetermined capture force can be indicative of the auxiliary paddle AP being appropriately or sufficiently captured between the paddles UP, LP. For example, the tensor control system TCS can include predetermined data related to the geometry of the auxiliary paddle AP and derive the predetermined capture force from such data. Alternatively, or additionally, the predetermined capture force can be derived from factory measurements based on tests involving capturing of the auxiliary paddle AP. The predetermined capture force can also be a maximum allowable force of the tensor T or any arbitrary force less than the maximum allowable force. In another example, the paddles UP, LP may be automatically placed in a maximum opened position and then the upper paddle UP can be automatically lowered until the predetermined capture force is reached. In another example, the user can utilize the clinical application CA and/or user input devices TID on the tensor T itself to lower the upper paddle UP in the force control mode FCM. The user-implemented lowering of the upper paddle UP can be regulated by the tensor control system TCS so as to not exceed the predetermined capture force. In other words, the user can control the tensor T to lower the upper paddle UP until the tensor control system TCS determines that the predetermined capture force is reached and the auxiliary paddle is sufficiently captured. Thereafter, the tensor control system TCS can disable further movement of the upper paddle UP and/or provide a visual confirmation to the user on a display device that the auxiliary paddle AP has been captured and is ready for use. Such visual guidance can be presented on any of the displays described herein, including the head-mounted display.
To utilize the auxiliary paddle AP to obtain joint measurements in the force control mode FCM, the distal portion ADP of the auxiliary paddle AP contacts the bones, and in response, the auxiliary paddle AP will apply force to the upper paddle UP. The force sensor S can measure a resulting force applied to the upper paddle UP by the auxiliary paddle AP. The tensor control system TCS can utilize the measured force to obtain readings about the joint AJ, such as laxity, stiffness, ligament balance, kinematics, flexion, extension and/or range of motion. In the force control mode FCM, the tensor control system TCS can also be configured to control the paddles UP, LP in a manner that places the auxiliary paddle AP (of
The tensor control system TCS can combine the above-described functions or features of displacement and/or force to capture the auxiliary paddle AP and utilize the auxiliary paddle AP to obtain joint measurements in the force-displacement control mode.
The tensor control system TCS can capture the auxiliary paddle AP in any one of the described modes and utilize the auxiliary paddle AP to obtain joint measurements in any other one of the described modes. The same mode need not be utilized for both purposes. Additionally, the tensor control system TCS can utilize, or switch between, any two modes to capture the auxiliary paddle AP. Also, the tensor control system TCS can utilize, or switch between, any two modes to utilize the auxiliary paddle AP to obtain joint measurements. In other implementations, the upper paddle UP may be pressed down manually by the user to capture the auxiliary paddle AP (without regard to any control mode). Then, the tensor control system TCS can lock the position of the upper paddle UP once the user confirms that the auxiliary paddle AP is captured. In yet another implementation, the tensor control system TCS may simply space the paddles UP, LP apart with just enough space required to receive the auxiliary paddle AP. Then, the user can insert the auxiliary paddle AP while the paddles UP, LP remain in this spaced position.
Referring to
The spacer(s) SP are configured to be removably coupled to any paddle UP, LP. For instance, as shown in
The spacers SP can be of any suitable thickness (e.g., height) and size. For example, the tensor T can be accompanied by a kit of spacers SP of incremental thicknesses (e.g., 2 mm, 5 mm, . . . 20 mm, etc.) and incremental sizes (size 1, 2, 3 . . . 10, etc.). SP of different thickness and/or size can be applied to different paddles, e.g., depending on the desired distraction range. For example, where the tensor T has separate medial and lateral upper paddles, the spacer SP on the medial upper paddle may be different size and/or thickness than the spacer SP on the lateral upper paddle. Additionally, for TKA revision procedures, the spacer(s) SP may be conveniently designed to be augment thickness increments to match the augment bone prep (e.g., the bone removed to make room for an augment implant).
The spacers SP can be of any suitable shape. For example, the spacers SP can be disc shapes or shapes that conform to a shape of the respective paddle. The spacers SP may have substantially flat upper and lower surfaces. In another example, the bone contacting surface of the spacer SP may be curved or contoured to provide an articular surface to enable the contacting bone to rotate on the spacer SP during joint evaluation. The curvature or contouring may be generic or patient-specific and additively manufactured.
