Patent Application
20180333096
The disclosure generally relates to robotic knee testing and evaluation, and more particularly to a thigh immobilizer for use with a robotic knee testing apparatus and a method of using a thigh immobilizer.
The knee joint is composed of the femur or thigh bone, the tibia or shin bone, and the patella or knee cap. The bones are connected by fibrous structures called ligaments, which allow a certain amount of “joint play” or motion to exist between the bone structures. When this joint play is increased or decreased, an abnormal or pathological condition exists in the knee. Attempts have been made in the past to quantify this increase or decrease in joint play of the knee with limited success.
Knee injuries often cause damage to one or more of the structures that form the knee joint. Such injuries typically cause an increase in joint play or motion of the knee. A patient may interpret an increase in joint play as a sensation that the knee is slipping or coming out of joint. In other words, this sensation may be described by the patient as the feeling of joint instability. Knee instability may be related in part to an increase in the length of the ligaments that connect the bones together, an increase or change in compliance (elastic resilience or stretchiness) of the ligaments, or both. Knee instability may also be related in part to the shape and size of the joint bones. The degree or likelihood of the knee joint bones actually coming out of joint or becoming unstable is related to the amount of stretch or increased length of each knee ligament, the number of knee ligaments involved, and the existence of damage to one or more other support structures of the knee joint, such as the joint bones themselves, the menisci, or the like. Accurate measurement of an increase in ligament length can be critical to restoring a patient's injured or damaged knee to as close as possible to its original functional and anatomical structure and condition.
For the most part, knee injuries and ligament damage have been diagnosed using only manual tests. These tests are performed by doctors or other medical personnel, i.e., clinicians, on the patient in order to detect and measure joint play to diagnose damage to the knee ligaments or other knee joint support structures. There are a number of commonly known manual tests used to evaluate increased joint play, which is usually associated with an anterior cruciate ligament (ACL) tear. These tests include the Lachman's test, the Pivot Shift test, and the Anterior Drawer Test. Because these tests are performed manually by individual medical personnel, these tests naturally are limited by the specific clinician's subjective evaluation. The subjective nature of the tests may hinder the precision or accuracy of any diagnosis of the extent of ligament lengthening, the change in ligament compliance or elastic resilience, i.e., stretchiness, or both.
The Lachman's test is performed with a patient lying in a supine position. The clinician will bend the patient's knee joint at approximately 20 to 30 degrees. The clinician places one hand on the patient's upper thigh and their other hand below the upper part of the patient's calf. The clinician then applies upward pressure under the patient's calf and downward pressure on the patient's thigh. This induces a translation between the patient's femur and tibia. The degree of translation is subjectively determined by the clinician to diagnose the injury or joint damage.
The Pivot Shift test is similarly performed with the patient lying in a supine position. The leg is straightened out so that the knee joint is placed in full extension (x-axis rotation). A valgus or side-to-side outward rotation (y-axis rotation) force and an internal or twisting rotation (z-axis rotation) force is applied to the knee to allow the lateral tibia to slip anteriorly from underneath the lateral femoral condyle. As the knee is flexed or bent (x-rotation), the tibia is allowed to slip suddenly back underneath the femoral condyle. The clinician subjectively determines whether there is an abnormal external rotation (z-axis rotation) and posterior translation (y-axis translation) of the tibia with respect to the femur. The degree of shift that is felt or determined by the clinician represents to the clinician the relative increased translation (y-axis translation) of the lateral side of the knee with respect to the increased translation (y-axis translation) of the medial side of the knee. A sudden shift in the knee joint is felt by the clinician and represents the point at which the tibia bone slides from in front of the radius of curvature of the curved end of the femur back to its normal position under the femoral condyle. The clinician then subjectively rates the pivot shift as Grade I, Grade II, or Grade III depending upon the degree of rotational and translational shift felt during the test. The Pivot Shift test is inherently subjective, difficult to accurately perform, difficult to teach, and ultimately difficult to quantify.
The Anterior Drawer test is also performed with the patient lying in a supine position, but with the knee joint bent to about 90 degrees (x-axis rotation). The patient's foot is supported by a table or chair while the clinician applies thumb pressure to the knee joint. The Anterior Drawer test is subjectively graded by the clinician based on the perceived amount or extent of anterior translation of the tibia with respect to the femur. A Grade I injury is determined as having about 5 mm or less of anterior translation. A Grade II injury is determined as having between about 6 to 10 mm of anterior translation. A Grade III injury is determined as having between about 11 to 15 mm of anterior translation.
In order for a clinician to diagnose an injured ACL using the aforementioned manual tests, the clinician must determine whether the knee feels “abnormal.” The accuracy of an ACL injury diagnosis provided by a clinician using currently known manual tests depends on the skill and experience of the clinician and their subjective determinations. A misdiagnosis can lead to unnecessary treatment or unnecessary delay in treatment, which may result in an increased risk for further injury or damage to the patient's knee joint.
There are also manual tests for the lateral collateral ligament (LCL), medial collateral ligament (MCL), and posterior cruciate ligament (PCL). Each manual test relies on grading the degree of length increase in the ligament based on relative increase in joint play into three Grades or categories. There is no effort to grade the compliance or elastic resilience, i.e., stretchiness, of the ligaments using these manual tests. However, an expert clinician may describe the ligament in terms of its subjective feel to the clinician. Also, a knee joint may have injury or damage to more than one ligament or structure. The more ligaments and structures of the knee joint that are damaged, the more complex it is for the clinician to perform a manual knee examination. This can make the diagnosis less accurate and less precise.
Clinicians and surgeons manually examine the injured knee joint for altered or increased joint play. However, due to the variability in size of the patient, size and experience of the surgeon, and the potential degree or subtlety of an injury, consistent and reproducible reports of joint play between surgeons is not possible. Many reports have documented that, whether diagnosis is performed manually or even with manual arthrometers, the manual application of torque to the knee joint varies widely between clinicians. This results in inconsistencies in the examination of joint play.
