Source: https://patents.justia.com/patent/8361162
Timestamp: 2020-02-27 18:58:39
Document Index: 695958536

Matched Legal Cases: ['art 15', 'art 10', 'art 10', 'art 10', 'art 10', 'art 14', 'art 10', 'art 32', 'art 10', 'art 32', 'art 32', 'art 32', 'art 10', 'art 32', 'art 32', 'art 10', 'art 10', 'art 32', 'art 10', 'art 142']

US Patent for Orthopaedic joint prosthesis implant kit Patent (Patent # 8,361,162 issued January 29, 2013) - Justia Patents Search
Justia Patents Combined With Surgical ToolUS Patent for Orthopaedic joint prosthesis implant kit Patent (Patent # 8,361,162)
Aug 22, 2006 - DePuy International Limited
This invention relates to an orthopaedic joint prosthesis implant kit (2). The implant kit comprises a stem component (4) of an orthopaedic joint prosthesis which is intended for articulation with a mating component of the joint. The stem component has a distal end (6) and a proximal end (8), and a neck part (10) at the proximal end, and is configured for fixation in a bone cavity-using bone cement material with the distal end within the cavity and the proximal end at the opening of the cavity, and with the neck part protruding from the cavity towards the mating component of the joint. The implant kit further comprises a positioning kit (18), at least one spacer (20, 22, 24) for location between the wall of the cavity and the stem component at its proximal end, and a delivery device (26).
The present invention relates to an orthopaedic joint prosthesis implant kit and an implant positioning kit.
The preferred minimum thickness of cement can vary dependent on a number of factors such as the size of the bone and implant. However, typically, for a stem component for implantation into the femur of an adult, it can be important to ensure that the cement at any point around the stem component is not less than approximately 2 mm thick and preferably the thickness of the cement is in the range of approximately 2 mm to 5 mm.
Accordingly, in one aspect, the invention provides an orthopaedic joint prosthesis implant kit comprising:
a. a stem component of an orthopaedic joint prosthesis which is intended for articulation with a mating component of the joint, having a distal end and a proximal end, and a neck part at the proximal end, the stem component being configured for fixation in a bone cavity using bone cement material with the distal end within the cavity and the proximal end at the opening of the cavity, and with the neck part protruding from the cavity towards the mating component of the joint, and
b. a positioning kit for controlling the transverse position of the stem component within the cavity at the proximal end of the stem component, comprising:
i. at least one spacer for location between the wall of the cavity and the stem component at its proximal end to maintain a separation between the cavity wall and the stem component,
ii. a delivery device for locating the spacer between the cavity wall and the stem component at its head end, relative to the neck part of the stem component,
in which the delivery device can be separated from the spacer so that the spacer can be retained between the cavity wall and the implanted stem component after removal of the delivery device.
The spacer is an article which can fit between the stem component and the cavity wall at the proximal end of the stem component. The spacer can have an annular shape so that it extends around the periphery of the proximal end of the stem component. Preferably, the spacer does not fill the entire gap extending between the cavity wall and the stem component around the periphery of the stem component at its proximal end. This is advantageous as it allows the passage of bone cement past the spacer. Preferably, the spacer extends around not more than 50% of periphery of the stem component, more preferably not more than 25%, especially preferably not more than 10%, for example not more than 5%.
The spacer need not be shaped and sized so that it contacts both, or either of the cavity wall and the stem component. In many circumstances, the spacer will not actually contact both or either of the cavity wall or the stem component, as the separation between them is greater than the thickness of the spacer. In this case, the spacer is used to ensure that the separation between the stem component and the cavity wall does not reduce over time to less than the thickness of the spacer.
Preferably, the width of the spacer, in a direction taken between the cavity wall and the proximal end of the stem component when implanted, is not more than 10 mm, more preferably not more than 5 mm, especially preferably not more than 3 mm, for example not more than 2 mm.
Preferably, the frame can be slid over the neck part of the stem component, along the axis of the neck part, in order to position the spacer between the cavity wall and the stem component at its head end. This can ease the assembly of the positioning kit. As discussed above, it is the locking device that can control the position of the spacer relative to the neck part of the stem component. Therefore, being able to slide the frame over the neck part of the stem component enables the spacers to first be located approximately in the desired position between the cavity wall and the stem component at its head end before restricting relative movement between the spacers and the stem component by the locking device.
Preferably, each spacer extends around not more than 25% of periphery of the proximal end of the stem component, more preferably not more than 10%, especially preferably not more than 5%.
The spacer can be made from any material which is conventionally used in the manufacture of orthopaedic prostheses. Preferred materials include curable materials, especially acrylate polymers plastics. Particularly preferred materials include polymethylmethacrylate (PMMA) or a combination of PMMA and any plastic that will not adhere to PMMA. PMMA co-polymerised with styrene can also be used. Other polymers in the PMMA series can also be used such as PEMA, PBMA, etc.