The spacers SP can be used during any type of procedure and during any stage of the procedure. For example, for a primary case, the spacers SP can be used to contact native bone surfaces (prior to bone preparation), bone surfaces after preparation, or implant surfaces (after the implants are installed). The spacers SP can be used once both the femoral and tibial surfaces are resected/prepared, or once one of the femoral and tibial surfaces are resected/prepared. In a revision procedure, the spacers SP can be used to contact any of the described surfaces, as well as a primary implant (from a prior procedure). In another example, for primary or revision procedures, the spacer SP can be used to mimic the geometry of a trial implant. In yet another example, instead of attaching to a respective paddle, the spacers SP can be coupled to the (primary or revision) implant itself.
With reference to
Throughout the description of the following methods, it should be understood that the method can be utilized with one tensor body, or with two tensor bodies TB1, TB2. Depending on the configuration of the tensor T, certain steps may be performed on the knee joint once, i.e., with one tensor body TB or with simultaneous action of two tensor bodies TB1, TB2, or the steps could be performed twice, i.e., once for each respective tensor body TB1, TB2. Therefore, although some steps of the method are described in a singular manner for simplicity of description, it is contemplated that these steps can be performed in plural, simultaneous, serial, or parallel manners.
One particularly challenging part of the knee evaluation process involves determining the optimal laxity of the knee joint required to enable the knee to reach full extension (e.g., ˜0 degrees knee flexion). Distracting the knee with any tensor at 0 degrees (full extension) will likely produce inaccurate measurements due to posterior capsule tightness. To assess the tension of the knee at full extension, described herein are enhanced workflows and methods for using the tensor T. The workflows and methods provide a seamless and optional automated or semi-automated assisted process for the surgeon to evaluate the knee extension while also avoiding the surgeon needing to use trial-and-error or educated guesses to adjust the tensor T or evaluate the knee joint. The techniques described herein reduce duration of evaluation process, produce accurate results, and is convenient to the surgeon.
The method 200 includes a first step 202 of controlling, with the tensor control system TCS, the tensor T in the force control mode FCM for applying forces to the knee joint AJ until a predetermined force is reached. In some cases, it is contemplated that the force control mode FCM can be initiated once the paddle(s) contact the bone and some initial force or resistance is measured. For example, the tensor T can be used in a displacement control mode or the paddles can be moved according to a constant velocity until some force or resistance is measured. Thereafter, the tensor T can be operated in the force control mode FCM for applying forces to the knee joint AJ until the predetermined force is reached.
Then, at step 204, the tensor control system TCS captures a plurality of force-displacement data pairs from the tensor T resulting from the tensor T applying forces in the force control mode FCM. At step 206, the tensor T is operated in the displacement control mode DCM by progressively decreasing a displacement of the tensor T according to displacements from the plurality of force-displacement data pairs. Decreasing the displacement can occur until the knee joint AJ can reach the acceptable full extension pose. The knee joint may reach acceptable full extension pose during, or after completion of, the extension test. Specific aspects, implementations, and variations of this method 200 will be described below.
With reference to
At step 302, the navigation system 32 utilizes the localizer 44 to track the femur F and the tibia TIB of the knee joint AJ. This can be performed using aspects of the tracking system described above, e.g., using the anatomical trackers 54, 56, or any other tracking modality. This step 302 is optional but can provide useful information to aid the surgeon in understanding the parameters of the knee joint AJ.
At 302a, the information from the localizer 44 can be utilized to dynamically track a pose of the knee joint AJ. The femur F and tibia TIB can be registered to the navigation system 32. By knowing the respective pose of the femur F and tibia TIB, the navigation controller 36 can compute the relationship between the respective long axes of the bones.
At 302b, the information from the localizer 44 can be utilized to dynamically track a gap of the knee joint AJ. The gap is the spacing or distance between a surface of the femur F and a surface of the tibia TIB. When measuring the gap, the surface of any bone may be resected, non-resected, partially resected. Any resected surface may be smooth (such as a tibial resection) or irregular (such as for a revision procedure). Furthermore, the surface may be an articular surface of the bone or an existing implant in the bone. The articular surface may be a native articular surface (e.g., the native condyles of the femur), or an artificial articular surface (e.g., the artificial condyle components of a femoral implant or a surface of a trial implant). Computing the gap from the surfaces could be based on distal-most point(s) of each surface or could be based on an average taken from certain distal points. The navigation system 34 can record the gap over time, including changes in the gap, and output gap data for display to the graphical user interface GUI. In other cases, the gap can be measured based on virtual surfaces of the bones rather than actual surfaces. For example, 3D virtual models of the bones can be compared to determine the gap of the joint, e.g., at discrete poses or over a range of motion. Implants may be virtually planned relative to the 3D virtual bone models and the gap can be compared relative to the surfaces of the virtual implants. The tracked movements of the bones by the localizer 44 can cause corresponding movements of the virtual bone models and/or virtual implants to evaluate the gap. Any of the described examples of computing the gap can be used individually or in combination.