Others have attempted to reduce the manual nature of such joint tests and to instrument the knee joint during testing. The objective has been to mechanically or objectively quantify or measure a change in the structure of the knee after ligament damage. Several devices have been developed in attempting to more accurately quantify the extent of injury or relative displacement and compliance of a ligament in the knee. In one example, such devices have been developed by Medmetric Corp. These devices include the KT-1000 and KT-2000 models (hereinafter “KT”). The KT devices are intended to measure the anterior-posterior translation of the tibia with respect to the femur along the y-axis. The KT devices attach to the patient's tibia during testing.
The KT devices attempt to quantify the findings achieved by a clinician performing the Lachman's test and the Anterior Drawer Test. Force is applied to a handle on the device, which measures the force and delivers the amount of applied force to the clinician using sounds, such as a low pitched sound for a 15-pound force and a higher pitched sound for a 20-pound force. The applied force in the KT devices pulls anteriorly along the y-axis through a strap that wraps underneath the patient's calf. The translation is determined using a technique that measures the relative motion between a pad placed against the anterior tibia and a pad placed against the patella. The KT devices do not measure relative displacement or compliance in any of the other degrees of freedom in the knee. Also, quantified results from using the KT devices have not been correlated with patient satisfaction. In contrast, the subjective Pivot Shift test has been correlated with patient satisfaction.
Other devices are also known and include the Stryker KLT, the Rolimeter, and the KSS system. These known devices use similar mechanisms to attempt to quantify the normal amount of joint play or motion between the femur and tibia in the knee joint, as well as any increased joint play or motion in the joint associated with ligament lengthening and damage. The applicant of the instant application has developed robotic knee testing (RKT) apparatuses, the basics of which are disclosed and described in U.S. publication nos. 2012/0046540 and 2014/0081181. Each apparatus in part, utilizes motors to perform knee movements during testing and sensors to measure degree of relative movement of the structures in the knee joint. During these tests, portions of the leg of the patient must be kept still and in a fixed manner. The thigh can be clamped using a thigh immobilizer to hold the femur still during testing. However, during use of other existing thigh stabilizers, adjustment of the stabilizers can be difficult. This has resulted in pressure to the lateral and medal portions of the thigh being unequal and insufficient. Testing using a robotic knee testing apparatus without securely holding the femur in a fixed position can reduce accuracy in the test results.
In one example according to the teachings of the present invention, a robotic knee testing apparatus can include a robot configured to manipulate a lower leg of a patient relative to a thigh joined to the lower leg at a knee to be tested. The robotic knee testing apparatus also includes a thigh immobilizer including a first clamping element configured to engage a lateral portion of the thigh, and a second clamping element spaced apart from the first clamping element, the second clamping element configured to engage a medial portion of the thigh. The first clamping element and second clamping element are each configured to move and lock independent of one another. The thigh immobilizer clamps and holds the thigh between the first and second clamping elements when the first clamping element and second clamping element are locked during manipulation of the lower leg.
In one example, the first clamping element of the robotic knee testing apparatus can include a first locking mechanism and the second clamping element includes a second locking mechanism.
In one example, the first locking mechanism of the robotic knee testing apparatus can include a first actuator including a first handle operable to lock and release the first locking mechanism and the second locking mechanism can include a second actuator including a second handle operable to lock and release the second locking mechanism.
In one example, the first locking mechanism and second locking mechanism of the robotic knee testing apparatus can each include an actuator configured to lock and release the first locking mechanism and second locking mechanism independent of the other.
In one example, the first clamping element of the robotic knee testing apparatus can include a first truck and a first paddle connected thereto and the second clamping element can include a second truck and a second paddle connected thereto.
In one example, the first and second trucks of the robotic knee testing apparatus are independently slidable along a locking bar when either of the first or second elements are in an unlocked position to adjust the side-to-side position of, and spacing between, the first and second clamping elements.
In one example, the robotic knee testing apparatus can include first and second paddles that each have a peg or pin at one end and corresponding first and second trucks each can include a plurality of bores spaced apart across the width of the truck, and the first paddle can be removably insertable into a selected one of the plurality of bores in the first truck and the second paddle can be removably insertable into a selected one of the plurality of bores in the second truck to further adjust the side-to-side position of, and spacing between, the first and second paddles.
In one example, the robotic knee testing apparatus can have the first clamping element including a first locking mechanism associated with the first truck and the second clamping element including a second locking mechanism associated with the second truck.
In one example, the robotic knee testing apparatus can include a first slide lock of the first locking mechanism being slidably connected to a locking bar and a second slide lock of the second locking mechanism being slidably connected to the locking bar.
In one example, the first and second locking mechanisms of the robotic knee testing apparatus can each include an actuator connected to a slide plate that, when actuated, move to compress a respective spring within each of the first and second locking mechanisms to release a corresponding pin acting on a locking bar to unlock the first and second clamping elements.
In one example, the thigh immobilizer of the robotic knee testing apparatus can further include a mounting block carried by a portion of the robotic knee testing apparatus and a locking bar coupled to the mounting block. The first clamping element and second clamping element are each slidable relative to the locking bar and the mounting block.
In one example, the first clamping element and the second clamping element of the robotic knee testing apparatus can each include a slide lock situated within a portion of a locking plate to move and lock the first clamping element and the second clamping element independent of one another. Each slide lock can include a slide plate retaining a pin and a spring within the portion of the locking plate.
In one example according to the teachings of the present invention, a thigh immobilizer for use with a robotic knee testing apparatus configured to manipulate a lower leg of a patient to evaluate a knee joint joined to the lower leg can include a first clamping element configured to engage a lateral portion of the thigh and a second clamping element spaced apart from the first clamping element. The second clamping element can be configured to engage a medial portion of the thigh. The first clamping element and the second clamping element can each be configured to move and lock independent of one another. The thigh immobilizer can clamp and hold the thigh between the first and second clamping elements when the first clamping element and second clamping element are locked during manipulation of the lower leg.