According to a further aspect of the invention, there is provided a kit of parts for a positioning assembly for use with a stem component of an orthopaedic joint prosthesis. The kit of parts can include a collar adapted to engage about a neck of the stem component. At least one spacer separably connectable, or separably connected, to the collar can also be provided. When the spacer is attached to the collar, and with the collar engaged about the neck, the spacer can be positioned in a cavity to control the transverse separation between the stem component and the cavity.
FIG. 1 is a perspective view of an orthopaedic joint prosthesis implant kit according to a first embodiment of the present invention;
FIG. 2 is a perspective view of the implant kit shown in FIG. 1 after a first step of the procedure of using the implant kit to implant the stem component into a bone;
FIG. 3 is a perspective view of the implant kit shown in FIG. 1 after a second step of the procedure of implanting the stem component into a bone;
FIG. 4 is a perspective view of the stem component shown in FIG. 1 after a fourth step of implanting the stem component into a bone;
FIG. 5 is a perspective view of the implant kit and the bone into which the stem component is being implanted at the fourth step in the procedure for implanting the stem component;
FIG. 6 shows a perspective view of the implant kit and bone shown in FIG. 5 after a fifth step of the procedure of implanting the stem component in the bone;
FIG. 7 shows a front perspective view of a second embodiment of the invention;
FIG. 8 shows a rear perspective view of the second embodiment shown in FIG. 7; and
FIG. 9 shows an exploded perspective view of a delivery part and spacer parts of the embodiment shown in FIGS. 7 and 8.
Referring to the drawings, FIGS. 1 to 4 show the stem component 4 and the positioning kit 18 of the orthopaedic joint prosthesis kit 2. The stem component 4 is shown in FIGS. 5 and 6 implanted in the femur 16. The stem component 4 is shown in isolation from the femur 16 in FIGS. 1 to 4 for simplicity and ease of illustration. However, it will be appreciated that in practice, the stem component 4 shown in FIGS. 1 to 4 will be located in a pre-prepared cavity in the femur 16 during the implantation procedure.
The stem component 4 has a distal end 6 which is located in the femur in use and a proximal end 8, the majority of which extends from the resected surface of the femur. The proximal end 8 has a shoulder part 15 which extends into a neck part 10 which has a connector for attaching to a head component in the form of a generally tapering formation, referred to herein as the taper 13. In use, the neck part 10 and taper 13 protrudes from the cavity within the femur 16. The junction between the neck part 10 and taper 13 has a lip 12 extending around the periphery approximately a third of the way along the length of the exposed part of the stem component from the top end 14 of taper 13 to the shoulder portion 15. The top end 14 of the taper 13 is generally planar and is rounded in shape, particularly circular in shape, when viewed along the longitudinal axis of the neck part 10. The taper connector 13 between the lip 12 and its top end 14 tapers inwardly from the lip 12 to the top part 14. The taper 13 part of the neck part 10 provides a connector for receiving a head part (not shown) of the joint prosthesis which has a generally part-spherical shape and which can articulate in a mating pelvic component of the joint prosthesis.
The frame 28 comprises a generally annular planar body part 32 having four elongate generally straight side members. The side members are joined at their ends to form a looped configuration so that the body part can fit over the neck part 10 of the stem component 4 like a collar as shown in FIGS. 2 to 5. The frame 28 further comprises three legs 34, 36, 38 extending downwardly from the body part 32.
Each leg extends from the body part at the first ends of the legs, in a direction generally perpendicular to the plane of the body part 32. Each leg 34, 36, 38 carries at its second end distal to the body part, a spacer 20, 22, 24. Each leg 34, 36, 38 is spaced approximately equally around the body part 32. A first medial leg 34 supports spacer 20 at adjacent a medial part of the stem, a second anterior leg 36 supports spacer 22 adjacent an anterior part of the stem and a third posterior leg 38 supports spacer 24 adjacent a posterior part of the stem. This is the case for a left hand stem and for a right hand stem the anterior and posterior legs will swap. The legs locate the spacers around the should of the stem in the vicinity of the resection plane 60 of the femur as illustrated in FIG. 3.
The locking device 30 comprises a generally cylindrical body 48 wherein at least a part of its side wall is open between its ends so that the locking device 30 can be slid on to the taper 13 in a direction generally transverse to the longitudinal axis of the neck part as illustrated by arrow A in FIG. 2. The locking device 30 is open at both of its ends. However the proximal end of the delivery device which will be adjacent the proximal end of the taper 13 of the stem component 4 when in use, includes a ceiling 50 which extends part way across the open end of the generally cylindrical body 48.
