Patent Application
20140243825
Orthopedic devices for treating arthritic joints or repairing bone defects and, more specifically, to orthopedic device assemblies for providing fusion, fixation, compression, and/or stabilization of the ankle (tibiotalar) and subtalar (talocalcaneal) joints.
Orthopedic devices, such as nails, rods, or pins, are often used in the medical field for fusing bones or bone segments across a joint to correct deformities, treat arthritis, or remedy other issues with procedures such as with a tibiotalocalcaneal arthrodesis. Such orthopedic devices may also be used to treat fractures of long bones, such as in the humerus, radius, ulna, tibia, fibula, femur, metacarpal, and metatarsal, or other non-long bones, such as the calanceus and other tarsal or carpal bones. Such devices are typically designed to be inserted across a joint or fracture site into the bone on either side of the joint or fracture, and generally are fastened to the bones on either side of a joint or to bone segments on either side of the fracture to stabilize the bone and promote proper fusion or healing.
In some cases, the bones or bone segments on either side of a joint or fracture are spaced apart and must be brought closer together to promote fusion or healing. Devices have been proposed that provide compression between bones or bone segments by fixing the orthopedic device to one bone (or bone segment) and then moving the second bone towards the bone in which the device is fixed by way of an external device which applies compression to the end of the second bone. The second bone is then secured to the orthopedic device and the joint is allowed to fuse or the fracture is allowed to heal. However, these compression providing devices must be securely and removably attached to the orthopedic device while not compromising the integrity of the orthopedic device or the ability of the compression device to provide appropriate compression. Further, existing compression mechanisms may apply compression across weak bones or by pressing on the surface of a patient's skin, both of which may result in negative complications. In some cases, a drill guide must also be securely and removably attached to the orthopedic device.
Thus, there remains a need for an orthopedic device assembly that is easy to install without the need for extensive surgical dissection, and provides appropriate compression of the bone to promote fusion or healing.
Example embodiments of the present invention generally related to an orthopedic device for providing compression across a joint, fracture, or defect of a bone. One example embodiment of an orthopedic device may include a core with at least one opening configured to receive a fastener for securing the core to a first bone portion, and at least one ratchet or pawl member. The orthopedic device may further include a sleeve including at least one open end for slidably receiving the core, at least one opening configured to receive a fastener for fastening the sleeve to a second bone portion, and at least one ratchet or pawl member disposed at least partially within the sleeve and configured to engage the ratchet or pawl member of the core. The engaged ratchet and pawl member may cooperate to allow the core to move into the sleeve in a direction through the open end and preclude the core from moving out of the sleeve in the opposite direction.
The pawl member may include at least one pawl surface that is biased against a ratchet surface of the ratchet. The core may include a slot where the slot is configured to receive at least a portion of the pawl member. The sleeve may include an inner bore into which the core is received where the inner bore includes the ratchet surface. The orthopedic device may further include an end cap configured to limit the distance the core can advance into the sleeve. The orthopedic device may further include at least one fastener insert disposed within the at least one opening of the sleeve, where the at least one fastener insert is configured to engage the fastener received through the at least one opening of the sleeve. The core may include at least one slot where the at least one fastener insert may be configured to pass through the at least one slot of the core and the at least one fastener insert may be configured to preclude relative rotation between the core and the sleeve.
Another example of an orthopedic device assembly according to embodiments of the present invention may include an orthopedic device including a core and a sleeve. The assembly may further include a target guide and a compression assembly configured to attach the orthopedic device to the target guide, where the compression assembly may be configured to draw the core into the sleeve. The orthopedic device may further include a pawl member disposed between the core and the sleeve where the pawl member is configured to allow the core to be drawn into the sleeve and preclude the core from sliding out of the sleeve. The compression assembly may include a core attachment bolt configured to engage the core and draw the core into the sleeve in response to the core attachment bolt turning with respect to the core. The orthopedic device may include at least one hole disposed in the core configured to receive a fastener and at least one hole disposed in the sleeve configured to receive a fastener. The fastener received in the at least one hole disposed in the core may be configured to attach the core to a distal bone portion and a fastener received in the at least one hole disposed in the sleeve may be configured to attach the sleeve to a proximal bone portion. The at least one hole disposed in the sleeve may be configured to receive at least one fastener insert, where the fastener received through the at least one hole in the sleeve engages the at least one fastener insert. The core may further include at least one slot where the at least one fastener insert may be configured to pass through the at least one slot of the core and preclude relative motion between the sleeve and the core. Compression may be applied between the distal bone portion and the proximal bone portion in response to the compression assembly drawing the core into the sleeve.