In one example, the first clamping element and the second clamping element of the thigh immobilizer can each include a slide lock situated within a portion of a locking plate to move and lock the first clamping element and the second clamping element independent of one another. Each slide lock can include a slide plate retaining a pin and a spring within the portion of the locking plate.
In one example, the first clamping element and the second clamping element of the thigh immobilizer can move toward one another along a locking bar whether locked or unlocked, cannot move away from one another when locked, and can move away from one another when unlocked.
In one example, the thigh immobilizer can include the first clamping element having a first locking mechanism and the second clamping element having a second locking mechanism.
In one example according to the teachings of the present invention, a method of immobilizing a thigh of a patient during a knee examination using a robotic knee testing apparatus includes the steps of placing a patient adjacent a robot of the robotic knee testing apparatus, positioning a thigh of a patient between first and second clamping elements of a thigh immobilizer, adjusting the side-to-side position of, and spacing between, the first and second clamping elements by moving the first and second clamping elements independent of one another and sideways toward one another to a clamping position against the medial and lateral sides of the thigh, retaining the first and second clamping elements in the clamping position, and manipulating the lower leg of the patient using the robot of the robotic knee testing apparatus as the thigh is immobilized by the thigh immobilizer.
In one example, the method can include the step moving the first and second clamping elements toward one another while in a locked state. The step of retaining can include the first and second clamping elements being prevented from moving sideways away from one another being prevented in the locked state.
In one example, the method can include the step of upon reaching the clamping position, a pin of a first locking mechanism of the first clamping element engaging a locking bar and a pin of a second locking mechanism engaging the locking bar so as to prevent the first and second clamping elements from moving sideways away from one another.
In one example, the method can include the step of releasing the first and second clamping elements from a locked state to permit moving the first and second clamping elements sideways away from one another.
Objects, features, and advantages of the present invention will become apparent upon reading the following description in conjunction with the drawing figures, in which:
The disclosed thigh immobilizer and robotic knee testing (RKT) apparatus (i.e., one form of a joint manipulation and evaluation device) solve or improve upon one or more of the above noted and/or other problems and disadvantages with prior known thigh clamps. In particular, the disclosed thigh immobilizer has two thigh clamping elements and allows for independently adjusting the clamping elements on the medial and lateral sides of the patient's thigh. The disclosed thigh immobilizer allows for each of the clamping elements to apply equal pressure to the medial and lateral portions of the thigh. The disclosed thigh immobilizer is configured so that the clamping elements are lockable in an infinite number of positions relative to one another. These and other objects, features, and advantages of the present disclosure will become apparent to those having ordinary skill in the art upon reading this disclosure.
Turning now to the drawings,
The RKT apparatus 50 of
As shown in
As will be evident to those having ordinary skill in the art, the configuration and construction of the table assembly 52 and step 57 can vary considerably from the example disclosed, illustrated, and briefly described herein. The base 56 and/or the patient platform 58 and step base 61 and/or tread 59 can each be altered in configuration, size, shape, orientation, height, construction, materials, and the like. The base 56 and step 57 can include multiple legs and frame elements that are assembled or connected to one another, as in the illustrated example. Alternatively, the base 56 and/or step 57 can be formed as one unitary support element. The patient platform 58 and/or step base 61 can also be formed of multiple components and can be fastened to or otherwise attached to the base. Alternatively, the patient platform 58 and/or step base 61 can be an integral, one-piece fabricated structure and can be fabricated as part of the base or attached thereto. The patient support need not be a table, but instead can be a chair, a suspension system, or other suitable structure that is capable of properly positioning and retaining a patient relative to the robot 54 for testing and examination. The table assembly 52 and/or step 57 can further include additional features, though not disclosed or described herein, that may be used to assist in the patient sitting on the patient platform to assist in positioning a patient on the patient platform, to assist in maintaining a patient's position on the platform, or to otherwise enhance patient comfort or improve performance of the table assembly, the RKT apparatus, or both.
With reference to
In the disclosed example and with reference to
As depicted in
In the example shown in
The knee stabilizer 74 acts as a knee or patellar clamp and can include a framework 76 arranged to surround and clamp onto a patient's joint or knee. The knee stabilizer 74 in this example has a pair of patellar clamping elements 78 that are vertically spaced apart and adjustable relative to one another along the framework 76. The patellar clamping elements 78 can be vertically adjusted in order to clamp or otherwise securely hold the lower end of a patient's right femur and patella in a substantially fixed vertical position during testing, evaluation, or treatment, as described below. If the knee stabilizer 74 is positionally adjustable, it should be capable of being secured in a fixed selected position, once properly adjusted for a given patient, relative to the table assembly 52 and/or robot 54 during testing. The configuration and construction of the knee stabilizer 74 can vary considerably from the example shown herein. The patellar clamping elements 78 can be replaced by other suitable securing or clamping devices or elements and the mechanisms to adjust and secure the knee stabilizer 74 can also vary.
The knee stabilizer 74 can include a plurality of substantially rigid and/or resilient pads 79, such as on the upper and lower patellar clamping elements 78. The pads 79 can be configured and arranged to lie adjacent the patient's knee, preventing the framework 76 and the patellar clamping elements 78 from directly contacting the patient's knee. The pads 79 can be solid, hollow, pressurized, hydraulically filled, pneumatically filled, or the like and can be rubber, foam, or otherwise formed of suitable materials. In one example, the pad or pads 79 on the upper patellar clamping element 78 can be configured to define a V-shape within the framework 76. The patient's leg can then be captured within the V-shape as the upper and lower patellar clamping elements 78 are drawn toward one another to capture and hold still the patient's leg during a procedure.
The thigh immobilizer 70 and/or the knee stabilizer 74 may be mechanically adjustable to manually fit and accommodate different sized patients. In one alternative, the thigh immobilizer 70 and/or the knee stabilizer 74 may be electrically operable to adjust the femur clamping elements 72, the patellar clamping elements 78, respectively, or both. In another alternative example, the femur clamping elements 72 and/or the patellar clamping elements 78 may be pneumatically or hydraulically operable to adjust the thigh and knee stabilizers 70 and 74. In yet another alternative, the thigh immobilizer 70, the knee stabilizer 74, or both, may include two or more such systems or mechanisms for adjusting the respective clamping elements.