At step 304, the knee joint AJ is placed in a first acceptable flexion pose. The acceptable flexion pose is a pose of the knee joint between full extension and full flexion, e.g., a mid-flexion or semi-flexion pose. In one example, the first acceptable flexion pose can be a value between 2-15 degrees of knee joint flexion, such as 10 degrees (as illustrated in
The process of placing the knee joint AJ in the any pose described herein (including the first acceptable flexion pose) can be a manual, automated or semi-automated process. When manually performed, the surgeon or technician physically moves the knee joint AJ into the first acceptable flexion pose. At 304b, for example, the navigation system 34, using the graphical user interface GUI, can provide visual guidance to aid the surgeon or technician in placing the knee joint AJ into the first acceptable flexion pose. For example, as shown in
Alternatively, the knee joint AJ can be placed in any pose described herein (such as the first acceptable flexion pose) automatically or semi-automatically. The automated or semi-automated movement may be predefined or set by a surgeon or staff. Parameters of the automated movement can be discrete positions, continuous motions, prescribed manners, target pose(s), target range(s), or the like. An anatomical manipulator, such as a robotically controlled limb holder, may be coupled to the knee joint AJ to provide automated motion at or between different poses. The automated manipulator may reposition and/or re-orient the knee joint AJ in any suitable manner. The anatomical manipulator can include mechanisms for extending or flexing the knee joint AJ. For example, the anatomical manipulator can be supported by a sled, which moves along a support bar. The automated movement may involve moving the sled along the support bar to accomplish a desired movement the knee joint AJ. The anatomical manipulator may also rotate or tilt the knee joint AJ medially or laterally (toward or away from a centerline of the patient). Securing mechanisms can be used for securing the other portions of the leg or knee to the holder. The anatomical manipulator can be locked in any given pose described herein. Of course, the anatomical manipulator may have various other configurations and may be manipulated in various other ways. In another implementation, the manipulator 14 itself is used as the anatomical manipulator. For instance, a limb holder end effector could be attachable to the manipulator 14 to enable movement of the knee joint AJ. Afterwards, the limb holder end effector can be swapped for the end effector 22 to manipulate tissue during the procedure. In this example, the one or more controllers 60, 36, 26 can control the manipulator 14 to move the limb holder end effector in any suitable automated fashion as described. In some instances, the force/torque sensor S can detect forces/torques that are indicative of target poses or target ranges of the knee joint AJ. The one or more controllers 60, 36, 26 can detect these forces/torques to identify that the knee joint AJ has been moved. In other implementations, the one or more controllers 60, 36, 26 can capture and analyze joint encoder data and/or joint motor torque to determine the knee joint AJ has been moved. The anatomical manipulator can be like those described in: US Patent Application Pub. No. 20190262203, entitled “Motorized Joint Positioner”, U.S. Pat. No. 10,390,737, entitled “System and Method of Controlling a Robotic System for Manipulating Anatomy of a Patient During a Surgical Procedure”, and/or U.S. patent application Ser. No. 18/135,280, entitled “Systems and Methods for Guided Placement of a Robotic Manipulator”, the entire contents of each of which are hereby by reference in their entirety.
At step 306, the knee joint AJ has been placed in the first acceptable flexion pose and the tensor control system TCS controls the tensor T in the force control mode FCM to apply forces to the knee joint AJ until a predetermined force. For this step, the force control mode FCM can be automatically triggered by the tensor control system TCS in response to detection of the knee joint AJ being placed in the first acceptable flexion pose. Alternatively, the user may utilize the clinical application CA or the tensor input device(s) TID to selectively activate the force control mode FCM. The process of applying forces to the knee joint AJ can involve both tensor bodies TB1, TB2 of the tensor T. The upper paddle UP of the first tensor body TB1 engages one condyle (medial/lateral) of the femur F and the upper paddle UP of the second tensor body TB2 engages the other condyle (medial/lateral) of the femur F. The lower paddle LP of the first tensor body TB1 and the lower paddle LP of the second tensor body TB2 collectively engage the tibia. In one example, the tibia TIB is resected in a mid-resection workflow. In the force control mode FCM each respective upper paddle is commanded to move until the predetermined force is reached. The predetermined force can be detected by the sensor S within each tensor body TB1, TB2 and recorded by the tensor control system TCS. The applied force will gradually increase until the predetermined force is reached. For the tensor bodies TB1, TB2 commanded movement can be simultaneous or separate. In one example, the predetermined force is a value within the range of 50-150 N, such as 100 N. Other values and ranges of the predetermined force are contemplated. The predetermined force may be the same for both tensor bodies TB1, TB2, or could be different depending on a variety of factors, such as predetermined information about the laxity of the medial/lateral components, or the like. The predetermined force may be reached at the same time, or at various times, for medial and lateral compartments of the knee joint AJ.