In use, the frame 28 is slid over the neck part 10 along the access of the neck part like a collar in a direction indicated by arrow B until the frame cannot be slid along the axis any further as shown in FIG. 2. The spacers 20, 22, 24 will then be approximately in their desired position in the vicinity of the resection plane of the femur and located between the stem component 4 and the inner wall of the cavity in the femur 16.
The locking device 30 is then slid on to the taper 13 in a direction generally transverse to the axis of the neck part as illustrated by arrow A in FIG. 2. The locking device 30 is slid on to the taper 13 until the protrusions 46 extended into the hooks provided by the bar 40, the post 42 and the body part 32 of the frame 28. At this stage, the ceiling 50 of the locking device 30 abuts the planar top end 14 of the taper 13 and the ridge 52 engages the lip 12 of the taper 13. Accordingly, the ceiling 50 and the ridge 52 prevent movement of the locking device 30 in a direction parallel to the axis of the neck portion 10. Further, because the protrusions 46 of the delivery device 30 extend into the hooks provided by the body part 32 of the frame 28 and the bar 40, the frame 28 is prevented from moving in a direction parallel to the axis of the neck part 10.
Accordingly, the delivery device 30 controls the location of the spacers 20, 22 and 24. When assembled correctly, the spacers 20, 22, 24 will be located between the inner wall of the cavity in the bone 16 and the stem component at its proximal end in order to maintain a separation between the inner wall of the cavity and the outer surface of the stem component. The spacers 20,22, 24 are located so that their end proximal to the legs will be positioned at the resection plane 60 of the bone 16. The feet 52, 54 on the legs abut the resected surface of the femur and control the depth of insertion of the stem component into the cavity to prevent the stem component from being inserted too far into the femur.
The delivery device 26 is then removed from the stem component as illustrated in FIGS. 4 to 6. Firstly, the locking device 30 is slid off the taper 13 in a direction generally transverse to the axis of the neck part 10 in the direction illustrated by arrow C in FIG. 4. Once the locking device 30 is free from the hooks provided by the bar 40 and the body part 32 of the frame 28, the frame can be removed from the stem component by sliding it off the neck part 10 of the stem component in a direction generally parallel to the axis of the stem component as illustrated by arrow D in FIG. 6. The stiction forces between the spacers 20, 22, 24 and the bone cement ensures that the spacers detach from the delivery device and remain between the cavity wall and the stem component when the frame 28 is slid along the axis of the neck portion 10 to retain the stem in the correct position within the cavity.
FIGS. 7 to 9 show a further embodiment of the positioning kit 100 according to the present invention. Positioning kit 100 includes a two part delivery device 102 including a collar 104 and a locking device 106 and also three detachable spacers 108, 110, 112. Locking device 106, collar 104 and spacers 108, 110, 112 are similar to locking device 30, frame 28 and spacers 20, 22, 24 respectively. The substantial differences will be described below.
A front part of the collar includes a region of weakened mechanical strength, or a break or fracture line, 128 which allows the collar either to be opened up or split in half for removal as will be described in greater detail below. The weakened region 128 is provided by a V-shaped groove on the outer surface and a corresponding slit on the inner surface so that the thickness of material is reduce to provide a live hinge by which the collar can be pulled open. For example, the thickness of material can be approximately 0.3 mm between the groove and inner slit.
Toward the rear of the collar there are provided two grip formations each on a respective side of a narrow split in the collar. The grips are generally in the form of wings defining a generally concave structure for receiving a users thumbs to pull the collar open and apart. Above the grip formations 130, 132 are two respective projections 134, 136 which extend upwardly from an upper surface of the annular body 120 of the collar. Locking device 30 has an aperture in a lower part which has substantially the same width as the projections 134, 136. Hence, when assembled in use, as illustrated in FIG. 8, the projections are retained or captured in the aperture in the locking device to prevent the collar from opening. When the locking device has been removed, the collar can be easily removed by the user urging the collar apart with their thumbs on the grips 134, 136 so that the collar opens about the front groove. In different embodiments, the collar may simply break into two separate pieces by suitably configuring the materials properties.
The spacers 108, 110, and 112 differ to those described above in a number of ways. Each spacer 108, 110, 112 is identical and so only a single spacer needs to be manufactured. The top front edge 140 of each spacer is bevelled to allow the spacer to take up the correct angular position when attached to the medial position on the collar owing to the medial curvature of the stem. Three holes 144 are provided in the foot 126 to accept a press fit peg part 142 of the spacer. The peg part is off set to one side of the middle of the spacer body so that with suitably positioned holes 144, the same spacer can be used in any of the three positions, anterior, posterior or medial. As illustrated in FIG. 9, the medial hole is positioned to one side of the break line 128, and the anterior hole is located closer to the rear of the collar than the posterior hole (or vice versa depending on whether the collar is for a left or right stem). Hence, as the peg is off set, the same spacer can be used for each hole position.