The thigh immobilizer 70 and/or femur clamping elements 72 and the knee stabilizer 74 and/or framework 76 and patellar clamping elements 78 can be formed of metal, plastic, or other suitable materials. The thigh immobilizer and knee stabilizer 70 and 74 can vary in shape, configuration and construction, as desired. The thigh and knee stabilizers 70 and 74, in combination, are intended to secure a patient's leg in order to hold the femur and patella in a vertically (knee stabilizer) and side-to-side (thigh immobilizer) fixed position during a test, evaluation, or treatment cycle. Features and aspects of the disclosed thigh and knee stabilizers 70 and 74 can vary considerably while accomplishing this objective. As noted above, further details regarding the thigh immobilizer 70 are described below.
In this example as shown in
As depicted in
As depicted in
In general, the tibia positioning assembly 90 has a foot holder, i.e., a foot plate 92 in this example with a heel stop 93 at the bottom edge of the foot plate that faces upward and has a contact surface 94 that faces toward the thigh and knee stabilizers 70 and 74. The tibia positioning assembly 90 also has a tibia rod device 96 with one or more rods 98 and a calf plate 100 at or near a distal end of the tibia rod device. The one or more rods 98 can be lengthwise adjustable. In this example as shown in
With reference to
In other examples, the RKT apparatus may be configured to test only one or two of anterior-posterior motion, Varus-valgus motion, or tibial rotation, instead of all three tests. In such cases, the drive system may include only one or two of the X-axis, Y-axis, or Z-axis drives instead of all three drives. The methods and procedures described herein may be modified to accommodate such robots that have fewer than all three drives. In other examples, the X-Y-Z axes of the aforementioned coordinate systems may all intersect with one another and may all be orthogonal to one another. In still other examples, none or only two of the axes may intersect and/or none or only two of the axes may be orthogonal to one another.
As shown in
With reference to
The motor 110 and/or gearbox 112 can be designed to produce a limited range of travel, which may be substantially less than 360 degrees of rotations, in the output shaft 114. In addition or in the alternative, the X-axis drive 104 can also be designed to incorporate a mechanical travel limiter, if desired. In one example as shown in
The above-described anterior-posterior movement components of the tibia positioning assembly 90 can vary considerably from the example shown and described herein. The yoke assembly 122 and stop bracket 128 can be eliminated or can take on different positions, configurations, and constructions. Instead, other mechanical stop mechanisms can be employed. Likewise, the configuration and construction of the drive links 116, cross-plate 120, tibia rods 98, and calf plate 100 can also be varied. The mechanisms or devices that are used to secure a patient's leg to the tibia rods 98 and to the foot plate 92, if and when needed for testing, can also vary.
As shown in
As represented in
The motor 140 and/or gearbox 142 can be designed to produce a limited range of travel, which may be substantially less than 360 degrees of rotations, in the output shaft 144. In addition or in the alternative, the Y-axis drive 106 components can also be designed to incorporate a mechanical travel limiter, if desired, though not shown or described herein.
The above-described Varus-valgus movement components of the tibia positioning assembly 90 can also vary considerably from the example shown and described herein. The sled assembly 86, pivot plate 150, and support brackets 154 can be eliminated or can take on different positions, configurations, and constructions. The mechanisms or devices that are used to secure a patient's leg to the tibia rods 98 and to the foot plate 92, if and when needed for testing, can also vary.
As shown in
As represented in
The motor 160 and/or gearbox 162 can be designed to produce a limited range of travel, which may be substantially less than 360 degrees of rotations, in the output shaft 164. In addition or in the alternative, the Z-axis drive 108 components can also be designed to incorporate a mechanical travel limiter, if desired. A simple mechanical stop can be positioned to stop movement of the foot plate 92 in either rotation direction, if desired. Such a stop can be the tibia rods 98 or something mounted thereto. Alternatively, such a stop can be applied to the motor mounting bracket 166 or the like.
The above-described rotation movement components of the tibia positioning assembly 90 can also vary considerably from the example shown and described herein. The foot plate 92 and motor mounting bracket 166 can be eliminated or can take on different positions, configurations, and constructions. The mechanisms or devices that are used to secure a patient's leg to the foot plate 92, if and when needed for testing, can also vary.
The above described motors, gearboxes, and output shafts can also vary within the scope of the disclosure. The motors can be servo-motors or other types of motors suitable for precise motion and torque control and for the loads to which the motors will be exposed during such limb testing and evaluation. Any of the first, second, or thirds, i.e., the X-, Y-, or Z-axis drives with respect to the motors and gearboxes can be structurally configured substantially the same relative to one another, with the only substantive difference being the relative axis of rotation about which each is oriented. Alternatively, each drive can incorporate a motor and/or gearbox that is different than one or both of the others as well. The torque transducers can be selected in order to provide torque readings as known in the art relating to each of the three drives. In other examples, one or more of the torque transducers may be replaced with other torque or load sensors or load sensing means. For example, motor current may be measured to determine the torque or load on the motor output shaft during use. Any suitable means for modeling torque may be used. The torque readings can be calibrated and calculated as needed to correspond to known torque or force values imparted to a patient's limb(s). Movement of the patient's body parts may be detected by non-invasive systems, as noted above, that utilize sensors or markers that are attached to the skin, including but not limited to vision, optoelectronic, ultrasonic, and electromagnetic motion analysis systems.
In use, a patient lies on the padded surface 60 of the patient platform 58 on the table assembly 52 as shown in
Any one of the X-, Y-, and Z-drives can be decoupled from any of the other two. In the disclosed example, each of the three drive assemblies may be operable with one or more of the other at the same time or can be decoupled from each of the other two and be operable independent of the other two. In other examples, two or more, and perhaps all three of the drives can be mutually coupled relative to one another such that movements are substantially simultaneously imposed upon the patient's legs during use of the RKT apparatus.