Example embodiments of the present invention may provide a method of applying compression between a distal bone portion and a proximal bone portion using an orthopedic device. The method may include inserting the orthopedic device through the proximal bone portion and into the distal bone portion, where the orthopedic device includes a core and a sleeve. The method may further include fastening the core to the distal bone portion and fastening the sleeve to the proximal bone portion. The method may further include applying initial compression between the distal bone portion and the proximal bone portion. The method may further include maintaining compression between the distal bone portion and the proximal bone portion with a pawl member. The method may also include allowing for dynamic compression between the distal bone portion and the proximal bone portion after the initial compression has been achieved and maintaining the dynamic compression between the distal bone portion and the proximal bone portion with the pawl member. The method may still further include limiting the dynamic compression between the distal bone portion and the proximal bone portion. Applying initial compression between the distal bone portion and the proximal bone portion may include drawing the core into the sleeve. Drawing the core into the sleeve may include using a compression assembly to draw the core into the sleeve. Using a compression assembly to draw the core into the sleeve may include engaging a threaded bore of the core with a threaded stud and rotating the threaded stud relative to the core. The core may be held in rotational alignment with the sleeve.
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
Embodiments of the present invention generally relate to an orthopedic device assembly for fusing bones, bone segments, or bone portions in order to fuse joints, repair fractures, repair bone defects, or otherwise add rigidity to a bone or bone portions. For ease of explanation, however, the specification and accompanying figures will refer to fusion of a joint, and in particular, the ankle (tibiotalar) or subtalar (talocalcaneal) joint, although it is to be understood that any type of bone repair or fusion, including the repair of fractures, osteotomies, and other bone defects or fusion sites, and combinations thereof, may be accomplished using embodiments of the device described herein. Further, while example embodiments of the present invention are illustrated as fusing two bones together, example embodiments may be used to join two or more different bones together for fusion, join two or more bone segments together to heal across a fracture, or otherwise strengthen a single or multiple bones. As such, the term “bone portion” is used herein to describe any portion of a bone up to and including an entire bone such that fusion of a first bone portion with a second bone portion may describe two separate bones or two portions of a single bone. Further, while example embodiments of the present device describe the fusion of two bone portions or bone segments, example embodiments may further apply compression between more than two bone segments, such as, for example, applying compression between the tibia, talus, and calcaneus bones. Compression applied and maintained by example embodiments of the present invention may be applied across any number of bones or bone segments wherein the compression is applied coaxially across the bones or bone segments. The illustrated example embodiments in which compression is applied across two bones is provided for illustration and is not intended to be limiting.
As described further below, the orthopedic device assembly includes an orthopedic device that may be configured to be inserted through the calcaneus bone of the foot, through the talus, and into the tibia. An orthopedic device according to the present invention may be inserted through the calcaneus bone of the foot, through the talus, and into the core of the tibia bone such that the orthopedic device is disposed at least partially within the tibia, partially within the talus, and partially within the calcaneus. The orthopedic device assembly may include a compression assembly that may be configured to facilitate compression between the calcaneus and the talus, and the talus and the tibia. By fastening the installed orthopedic device to the tibia on a distal side of the joint and to the calcaneus on the proximal side of the joint and subsequently compressing the orthopedic device, the calcaneus bone and the tibia may be drawn towards one another such that compression is applied across the joint to facilitate fusion. The orthopedic device may further be installed through the talus bone disposed between the tibia and calcaneus wherein the talus bone may be secured to the orthopedic device or the talus may be secured by compression applied on either side of the talus between the tibia and calcaneus bones. Once the orthopedic device is installed, the patient may or may not be able to use the affected appendage during the fusion process. In other example embodiments wherein the orthopedic device is configured for the repair of a fracture, the fracture may be entirely across the bone creating two separate bone portions or may only extend partially across the bone creating two partially separate bone portions. The orthopedic device may be inserted along the axis of the fractured bone, such as along the intramedullary canal of a long bone, and extend across the fracture. The orthopedic device may provide compression between the two bone portions across the fracture to facilitate healing of the fracture.
In this regard, the terms “proximal” and “distal” refer to locations relative to the insertion site of the assembly after it has been inserted into the bone rather than anatomical convention. In other words according to example embodiments provided herein, the proximal bone may refer to the calcaneus bone where the orthopedic device is inserted while the distal bone may refer to the tibia that receives a distal portion of the orthopedic device assembly.