At step 308, pursuant to applying the forces at step 306, the tensor control system TCS, optionally in conjunction with the navigation system 34, can capture a plurality of force-displacement data pairs. The process of obtaining these force-displacement data pairs advantageously provides for a testing or sampling of the laxity of the knee joint in a non-fully extended pose instead of the fully extended pose, which presents challenges for evaluating the knee joint. As will be described below, one of the force-displacement data pairs can present an optimal data set for enabling the knee joint to reach full extension. The force-displacement data pairs each include one force measurement and one displacement measurement. For a plurality of discrete forces applied at step 306, a corresponding displacement of the knee joint AJ is captured. In one example, each corresponding displacement value is the displacement between the upper paddle UP and lower paddle LP for each respective tensor body TB. The displacement can be measured using the tensor encoder EN described above. In another example, each corresponding displacement value is the gap of the knee joint as measured by the localizer 44. The force-displacement data pairs can be captured separately for the medial and lateral compartments, e.g., using tensor bodies TB1, TB2. In one example, at 308b, the tensor control system TCS, and/or navigation system 34, can generate a look-up table LUT (as illustrated in
At 308b, the tensor control system TCS, and/or navigation system 34, can capture a target displacement of the tensor T at a time when the predetermined force was reached. The target displacement can be indicative of a target gap of the knee joint. The target gap can be an optimal or preferred gap of the knee joint. As described, the navigation system 34 can utilize the localizer to measure the gap of the knee joint. The target gap may be utilized in a later step (312) during which the extension test is performed.
In
At step 312, with the tensor T being in the displacement control mode DCM, the extension test can begin. The tensor control system TCS can control the tensor T in the displacement control mode DCM to perform the extension test by commanding or changing displacement of the tensor T according to displacements from the plurality of force-displacement data pairs (captured at step 308). In one example, the tensor T progressively decreases (e.g., drops or lowers) the displacement of the upper paddle UP (relative to the lower paddle LP) according to displacements from the plurality of force-displacement data pairs. When two tensor bodies TB1, TB2 are utilized, the tensor T progressively decreases the displacement of the medial upper paddle UP of one body TB and the lateral upper paddle UP of the other body TB, according to respective medial and lateral displacements from the plurality of force-displacement data pairs.
Progressively decreasing the displacement of the upper paddle(s) UP can be performed according to various methods. In one example, at 312a, the tensor T can lower the upper paddle UP according to the specific values of displacement stored in the look-up table LUT. For example, the tensor control system TCS first drops to upper paddle UP to the largest displacement value from the table LUT, then drops the upper paddle UP to the second largest displacement value from the table LUT, etc. The process can continue for each displacement value, in decreasing order, as needed to conclude the extension test. For example, the process can continue until a displacement value is identified that enabled the knee to reach the acceptable full extension pose (as will be described below at 316). Alternatively, the process can continue for each displacement value, in decreasing order, until the last (or smallest) displacement value from the table LUT is reached. When transitioning from one displacement value to the next, the tensor control system TCS can continuously or smoothly transition between displacement values or can wait a predetermined amount of time (e.g., 1 second) between transitions. Advantageously, as will be described below, by lowering the upper paddle UP according to the specific values of displacement stored in the table LUT, the tensor control system TCS can make correlations to the forces in table LUT to make determinations about parameters of knee joint.
Additionally, or alternatively, at 312b, progressively decreasing the displacement of the upper paddle(s) UP can be performed with reference to the target displacement. As described at 308b, the target displacement of the tensor T can be captured at a time when the predetermined force was reached. The target displacement can be indicative of a target gap of the knee joint. Prior to performing the extension test, the tensor control system TCS can control the tensor T in the displacement control mode DCM to place the tensor T at the target displacement and/or perform the extension test by progressively decreasing the displacement of the tensor T starting from the target displacement. Here, the lowering of the upper paddle UP can be progressively decreased (starting from the target displacement) as needed to conclude the extension test. For example, the paddle UP can be lowered according to the displacement values from the data pairs, or until the paddles reached a predetermined state, e.g., a fully closed state.