The aforementioned sensors can be provided on the legs of a patient, in the power lines of the RKT apparatus, and/or on the X-, Y-, and Z-drives to obtain desired position or location data as the lower leg is moved during testing and evaluation. The degree of movement of the patient's legs in the A-P test, the V-V test, and/or the rotation test can be measured by detecting the movements of the parts of the apparatus, the rotation of the drives, and/or the actual movements of the patient's legs. The torque encountered during each test and over the range of motion applied during each such movement may also be measured, suitably calibrated to the limb movement, and recorded.
As noted above, even testing and evaluation of knee joints using the RKT apparatus 50 can be inconsistent from patient to patient, from doctor to doctor, and from test procedure to test procedure by the same doctors and/or on the same patients. Such inconsistency is created at least in part because each stage or step of the setup and testing procedure can introduce error into the data. The cumulative error can become quite substantial and thus significantly affect the accuracy of the test results. As disclosed herein, important stages or steps for each test are patient set-up and robot set-up. According to the teachings of the present disclosure, providing a consistent method or procedure to get a patient set-up in the RKT apparatus 50 has been determined to aid in producing more consistent test results and reducing error in the data. Further, according to the teachings of the present disclosure, providing a consistent method or procedure to set up or initialize the robot 54 of the RKT apparatus 50 prior to testing a given patient has also been determined to aid in producing more consistent test results and reducing error in the data.
As shown in
In the disclosed example, the X-, Y-, and Z-drives can be connected to and operable by the computer 202. The computer 202 can be programmed to receive and store load or torque data from the X-, Y-, and Z-drives 104, 106, 108 and to receive and store spatial position data from the sensors 210 and tracking system 208. The processor 206 can be programmed to calculate information and provide feedback related to knee laxity, based on the data. The information and feedback can be provided to the clinician on the display 205. The knee laxity information and feedback can relate to anterior-posterior movement, Varus-valgus movement, and/or tibia rotation movement, as described above. As represented in
With reference to
At block 302, the drives or motors of the robot 54 are leveled. In the disclosed example, to do so, the motors 110, 140, 160 of the corresponding X-, Y-, and Z-drives 104, 106, 108 can be precisely leveled relative to a horizontal or vertical reference or referencing a leveling device. In one example, a portion of the tracking system 208 can be used to precisely level the motors 110, 140, 160. Alternatively, the motors 110, 140, 160 can be leveled manually or mechanically such as by using an inclinometer. The objective of this step is to provide and define a consistent, repeatable starting point for the tibia positioning assembly 90 that can be achieved prior to each test using the RKT apparatus 50.
At block 304, the torque in each of the drives or motors is zeroed. In the disclosed example, to do so, each of the motors 110, 140, 160 of the drives 104, 106, 108 is zeroed. The motors 110, 140, 160 may thus be adjusted, positioned, or re-set to a condition where the torque transducers read zero torque or where the output shafts are under no torque. The objective of this step is to provide and define a consistent and repeatable starting condition, i.e., a neutral or zero torque starting point for each drive or motor prior to each test using the RKT apparatus 50.
At block 306, the patient is positioned or placed on or in the RKT apparatus 50 and relative to the robot 54. In the disclosed example, utilizing the positioning system 53, the robot can be moved relative to the table assembly 52 in order to provide easy ingress and egress for the patient. The patient is then situated in an orthostasis position between the robot 54 and table assembly 52. Using the step 57, the patient climbs onto the padded surface 60 of the patient platform 58 on the table assembly 52 and sits on the distal edge of the table assembly 52. The patient then lays back in a supine position with their trunk supported by the patient platform 58 and pulls their knees toward their chest. The robot 54 is then moved, via the positioning system 53, toward the table assembly 52. The patient may then extend their legs over the robot 54. The patient then positions their legs over the corresponding tibia positioning assemblies 90. First, the knee stabilizers 74 are manipulated to remove the upper knee clamping elements 78 so as to permit the legs of the patient to drop down onto the lower knee clamping elements 78 (see below at block 340 for more detail). The legs of the patient are then positioned so that the posterior joint line of each knee is directly over the front plane, i.e., the foot facing side of the corresponding knee stabilizer 74. The objective for this step is to provide a consistent, repeatable target position in the Z-axis direction for the knees of a patient with respect to the thigh immobilizers 70 and knee stabilizers 74. In this position, the lower legs of a patient are also free to bend at the knee forward of the lower knee clamping element 78 while the lower femur of each leg is fully supported on the pad 79 of the lower knee clamping element 78.
At block 308, the abduction angle of the patient's femurs is adjusted relative to their hips. In other words, the patient moves or is positioned on the table assembly 52 and on or in the tibia positioning assemblies 90 so that their femurs are at a desired abduction angle. In one example, the tibia positioning assemblies 90 may be pivotable or movable in order to adjust or change the angle between the two assemblies relative to a mid-line of the apparatus and/or the patient. This adjustment can be done in order to adjust the abduction angle of the patient's femurs so that their femurs are neutrally aligned with their hips in a fixed manner. Alternatively, and in this example, the tibia positioning assemblies 90 may be in a fixed abduction orientation, such as at a fixed 30-degree angle relative to one another, as noted above. The thigh immobilizers 70 may then be adjustable side-to-side, as further described below, so that the patient's femurs can be neutrally aligned with their hips. The objective of this step is to position the patient's femurs in a consistent, repeatable, and comfortable manner relative to the robot 54. The desired position is to have the femurs neutrally lined up with the patient's hips so as to limit stress on the patient's upper legs and hips during a test and to create a repeatable and consistent orientation of the lower legs relative to the femurs of the patient.
At block 309, the position of the robot 54 is adjusted relative to the patient's trunk and table assembly 52 in the horizontal and vertical directions to position the patient's knees in a desired degree of flexion. Using the column lift 63 of the positioning system 53, the robot 54 can be adjusted up or down to raise or lower the knees of the patient. The positioning system 53 may also be moved or rolled on the floor to retract or extend the legs of the patient. Utilizing the positioning system 53 can allow the clinician to position the patient's knees in the desired flexion in a range of 0 to 90 degrees. Once the desired knee flexion is reached, the robot 54 is fixed in position relative to the table assembly 52.