The orthopedic device 100 may be used in conjunction with a target guide to perform an arthrodesis, as described below. The orthopedic device 100 may be configured (i.e., shaped and sized) to be inserted into a bone and fastened to the bone on either side of the joint. Thus, the particular configuration of the orthopedic device 100 may vary depending on the type and size of the bone and joint to be treated. Furthermore, the device may be made of any absorbable or non-absorbable material that is compatible for use inside the human body, such as titanium, stainless steel, cobalt chrome, plastic, carbon fiber, or polymer. The core 110 and sleeve 120 may, for example, be made of a rigid material such as titanium alloy which may provide the necessary strength and rigidity while being substantially non-reactive with the human body.
In the embodiment illustrated in
The orthopedic device 100 may include a number of holes 130, 140 configured to receive fasteners for fastening bones, or portions thereof, to the orthopedic device 100. One or more of the holes 130 may be located towards the distal end of the orthopedic device 100, for example to fasten a bone, such as a tibia that is on a distal side of the joint, to the orthopedic device 100, whereas one or more other holes 140 may be located towards the proximal end of the orthopedic device 100, for fastening another bone portion, such as the calcaneus, that is on a proximal side of the joint, as discussed below. Furthermore, the holes 130, 140 may be configured to receive various types of fasteners, such as pins, bolts, pegs, screws, and locking screws, among others. In some cases, the holes 130, 140 may be internally-threaded to receive corresponding externally threaded fasteners. The holes 130, 140 may have a chamfered opening on the side configured to receive a corresponding fastener which may aid insertion of the fastener by providing a larger opening to accept and guide the fastener.
Any number of ratcheting mechanisms may be employed beyond what is illustrated in the figures as will be apparent to one of ordinary skill in the art. However, one particular advantage to the illustrated pawl member 160 is that the ratchet surfaces are not outwardly exposed when the core 110 and sleeve 120 are assembled. Enclosing the pawl and ratchet surfaces within the orthopedic device 100 may be advantageous because the ratchet surfaces will not become obstructed with tissue or bone and the orthopedic device maintains a relatively smooth external surface which aids installation and is better for maintaining sterility. When the core 110 is assembled with the sleeve 120, a pin 170 may be configured to be inserted through hole 174 of the sleeve 120 and through hole 172 of the core 110 to prevent relative motion between the core 110 and the sleeve 120 until the pin 170 is removed prior to the installation of the orthopedic device 100 into a bone. The term “pawl member” is used herein to describe the component engaging the ratchet surface 125 disposed on the inside bore of the sleeve 120 and may describe any member that engages the ratchet surface 125 to allow movement in a first direction and preclude movement in a second, opposite direction. While the depicted embodiment illustrates the pawl member 160 disposed within or proximate the core 110 and the ratchet surface 125 disposed within the sleeve 120, optionally, the ratchet surface may be disposed on the core 110 with a pawl member disposed within the sleeve 120.
The sleeve 120 further comprises fastener inserts 145, which are secured within the holes 140. The fastener inserts 145 may include a threaded bore for receiving a fastener when installed in a bone or they may have a smooth bore through which a fastener may be inserted during attachment to the bone. In the instance of a threaded bore fastener insert 145, the threads may include a locking feature such as a locking-profile thread, a deformable locking member (e.g. an elastic stop nut or elliptical offset locknut type thread) or possibly an adhesive.
The nail is assembled with the pawl member 160 inserted into slot 150 of the core 110. The core 110 is then inserted into the sleeve 120 until hole 172 of the core is aligned with hole 174 of the sleeve at which point the pin 170 may be installed to prevent relative motion between the core 110 and the sleeve 120. The fastener inserts 145 may then be aligned and inserted into holes 140. The fastener inserts 145 may be received through slots 180 of the core 110. The fastener inserts 145 may then be securely attached (e.g. with welding, adhesive, etc.) within the holes 140. The slots 180 permit the core 110 to slide within the sleeve 120 and the fastener inserts 145 both preclude entry of foreign substances (tissue, bone, etc.) into the bore of the sleeve 120 and provide a bore configured to receive a fastener to secure the sleeve 120 to the bone of a patient. The slots 180 further allow the proximal end 112 of the core 110 to be accessible through the proximal end 122 of the sleeve 120 as will be described further below. In addition, the fastener inserts 145 which pass through the slots 180 in the core 110 preclude relative rotation between the core 110 and the sleeve 120. Precluding relative rotation between the core 110 and the sleeve 120 maintains the relative alignment between the bores of the fastener inserts 145 and the fastener holes 130 of the core 110 which may be required to facilitate the drilling of holes and insertion of fasteners as will be described further below.