In one implementation, at 312c, the tensor control system TCS can perform the extension test by automatically decreasing the displacement of the tensor T. In other words, once the extension test is commanded, the tensor T automatically lowers the upper paddle UP according to the displacement from the data pairs (and without further user intervention). The automatic extension test can be triggered through the clinical application CA and/or through user input TID devices on the tensor T itself.
In another implementation, at 312d, the tensor control system TCS can perform the extension test by decreasing the displacement of the tensor T according to user input. The user can utilize the clinical application CA and/or user input TID devices on the tensor T itself to provide input to the tensor control system TCS to drop the upper paddle UP to a first displacement from the data pairs. Once the first displacement is reached, the user provides a subsequent input to the tensor control system TCS to drop the upper paddle UP to the next displacement from the data pairs. This process can be repeated as needed to conclude the extension test.
The process of performing the extension test on the knee joint AJ can involve both tensor bodies TB1, TB2 of the tensor T. The upper paddle UP of the first tensor body TB1 engages one condyle (medial/lateral) of the femur F and the upper paddle UP of the second tensor body TB2 engages the other condyle (medial/lateral) of the femur F. The lower paddle LP of the first tensor body TB1 and the lower paddle LP of the second tensor body TB2 collectively engage the tibia. In one example, the tibia TIB is resected in a mid-resection workflow. In the displacement control mode DCM, each respective upper paddle is commanded to move according to displacement values specifically captured for the respective tensor body and medial and lateral compartments. The commanded displacements can be detected by the encoder EN within each tensor body TB1, TB2 and recorded by the tensor control system TCS. The commanded displacements for the upper paddles UP can be simultaneous or separate. The commanded displacements may be the same for both tensor bodies TB1, TB2, or could be different depending on a variety of factors, such as predetermined information about the laxity of the medial/lateral components, or the like. The acceptable full extension pose can be reached at the same time, or at various times, for medial and lateral compartments of the knee joint AJ.
Pursuant to any variation or combination of techniques described above at step 312, the tensor T displacement is progressively decreased in attempt to assess whether the knee joint AJ to reach the acceptable full extension pose. Hence, the method 300 includes a step at 314 of evaluating whether the knee joint AJ is able to reach the acceptable full extension pose pursuant to the extension test. As described above, the acceptable full extension pose may be a full extension (e.g., ˜0 degrees of knee flexion). Alternatively, depending on the patient soft tissue and bony anatomy, as well as surgeon preferences, and surgical plan, the acceptable full extension pose may not be a completely full extension. For example, the acceptable full extension can be any value within a range of −1 to 5 degrees of full extension.
It is possible that the knee joint AJ is unable to reach the acceptable full extension pose pursuant to the extension test. For example, the ligaments of the knee joint AJ may exhibit flex contracture or hyperextension preventing full extension. If the knee joint AJ is unable to reach the acceptable full extension pose, the method 300 can return to any prior one of step 306, 308, 310, and 312 to re-execute aspects of the method.
For example, if hyperextension is present at step 314, then step 306 can be re-performed, whereby in the first acceptable flexion pose, the tensor can be controlled in the force control mode to apply forces to the knee joint until an incrementally greater predetermined force is reached (as compared with the predetermined force utilized in the first iteration). For example, the greater predetermined force can be chosen to be incrementally higher than the highest force value of the prior look-up table LUT. Based on the greater predetermined force, the captured force-displacement pairs will change and the look-up table LUT will be repopulated (at step 308). Then, steps 310 and 312 can be redone to determine if the knee joint reaches the acceptable full extension pose.
If flex contracture is present at step 314, the input parameters of the extension test can be changed. For example, alternative displacement values from the data-pairs (e.g., from step 308) may be utilized to perform the extension test. The alternative displacement values could be displacement values from the table LUT that were not utilized in the first iteration of the extension test. These displacement values may be, for example, displacement values that are lesser than the smallest displacement value utilized in the first iteration of the extension test. For instance, the first iteration may have utilized, from the table LUT, displacement values of 13, 12.5, 12, 11.5, 10, and 9 mm. On the second iteration, the parameters of the extension test can be modified to lower the range of the displacement values to: 12.5, 12, 11.5, 10, 9, and 8 mm. The alternative displacement values can be from the table LUT or interpolated or predicted based on the previously utilized displacement values using any statistical or mathematical approach, such as linear regression, standard deviation, or the like. The second iteration can then be executed using any variation or combination of the techniques described at step 306, 308, 310 and 312 to determine if the full extension pose can be reached. If the acceptable full extension pose cannot be reached, the surgeon may be required to resect more material from one or both bones prior to re-performing any one of steps 306-312.