At block 310, the patient's knees are centered relative to the respective knee stabilizers 74. In the disclosed example, as shown in
In the disclosed example, to center the knee stabilizers 74 on the patient's knees, one can release the locking elements 316 and slide the knee stabilizers side-to-side along the respective slide track 314. The knee stabilizers 74 can be moved to center the corresponding posterior knee pads 79 on the lower knee clamping elements 78 under the knees of the patient. Though not specifically described herein, the locking elements 316 can include a corresponding knob 318 that is manipulated to lock or release the knee stabilizers 74 relative to the slide track 314. The construction of the support base, slide track 314, and locking elements 316 can vary considerably and still function as intended to provide side-to-side adjustability of the knee stabilizers 74. One objective of this step is to define a consistent and repeatable position for the patient's knees relative to the tibia positioning assemblies 90 generally in the X-axis direction. Another objective of this step is to center the patient's knees within the knee stabilizers 74 so that, when ultimately clamped onto the knees of the patient, each knee is centered among the pads 79 and thus securely retained in position to prevent movement of the femur and patella once clamped in the respective stabilizer.
At block 320, the thigh immobilizers 70 are adjusted to properly position and secure the patient's femurs in place. With reference to
A multi-function support 335 is fastened or otherwise attached to the top side at or near the middle of the mounting block 325. The support 335 may be rectangular, though much smaller than the mounting block 325, and includes a groove 339 formed in the upper surface of the support, the groove being oriented across the upper surface. The groove 339 is sized to fit a width of a guide bar 322 within the groove. The support 335 has mounting holes formed into the support within the groove 339 for fastening the guide bar 322 to the support 335. The guide bar 322 extends well beyond the parameters of the support 335 in both side-to-side directions and is spaced upward from the mounting block 325. The support 335 also has opposed end faces, each of which has a blind bore 347 formed therein. A fastener or stop pin 349 can be installed in each of the blind bores 347 for reasons discussed below. The support 335 can also be formed of any suitable material, take on different shapes, and be made using different processes, similar to the mounting block 325. Further, the mounting block 325 and support 335 can be two separate pieces joined to one another, as in this example, or can be formed as one integral part. In this example, as shown in
Each thigh immobilizer 70 has a pair of the femur clamping elements 72, i.e., a medial and a lateral clamping elements, that are spaced apart and width-wise adjustable relative to one another. Though not shown herein, the paddles 73 of the clamping elements 72 can include a pad or pads on the thigh facing surfaces, if desired, to provide a degree of comfort for a patient. The clamping elements 72, the trucks 324, and/or the paddles 73 can be replaced by other suitable securing or clamping devices or elements.
As shown in
Each actuator A1 and A2 includes a handle 328 and an actuator bar 329 extending from the respective handle. The actuator bar 329 on the actuator A1 is longer than and constructed slightly different than the bar on the actuator A2 for reasons noted below. Each actuator bar 329 is an elongated element with first apertures 336 for fastening the actuator to the truck 324. The first apertures 336 are oval or oblong slots. In the actuator A1, the first apertures 336 are positioned away from the handle 328 near the distal end of the longer actuator bar 322, which is configured to extend across the thigh immobilizer 70 and attach to the truck 324 of the inner or medial clamping element 72. In the actuator A2, the first apertures 336 are positioned near the handle 328 adjacent the proximal end of the shorter actuator bar 322, which is configured to attach to the truck 324 of the outer or lateral clamping element 72. Second apertures 343 in each of the actuator bars 322 are utilized to fasten and affix the actuator bars to the respective edge of the corresponding slide plates 330. The first apertures 336 are sufficiently long to allow for a degree of play or movement of the actuator bars 329 without moving the trucks 324. The actuator bars 329 are however rigidly fastened to the slide plates 330 through the second apertures 343.
Each actuator bar 329 also includes an elongate slot 338. The aforementioned pins 349 that protrude from the support 335 each protrude through a respective one of the slots 338. The slots 38 and pins 347 combine to limit the travel of the trucks 324 to which the actuator bars 329 are not attached.
The pins 33 may be cylindrical elements that are sized to fit within the cutout C of the locking plates 327. The springs 331 may include a spring portion 331a and an attachment portion 331b. The spring portions 331a may be made from a resilient, deformable material to allow for the spring portions to be compressed. The attachment portions 331b may be made from the same or different material than the spring portions 331a. The attachment portions 331b may be rectangular elements connected or integral to the spring portions 331a and can include through holes for securing the attachment portions 331b to the tops surfaces of the locking plates 327. The pins 333 are loosely captured between a contact end of the respective spring portions 331a and an edge of another leg of the locking plates 327.
As shown in
The assembled locking mechanisms 326 are depicted in
In use, each truck 324 and its corresponding locking mechanism 326 may slide independently inward toward the center of the thigh immobilizer 70 in order to bring the clamping elements 70 into contact with a patient's femur and thigh in a substantially fixed side-to-side position during testing, evaluation, or treatment. The independent movement of the trucks 324 allows for the ideal and/or equal pressure to be applied to the medial and lateral portions of the patient's thigh. As each truck 324 moves toward the thigh, the corresponding locking mechanism 326 prevents the truck 324 from reverse movement away from the thigh. This occurs by the clinician applying a force to the handles 328 of the actuators A1 and A2. In this example, the clinician can pull the actuator A1 in the outward direction and can push the actuator A2 inward towards the patient's thigh. In doing so, the actuator bars 329 act on the slide plates 330 to first move the slide plates 330 away from the respective pins 333 only slightly and without moving the truck 324 according to the length of the oval or oblong first apertures 336.