1. An orthopaedic joint prosthesis implant kit comprising:
a stem component of an orthopaedic joint prosthesis intended for articulation with a mating component of the joint, having a distal end and a proximal end, and a neck part at the proximal end, the stem component being configured for fixation in a bone cavity using bone cement material with the distal end within the cavity and the proximal end at the opening of the cavity, and with the neck part protruding from the cavity towards the mating component of the joint; and
a positioning kit for controlling the transverse position of the stem component within the cavity at the proximal end of the component, comprising: i. at least two spacers for location between the wall of the cavity and the stem component at its proximal end to maintain a separation between the cavity wall and the stem component, wherein, when located between the stem component and the cavity wall, each of the spacers extends around not more than 10% of the periphery of the stem component; and ii. a delivery device attached to the at least two spacers for locating the spacers between the cavity wall and the proximal end of the stem component relative to the neck part of the stem component.
2. The implant kit of claim 1, wherein the delivery device is configured to be connected temporarily to the stem component to locate the at least two spacers relative to the neck part of the stem component.
3. The implant kit of claim 2, wherein the delivery device is configured to engage the neck part of the stem component to locate the at least two spacers relative to the neck part of the stem component.
4. The implant kit of claim 1, wherein the delivery device comprises a frame on which the at least two spacers are carried for delivery, and a locking device that engages the frame and the stem component to restrict relative movement therebetween.
5. The implant kit of claim 4, wherein the locking device engages the frame and the neck of the stem component to restrict relative movement therebetween.
6. The implant kit of claim 5, wherein the locking device slidably engages the neck in a direction generally transverse to the neck axis.
7. The implant kit of claim 5, wherein the frame and the locking device have inter-engaging formations by which relative movement therebetween is restricted.
8. The implant kit of claim 5, wherein the locking device and the neck of the stem component have inter-engaging formations by which relative movement therebetween is restricted.
9. The implant kit of claim 5, wherein the locking device restricts movement of the frame along the neck axis away from the mating component of the joint.
10. The implant kit of claim 5, wherein the locking device restricts movement of the frame along the neck axis towards the mating component of the joint.
11. The implant kit of claim 4, wherein the neck has a neck axis and the frame slidably engages the neck of the stem component along the neck axis.
12. The implant kit of claim 4, wherein the frame comprises a body that is slidable over the neck of the stem component, and at least one leg extending from the body part, wherein one of the at least two spacers is carried on the leg.
13. The implant kit of claim 12, wherein the end of the leg distal to the body part has a foot projecting from the leg, wherein the foot can rest on the surface of the bone to restrict movement of the body part relative to the bone cavity when the one of the at least two spacers is located relative to the neck part of the stem component.
14. The implant kit of claim 12, wherein the leg and the one of the at least two spacers are provided as one piece with a line of weakness therebetween that can be broken to allow the leg and said spacer to be separated.
15. The implant kit of claim 12, wherein the leg and said spacer are provided as separate pieces that are detachably attached to one another.
16. The implant kit of claim 15, wherein the leg and said spacer are fastened to one another by a friction fit.
17. The implant kit of claim 1, wherein said spacer tapers towards a point at its end distal to the delivery device.
18. A kit of parts for a positioning assembly for use with a stem component of an orthopaedic joint prosthesis having a distal end and a proximal end, and a neck at the proximal end, the stem component being configured for fixation in a bone cavity using bone cement material with the distal end within the cavity and the proximal end at the opening of the cavity, and with the neck protruding from the cavity, the kit of parts comprising:
a delivery device including a collar adapted to engage about the neck; and
at least two spacers separably connectable or separably connected to the collar, wherein when the spacers are attached to the collar, and with the collar engaged about the neck, the spacers are positioned in the cavity to control the separation between the stem component and the cavity, and wherein, when located between the stem component and the cavity wall, each of the spacers extends around not more than 10% of the periphery of the stem component.
19. The kit of claim 18, wherein the stem has a longitudinal axis and the delivery device includes a hinge by which the delivery device can be at least partially opened to allow the delivery device to be removed at least partially transversely to the longitudinal axis.
20. The kit of claim 19, wherein the delivery device includes grips by which a user can open the delivery device using their digits.
Patent Publication Number: 20100298943
Inventors: Daniel Berry (Rochester, MN), Andrew Donn (Vancouver), Brian Griffiths (Hants), Fiona Haig (Cambridge), Graham Isaac (Huddersfield), Thomas Schmalzried (Rolling Hills, CA)
Application Number: 12/065,580
Current U.S. Class: Combined With Surgical Tool (623/22.12); Including Sleeve Around Stem Member (623/23.46); Having A Collar (623/23.21)
International Classification: A61F 2/32 (20060101); A61F 2/36 (20060101); A61F 2/30 (20060101);