If the knee joint AJ is unable to reach the acceptable full extension pose, it is also contemplated that the method 300 can return to step 306 to re-perform the process of applying forces to the knee joint until the predetermined force is reached. Here, the predetermined force can be adjusted. For instance, the predetermined force can be increased or decreased, thereby changing the force-displacement data pair values that will be subsequently captured. The predetermined force can also be computed or predicted based on the force values from the table LUT. For instance, the predetermined force can be increased by a default value of 10%. In another example, the predetermined force may be computed, or predicted, based on the smallest displacement value utilized in the first iteration of the extension test.
Ideally, as a result of the methodical considerations described herein, the knee joint AJ should be able to reach the acceptable full extension pose pursuant to performing the extension test only one time. If so, the method 300 proceeds to step 316. At 316, during, or after completion of, the extension test, the tensor control system TCS can identify a first force-displacement data pair that enabled the knee joint AJ to reach the acceptable full extension pose. In other words, when the knee joint AJ reaches the acceptable full extension pose, it would have reached so according to a commanded displacement by the tensor T, wherein the commanded displacement includes a corresponding force value. The first force-displacement data pair includes the value of the displacement that enabled the knee to reach the acceptable full extension pose, as well as the force value corresponding to the displacement value. The term “first” with respect to first force-displacement data pair is merely used to distinguish this data pair from others that will be described below. The term “first” is not limited to mean that the data pair is the initial or first data pair in a list of data pairs.
In
At 318a, the navigation system 34, using the graphical user interface GUI, can provide visual guidance to aid the surgeon or technician in placing the knee joint AJ into the second acceptable flexion pose. For example, as shown in
At step 320, when the knee joint AJ is in the acceptable full extension pose, the tensor control system TCS switches control of the tensor T from the force control mode FCM to the displacement control mode DCM. Here, the tensor control system TCS controls the tensor T in the force control mode FCM to apply a second predetermined force to the knee joint when the knee joint is in a second acceptable flexion pose. The term “second” with respect to second predetermined force is merely utilized to distinguish from the predetermined force applied in step 306. The term “second” effectively means “another” force and is not limited to specifically mean the second force in a sequence of forces.
For step 320, the force control mode FCM can be automatically triggered by the tensor control system TCS in response to detection of the knee joint AJ being placed in the second acceptable flexion pose. Alternatively, the user may utilize the clinical application CA or the tensor input device(s) TID to selectively activate the force control mode FCM. The process of applying the second predetermined force to the knee joint AJ can involve both tensor bodies TB1, TB2 of the tensor T. The upper paddle UP of the first tensor body TB1 engages one condyle (medial/lateral) of the femur F and the upper paddle UP of the second tensor body TB2 engages the other condyle (medial/lateral) of the femur F. The lower paddle LP of the first tensor body TB1 and the lower paddle LP of the second tensor body TB2 collectively engage the tibia. In one example, the tibia TIB is resected in a mid-resection workflow. In the force control mode FCM each respective upper paddle is commanded to move until the second predetermined force is reached. The second predetermined force can be detected by the sensor S within each tensor body TB1, TB2 and recorded by the tensor control system TCS. The applied force will gradually increase until the second predetermined force is reached. For the tensor bodies TB1, TB2 commanded movement can be simultaneous or separate. The second predetermined force may be the same for both tensor bodies TB1, TB2, or could be different depending on a variety of factors, such as predetermined information about the laxity of the medial/lateral components, or the like. The second predetermined force may be reached at the same time, or at various times, for medial and lateral compartments of the knee joint AJ.
The second predetermined force that is applied at step 320 can be derived or obtained from various sources. At 320a, the tensor control system TCS can obtain the second predetermined force from a force value of the first force-displacement data pair that enabled the knee joint to reach the acceptable full extension pose (at step 316). Advantageously, by using the force from the first force-displacement data pair, the knee joint can be tensioned in the second acceptable flexion pose using a force value that was captured (but not applied) while the knee was in the acceptable full extension pose. The process of extracting this force value from its corresponding displacement value avoids having to forcibly distract the knee joint with the tensor T in the full extension pose. In turn, the force value is an accurate measurement that is not subjected to inaccuracies resulting from posterior capsule tightness in the fully extended pose. Alternatively, or additionally, at 320a, the tensor control system TCS can obtain the second predetermined force from a predetermined joint balancing force, a force based on a surgeon preference, a force obtained from statistical data, or any force from any of the force-displacement data pairs.