As the actuator A1 is pulled further away from the patient's thigh and the actuator A2 is pushed further toward the patient's thigh, the play in the first apertures 336 is eliminated. The ends of the first apertures 336 then act on the fasteners connected to the respective trucks 324, which in turn acts on the trucks 324 to move the trucks 324 and locking mechanism 326 toward the patient's thigh. As the locking mechanisms 326 slide toward the thigh, the pins 333 naturally push against the springs 331, compressing the spring portions 331a. The compression of the spring portions 331s allows for the pins 333 to move further into the cutouts C, which enables the pins 333 to slide along the guide bar 322. This movement allows the locking mechanisms 326 and trucks 324 to slide toward the patient's thigh. Once the clinician stops pulling on the actuator A1 and pushing on the actuator A2, the slide plates 330 will no longer force the pins 333 against the biasing force of the springs 331 into the cutouts C. The springs will then bias the pins 333 outward from the cutouts C. The pins 333 will then push against the slide plates 330, moving the actuator bars 329 and first apertures 336 in the opposite direction until the fasteners through the first apertures are borne against the other ends of the apertures. When this occurs, the pins 333 may be pinched between the guide bar 322 and the locking plates 327 and the guide bars will in turn be forced upward against the surfaces of the channels 341 under the trucks 324. This pressure within the channels 341 will thereby prevent movement of the trucks 324 in the opposite direction away from the thigh (see
To release the locking mechanism 326, a clinician applies a force to the handles 328 in the opposite directions from those noted above. In this example, the clinician would push on the actuator A1 and pull on the actuator A2 to release the locking mechanisms 326. The handles move the actuator bars 329, which in turn act on the respective slide plate 330. This causes the slide plates 330 to push the pins 333 back into the cutouts C and compress the springs 331. Pushing the pins 333 and compressing the springs 331 allows for the pins to move into the cutout C so that the pins 333 cease to forcibly engage the guide bar 322 and locking plates 327. Instead, clearance is created between the pins 333 and the guide bar 322 and locking plates 327. When sufficient clearance is obtained to release the locking mechanisms 326, the actuator bars 329 will continue to act on the slide plates 330, which in turn acts on the pins 330, which may in turn compress the springs 331, which moves the locking mechanisms 326 and the trucks 324 away from the patient's thigh.
As will be evident to those having ordinary skill in the art, the configuration and construction of the thigh immobilizer 70 can vary considerably from the example disclosed, illustrated, and described herein. The thigh immobilizer can be constructed from plastics (nylon), brass, aluminum, stainless steel or other materials that do not interfere with the electromagnetic system of the RKT apparatus. The thigh immobilizer 70 and the locking mechanism 326 can each be altered in configuration, size, shape, orientation, height, construction, materials, and the like. The thigh immobilizer 70 can include parts or elements that are assembled or connected to one another, as in the illustrated example. Alternatively, portions of the thigh immobilizer 70 can be formed as a unitary piece. The thigh immobilizer 70 can further include additional features, though not disclosed or described herein, that may be used to assist in securing a patient's thigh during testing of the knee and manipulation of the lower extremity or to otherwise enhance patient comfort or improve performance of the thigh immobilizer 70, the RKT apparatus, or both. Additionally, the thigh immobilizer can be used to secure other extremities of a patient, such as an arm, hand, ankle, etc. or any other portion of a patient that needs to be secured. A specific example and further details of the thigh immobilizer 70 described below.
Once the patient's knees are correctly positioned, according to the step at block 306, and the knee stabilizers 74 are centered according to the step at block 310, the thigh immobilizers 70 can be independently adjusted and set in a locked position against the medial and lateral portions of the patient's thighs. Each thigh immobilizer 70 can be slidably adjusted so that the respective thigh clamping elements 72 forcibly contact the sides of the patient's thigh. Each of the thigh clamping elements 72 should be positioned or secured such that the medial and lateral elements apply substantially equal pressure to the patient's thigh. One objective of this thigh clamping step is to permit a consistent and repeatable position for the patient's thighs relative to the tibia positioning assemblies 90, also generally in the X-axis direction. Another objective of this thigh clamping step is to then securely clamp the patient's thighs in place with thigh immobilizers 70. During testing, it is desirable that the femur position for each leg of a patient is securely retained to prevent side-to-side movement and femoral rotation once the thigh immobilizers 70 are adjusted and locked in place.
At block 340, each knee stabilizer 74 is clamped onto the patient's knee or patella. In the disclosed example, as depicted in
At this point, the locking elements 316 on the knee stabilizers 74 are still released so that the knee stabilizers 74 are free to slide or move along the slide track 314. Also at this point, the upper knee clamping element 78 should now be or should already have been reinstalled on the lower knee clamping element 78. The upper knee clamping element 78 is then clamped downward so that the pads 79 on the upper knee clamping element press down against the patella of the knee. The downward clamping force should achieve a predetermined or desired force, such as 30 lbs., and equal pressure should be applied to both the medial and lateral sides of each knee stabilizer 74. The knee stabilizers can then be secured in this clamping condition. In this example, the fixing screws can be rotated to secure the guide posts 342. A force gage or other suitable method and/or device can be used to achieve the desired downward clamping force applied by the knee stabilizers on each patella of the patient. Once the knee clamping elements 78 are clamped and locked, the knee stabilizers can then be locked in place on the slide track 314 by actuating the knobs 318. The objective of this knee clamping step is to securely clamp the patient's knee at the patella in with knee stabilizers 70. During testing, it is desirable that the lower end of the femur and the patella are securely retained to prevent vertical movement at the patella once the knee stabilizers 74 are adjusted, clamped down, and locked.
At block 350, the patient's feet are placed against the contact surfaces 94 and heel stops 93 of the foot plates 92. In the disclosed example, the tibia positioning assemblies are drawn toward the patient's feet by sliding the assembly along the tracks 80 on the sub-frames 68. In an alternative example, the drive system may be stationary and only the foot plates 92 may be adjustable along the Z-axis to contact the patient's feet. Once the feet are in contact with the two plates 92, the tibia positioning assemblies 90 are in a testing position relative to the patient's feet and lower legs. When the feet are properly positioned, appropriate straps (not shown) can be used to secure the feet to the foot plates. One objective of this step is to provide a consistent and repeatable mechanism to properly position the tibia positioning assemblies 90 along the sub-frames 68 relative to a specific patient. Another objective of this step is to secure the patient's feet to the foot plates and thus to the drive system of the tibia positioning assemblies.