As illustrated in
The compression assembly 500 includes a compressor sleeve 510 which is held fixed to the top 330 through hole 335. A sleeve attachment bolt includes a top portion 570 at the proximal end of the compression assembly 500 and a shaft 560 that extends through the compressor sleeve 510 and exits the compressor sleeve 510 at the distal end. The shaft includes an externally threaded end 560 which extends beyond the compressor sleeve 510. The externally threaded end 560 may engage an internally threaded proximal end of the sleeve 120 to attach the sleeve 120 to the compressor sleeve 510. The compressor sleeve 510 may further include pins 550 that extend from the distal end of the compressor sleeve 510. The pins 550 may engage corresponding alignment recesses 121 in the proximal end of the sleeve 120 as shown in
The compression assembly 500 further includes a core attachment bolt 520 that extends through the compressor sleeve 510 and through the sleeve attachment bolt 560, 570. The core attachment bolt is free to rotate within the sleeve attachment bolt 560, 570 independent of the compressor sleeve 510 or the sleeve attachment bolt 560, 570. The core attachment bolt 520 may include a head 525 and a handle, such as turnstile handle 530. The turnstile handle 530 includes spokes 540 configured to permit a user to apply a rotational force to the core attachment bolt 520. The core attachment bolt head 525 may include a hexagonal external shape, an Allen-keyway or Torx® keyway to enable a user to apply torque or for application of a torque wrench or torque-limiting driver to the core attachment bolt 520. The distal end of the core attachment bolt 520 may include an externally threaded portion configured to engage the proximal end of the core 110.
Optionally, the target guide 300 may be configured to receive or engage a leverage bridge 950 as illustrated in
In practice, with an orthopedic device inserted into the bone of a patient and the target guide attached thereto, the drill guide 630 may be inserted into the screw guide 620, and the two may together be inserted through an alignment hole 610 of the target guide 300, through an incision in the skin of the patient, through the flesh, and into contact with the bone. A drill bit attached to a drill may be inserted through the bore of the drill guide 630 to drill a hole through the bone. The drill guide 630 properly locates the position of the drill bit such that a hole created by the drill bit penetrates the bone in alignment with a fastener hole 130, 140 of the orthopedic device. Once the hole has been drilled, the drill guide 630 may be removed from the screw guide 620. As the drill guide 630 occupied the bore of the screw guide 620, the bore of the screw guide 620 may then be substantially free of tissue, bone, or other substances such that a surgeon may insert a screw or other fastener into the bore of the screw guide 620. The screw guide 620 guides the fastener into alignment with a fastener hole 130, 140 of the orthopedic device. A tool, such as a screw driver, Torx® driver, or other tool may then be used to fasten the fastener through the hole drilled in the bone, across the fastener hole 130, 140 of the orthopedic device, and into the bone on the opposite side from the screw guide 620. Once the fastener is inserted and properly tightened, the screw guide 620 may be removed from the alignment hole 610 and the patient.
As outlined above, example embodiments of the present invention may provide a method for fusing together bone portions on either side of a joint. Initially, an assembly comprising an orthopedic device 100, a compression assembly 500, and a target guide 300 appropriate for the bone containing the defect may be selected. In the case of an ankle arthrodesis, a hole may be drilled through the calcaneus bone to receive the orthopedic device 100. The bone which is to receive the orthopedic device, such as the tibia, may, in some cases, be prepared beforehand for receiving the orthopedic device 100 using tools and methods known by those skilled in the art, such as by drilling and/or reaming the bone so that the dimensions of the channel formed in the bone correspond to the dimensions of the orthopedic device 100. The orthopedic device may then be inserted through the calcaneus and into the prepared channel of the tibia. For example, referring to
The calcaneus 701 and tibia 700 and appendage profile of the flesh 710 are shown for illustrative purposes only. Between the calcaneus bone 701 and the tibia 700 is the ankle joint 720. The orthopedic device 100 extends from the calcaneus bone 701, across the joint 720, into the tibia bone 700. As illustrated, the drill guide 630 and screw guide 620 are engaged with the calcaneus bone 701 in position to facilitate a drilling operation as described above. Fastener 750 is illustrated in the installed position wherein the fastener 750 couples together the orthopedic device core 110 and the tibia 700. Additional fasteners may be used depending upon the size of the bone, the fastener size, and the strength of the fastener-bone interface (e.g., a weak bone may require more fasteners to distribute the forces within the bone). Fasteners are also installed through the calcaneus bone 701 and through the sleeve 120 of the orthopedic device 100.