At step 322, pursuant to applying the second predetermined forces at step 320, the tensor control system TCS, optionally in conjunction with the navigation system 34, can capture or identify a second force-displacement data pair. The process of obtaining the second force-displacement data pair advantageously provides for a testing or sampling of the laxity of the knee joint in the second acceptable flexion pose. The term “second” with respect to second force-displacement data pair is merely utilized to distinguish from the first force-displacement data pair identified in step 316. Here, the term “second” effectively means “another” force-displacement data pair and is not limited to specifically mean the second data pair in a sequence or table of data pairs. The second force-displacement data pair includes one force measurement and one displacement measurement. The second force-displacement data pair can include a force component that is the second predetermined force that was applied at step 320. Alternatively, the second force-displacement data pair can include a force component that is different, or less than, the second predetermined force that was applied at step 320. The displacement component of the second force-displacement data pair can be the displacement of the knee joint AJ that was reached pursuant to the second predetermined force applied at step 320. The displacement can be derived from the displacement of the upper paddle UP and/or derived from the gap of the knee joint as measured by the localizer 44 tracking the bones. At step 322, it is contemplated that the tensor control system TCS, and/or navigation system 34, can generate another look-up table LUT (similar to that illustrated in
At step 324, the tensor control system TCS, and optionally in conjunction with the navigation system 34, can determine parameters of the knee joint AJ based on (1) the first force-displacement data pair (from step 316) that enabled the knee joint to reach the acceptable full extension pose and based on (2) the second force-displacement data pair (from step 322) identified while the knee joint was at the second acceptable flexion pose. The parameters can be laxity, stiffness, ligament balance, kinematics, flexion, extension and/or range of motion of the anatomical joint AJ. The parameters can be laxity of medial and lateral compartments of the knee joint. For instance, the two force-displacement data pairs can provide four laxity data points (two force and two displacement) defined in the range of full extension to full or near full flexion (90-120 degrees).
The method 300 described with reference to
Additionally, and with reference to
At step 400, the knee joint AJ is placed in the second acceptable flexion pose (e.g., ˜90 degrees) and the tensor control system TCS controls the tensor T in the force control mode FCM to apply a predetermined force to the knee joint AJ. At step 404, the tensor control system TCS, and optionally in conjunction with the navigation system 34, captures a first set of force-displacement data pairs resulting from the forces applied at step 402. These data pairs are stored for later use in the method 400. For example, as described above, the first set of force-displacement data pairs can be stored in a look-up table LUT. At step 406, the knee joint AJ is placed in the first acceptable flexion pose (e.g., 10 degrees) and the tensor control system TCS controls the tensor T in the force control mode FCM to apply forces to the knee joint AJ until a predetermined force is reached. This predetermined force can be the same as, or different from, the predetermined force applied at step 402. Either of these predetermined forces can be obtained from a predetermined joint balancing force, a force based on a surgeon preference, a force obtained from statistical data, or any force from any of the force-displacement data pairs. At step 408, the tensor control system TCS, and optionally in conjunction with the navigation system 34, captures a second set of force-displacement data pairs resulting from the forces applied at step 406. The second set of force-displacement data pairs may or may not have values that correspond to the values from the first set of force-displacement data pairs. At step 410, while the knee joint AJ remains in the first acceptable flexion pose (e.g., 10 degrees), the tensor control system TCS can switch operation of the tensor T to the displacement control mode DCM to perform the extension test. Here, the tensor T displacement is progressively decreased according to the displacement values from the second set of force-displacement data pairs. Similar to step 314 described above, an evaluation can be made regarding whether the knee joint was able to reach the acceptable full extension pose. Assuming the knee joint reaches the acceptable full extension pose, at step 412, the tensor control system TCS, and optionally in conjunction with the navigation system 34, identify a force-displacement data pair from the second set that enabled the knee joint to reach the acceptable full extension pose. At step 414, the tensor control system TCS, and optionally in conjunction with the navigation system 34, utilizes the force-displacement data pair from the second set to identify a force-displacement data pair from the first set (at 404). For example, the force and/or displacement value from the force-displacement data pair of the second set can be correlated, compared, or otherwise evaluated relative to force and/or displacement values from the first set. This process can be performed by comparing the rows or columns of the tables LUT to identify identical or substantially similar force or displacement values. Effectively, just like method 300 described above, the method 400 can utilize the two force-displacement data pairs to obtain four laxity data points (two force and two displacement) defined in the range of full extension to mid-flexion or full flexion. The method 400 can also be utilized to determine any other described parameters of the knee joint AJ.