At block 360, the tibia positioning assemblies 90 are locked in place. In the disclosed example, each tibia positioning assembly 90 can be locked in the position achieved at the step of block 350. For example, though not depicted herein, a lock/pin for each tibia positioning assembly 90 or on the sub-frame 68 can be inserted into a groove or hole on the other. This will lock the tibia positioning assemblies 90 at the adjusted position accommodating the particular patient being set up. A ruler 362 or other indicia or markings may be provided on or along one of the lengthwise parts of each sub-frame 68, such as along one of the rails 82 (see
At block 370, the patient's feet are rotated to a desired initial rotational orientation. In the disclosed example, each foot plate 92 can be manually rotated to a desired position determined by the orientation of a part of the patient's foot or a part of the foot plate. For example, the patient's foot could be positioned with the toes up and perpendicular to the floor beneath the RKT apparatus. More specifically, the starting orientation may be to orient the second toe on each foot point vertically perpendicular to the floor. This initial foot rotation position can instead be established by moving the Z-axis motor 160 into a neutral zero-torque position to find a true resting position for the patient's feet. The objective of this step is to define a consistent and repeatable starting orientation for the foot plates 92.
At block 380, each tibia rod device 96 is properly positioned under the patient's calves. In the disclosed example, each tibia rod device 96 can be length adjustable to retract or extend the calf plate 100 to a desired position under the corresponding calf of the patient. Once in the desired position, the calf plate is in a testing location or an AP test location relative to the patient's leg. A ruler or other indicia or markings (not shown) may be provided along part of the tibia rod device 96 to help determine the proper or desired position for the calf plate 100 (see
At block 390, tibial sensors 210 are placed on the patient's legs. In the disclosed example, sensors 210 are positioned on the flat region of the bone that is just medial to the tibia tubercle on each leg. The sensors 210 are then strapped into place at this location. The location is selected for the sensors 210 because this region has the least amount of soft tissue between the sensor and the bone. This location will thus help during testing to limit the degree of movement of the sensors caused by the soft tissue moving relative to bone. In one example, round sensor holders can be used to retain each sensor 210 in order to inhibit or prevent the sensors from rocking, due to compression of the calf muscle during testing.
Though not mentioned above, a ruler or other indicia or markings can be provided on other parts of the RKT apparatus to indicate specific positions of particular parts of the robot 54 after setting up a specific patient and the robot for testing. Rulers can also be provided on the thigh immobilizers 70, such as on the locking bar 322, and/or the knee stabilizers, such as on the slide track 314 and/or guide posts 342. In another example, a ruler can be provided on a portion of the tibia positioning assemblies 90, such as on the pivot plate 150, to indicate Varus-Valgus starting position. In yet another example, a marking scale may be provided on a portion of the Z-axis drive to indicate the position of the foot plates 92. Any such markings, indicia, or rulers can be used to record specific set-up parameters for a given patient that are repeatable from test to test each time the patient is set up for testing.
Additional set-up procedures may be utilized during testing or prior to testing in addition to those discussed above. For example, during AP testing, one or more straps may be utilized to secure the patients legs to the tibia rod devices 96. This may be to ensure that the tibia rod devices can both push up in an anterior direction on the patient's legs and pull down in a posterior direction on the patient's legs during testing. Once the AP test is completed, these straps may be removed and the tibia positioning rods can be moved out of the way prior to conducting a rotation test or a Varus-valgus test on the patient. In another example, during a Varus-valgus test, additional pads can be pushed into the knee stabilizers between the medial and lateral sides of the patient's knees and the framework 76. Such pads may help to minimize medial or lateral movement of the knee under the clamp and minimize axial rotation during the Varus-valgus test.
The patient and methods disclosed herein may vary from the examples shown and described. One or more of the specific steps may be performed as described but in a different order. Specific steps may be eliminated or altered and additional steps may be added. The design of the RKT apparatus may vary considerably from the example disclosed herein. As the design of the robot or apparatus varies, so may the steps vary, the order of the steps change, the number of steps change, and/or the specific details of the steps be altered or modified. The specific designs of the knee and thigh immobilizers may change, whether related to how the immobilizers are assembled, constructed, adjusted, locked, released, or the like. Likewise, the specific designs of the axis drives and/or the overall tibia positioning assemblies may also change.
The disclosed set-up procedures have been developed and are being refined in order to aid in reducing error and inconsistency in the test results and the underlying procedures. Some of the disclosed set-up steps are for setting up the patient position relative to the robot. Some of the disclosed set-up steps are for setting up the robot itself. However, all of the steps are conceived to aid in rendering the test procedures and results more accurate and more consistent. According to the disclosure, any patient can be set up relative to the robot in substantially the same way as any other patient. This can make knee laxity data acquired for different patients more directly comparable. According to the disclosure, a given patient can be set up relative to the robot in substantially the same way each time the patient is tested. This can make that patient's test results more relevant when comparing one test to the next. According to the disclosure, the robot can be set up using substantially the same procedure for any patient, other than where patient specific settings are known. This can reduce the amount of error that might otherwise be introduced into any given test.
Many modifications to and other embodiments of the disclosed RKT apparatus, components, methods, uses, and the like set forth herein may come to mind to one skilled in the art to which the invention pertains upon reading this disclosure. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments and combinations disclosed and that modifications and other embodiments and combinations are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
Specific combinations of features, components, aspects, procedures, methods, steps, processes, and arrangements of and for the disclosed RKT apparatus and set-up are disclosed herein. However, one having ordinary skill in the art will understand that each feature, component, aspect, procedure, method, step, process, and arrangement may be used independently or in other combinations not specifically disclosed.
Although certain RKT apparatuses and methods have been described herein in accordance with the teachings of the present disclosure, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all embodiments of the teachings of the disclosure that fairly fall within the scope of permissible equivalents.