Once the orthopedic device 100 is secured within the bone (i.e., the core 110 is secured to the tibia 700 and the sleeve 120 is secured to the calcaneus bone 701), the screw guide(s) are removed from the target guide 300. The turnstile handle 530 may be turned to draw the core 110 into the sleeve 120, thereby shortening the overall length of the orthopedic device and applying compression across the joint 720. As the turnstile handle 530 is turned, the core attachment bolt 520 draws the core 110 into the sleeve 120. As the core 110 is drawn into the sleeve 120, the pawl member 160 and ratchet surface 125 cooperate to allow movement of the core 110 in the proximal direction into the sleeve 120, but preclude movement of the core 110 in the distal direction, out of the sleeve 120. Thus, as the core 110 advances into the sleeve 120 compression across the joint 720 is achieved and maintained. The length in which the core 110 can be drawn into the sleeve 120 may be configured according to the size and application of the orthopedic device, and may be up to around 15 millimeters for an application such as a tibiotalocalcaneal arthrodesis.
In any case, the target guide 300 and compression assembly 500 may not be needed once the desired amount of compression has been achieved and the orthopedic device 100 compressed to the desired force or distance. As a result, the compression assembly 500 may be disconnected from the orthopedic device by disengagement of the core attachment bolt 520 from the core 110 and the sleeve attachment bolt 560 may be disengaged from the sleeve 120. The attachment straps 350 of the target guide 300 may then be removed from the patient and the target guide 300, together with the compression assembly 500 may be removed. In this way, the orthopedic device 100 may remain in the bone, with the calcaneus 701 and tibia 700 attached to facilitate stabilization of the joint and promote proper fusion and to provide a relatively unobstructed surface of the bone and allow the patient to use the affected part to the extent possible with greater comfort. The orthopedic device 100 may provide compression across both the ankle and subtalar joints in applications such as with a tibiotalocalcaneal arthrodesis.
The proximal end of the orthopedic device 101 is preferably situated such that it does not protrude from the cortex of the calcaneus bone 701 as a protrusion from beneath the heel of a patient could be both uncomfortable and detrimental to the fusion of the joint. The radiolucent target guide 300 may include a groove 303, such as a v-shaped groove, extending at least partially across the side pylons 320 and/or the posterior pylon (not shown in
Referring now to
Advantageously, the orthopedic device 100 may be configured for dynamic compression, wherein after the orthopedic device has been inserted, compressed, and the surgery is complete, the orthopedic device may further compress (by virtue of the core 110 sliding further into the sleeve 120 and the compression being held by the ratchet mechanism) during normal activity of the patient. Since the pawl member and ratchet surface cooperate to preclude movement of the core 110 out of the sleeve 120, as the orthopedic device 100 compresses, the orthopedic device 100 remains in its most compressed length. Such dynamic compression may be desirable to achieve better compression across the joint 720 as the bone portions 700, 701 fuse across the joint.
The amount of dynamic compression may be limited by insertion of the appropriate end cap 800. For example, after initial compression during the surgery and subsequent removal of the compression assembly, an end cap 800 may be installed in the proximal end 101 of the orthopedic device 100 such that the distal end 801 of the end cap 800 does not contact the proximal end of the core 110. The space between the distal end 801 of an inserted end cap 800 and the proximal end of the core 110 limits the maximum dynamic compression of the distance between the core 110 and the end cap 800. This maximum allowable dynamic compression may be varied based upon the selection of end caps 800 of different lengths. A longer end cap 800 will permit less (possibly zero) dynamic compression while a shorter end cap 800 will allow greater dynamic compression in the same patient. For example, for a patient in which the bone quality is poor (e.g., the bone is brittle or otherwise weakened), the maximum dynamic compression may be reduced such that the bone interface that is to be fused is not damaged by further fracture. Additionally, the threads used to engage the end cap 800 may also be used to facilitate removal of the orthopedic device from the patient by means of attaching a handle or other device to the threads (not shown).
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments 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.
This application claims priority to U.S. patent application Ser. No. 13/029,897 filed on Feb. 17, 2011, and published as U.S. Patent Application Publication No. 2012/0215222, and is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13029897 | Feb 2011 | US |
| Child | 14168610 | US |