Described herein are techniques for compensating for mechanical deflection of any paddle(s) of the tensor T in response to an applied load. For example, during execution of any of the described workflows, there is a possibility that one or more of the upper paddles UP in contact with a femoral condyle(s) can deflect mechanically. The deflection in the paddles is linear and can be measured. The measured displacement or force of the tensor T as observed by the sensors in the tensor T, can be compensated by predicting the corresponding deflection of the paddle(s) because the load experienced by the actuators of tensor T is a known quantity. For instance, when the extension pose is captured, the tensor T can be operated in position control mode. The force that is recorded for the extension pose can be determined using a lookup table that records a force-position mapping. The look up table can be configured to provide predicted paddle deflection. The look up table can be paddle specific and can correlate force on the paddle to deflection of the paddle. For example, for every N Newtons of force applied to the paddle, the paddle will deflect D mm from its at-rest state. Again, this mapping is based on a linear relationship between force and deflection. In other configurations, the look up table can be configured to provide a predicted distraction/force table for the tensor T, which is based on the predicted paddle deflection. The look up table can be stored in any appropriate non-transitory memory, such as one located in the tensor T or tensor body TB, or one located remote from the tensor.
During the surgical workflow, the commanded/measured force and/or distraction of the tensor T is captured. Suppose the commanded distraction is 9.5 mm at 95N of force. Using the values of the commanded/measured force and/or distraction, the look up table can be referenced to obtain a predicted deflection of the paddle or predicted distraction/force values. Suppose for 95N of force, the look up table provides a value of 1.5 of paddle deflection. Based on this, the controller(s) can adjust the commanded/measured distraction by the referenced deflection (e.g., 9.5 mm minus 1.5 mm) to produce a compensated final distraction value (or predicted distraction) of 8 mm that compensates for the paddle deflection resulting from the force. From here, a predicted force value can be obtained that corresponds to the predicted deflection value. For example, instead of the actual recorded 95N of force based on 9.5 mm of distraction, the predicted force can be adjusted to 85N based on 8.0 mm predicted distraction.
This paddle deflection compensation technique can be applied for force measurements or displacement measurements and can be applied for the force control mode, displacement control mode, and/or force-displacement control mode. Furthermore, paddle deflection compensation can be applied at any one or more steps of the described workflows 300, 400, or at the end of any of the described workflows (e.g., after all requisite measurements are recorded). The predicted values can be informed to the surgeon using a visual indicator (or new table column) on the software application (e.g., as a new column shown in the look up table LUT of
The tensor T has been described in some examples above using a configuration whereby the upper paddle UP engages the femur and the lower paddle LP engages the tibia. In these examples, the lower paddle LP usually remains stationary and the upper paddle UP moves relative to the lower paddle LP. It is contemplated that this tensor T can be used in an alternative manner. For example, referring to
In another example, as shown in
In another example, the tensor T may be configured such that a portion of the tensor body TB (e.g., the handle or gripping features G) is configured to swivel or pivot relative to the paddles or relative to the portion of the tensor body TB that includes the displacement mechanism DM for the paddles. The pivoting or swiveling of the moveable portion of the tensor body TB can enable the tensor body TB to have an inverted configuration, as described in
Any of the features or configurations of the tensor T described in the prior sections can be fully implemented for the inverted use or inverted configuration of the tensor T described herein. For example, it is contemplated that both paddles UP, LP may move in the inverted use or inverted configuration of the tensor T, and the like.
Several embodiments have been described in the foregoing description. However, the embodiments discussed herein are not intended to be exhaustive or limit the invention to any particular form. The terminology, which has been utilized, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations are possible in light of the above teachings and the invention may be practiced otherwise than as specifically described.
In reference to the disclosure provided above, for purposes of convenience and clarity only, directional terms such as top, bottom, above, upper, lower, proximal, distal, vertical, horizontal, etc., are used with respect to the context of the accompanying drawings and will be understood by those skilled in the art with respect to such context. Such directional terms used in conjunction with the following description of the drawings should not be construed to limit the scope of the invention in any manner not explicitly set forth. Additionally, the term “a,” as used in the specification, means “at least one.” The terminology includes the words above specifically mentioned, derivatives thereof, and words of similar import.
The subject application claims priority to and all the benefits of U.S. Provisional Patent App No. 63/524,241, filed Jun. 30, 2023, the entire contents of which are hereby incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63524241 | Jun 2023 | US |
