Hinge Knee Assembly Guide

Abstract

A total knee prosthesis system that includes a guide having first and second wedges each having a thickness configured to be located between the tibial and femoral component. When the first and second wedges are located between the tibial and femoral component, the first and second wedges align the first axle opening of the tibial component with the second axle opening of the femoral component for receipt of an axle. The guide includes a guide recess extending between the first and second wedges and a post extending into the guide recess. The guide also includes a bridge connected to and extending between the first and second wedges such that the bridge at least partially defines the guide recess.

Claims

1. A method of assembling a hinge knee prosthesis, comprising: coupling an alignment member with a tibial component having a first axle opening; positioning a head portion of a coupling component extending from the tibial component into an intercondylar recess of a femoral component having a second axle opening; engaging the femoral component with the alignment member such that the first axle opening aligns with the second axle opening; inserting an axle into the first and second axle openings so as to hingedly connect the femoral component with the coupling component; and after inserting the axle, removing the alignment member from the tibial component.

2. The method of claim 1, wherein engaging the femoral component with the alignment member includes seating at least one condylar surface of the femoral component on a corresponding curved proximal surface of the alignment member.

3. The method of claim 2, wherein when engaging the femoral component on the alignment member, the curved proximal surface of the alignment member supports the femoral component and a thickness thereof aligns the first and second axle openings.

4. The method of claim 1, further comprising connecting an insert to a baseplate of the tibial component.

5. The method of claim 4, further comprising inserting a bearing of the coupling component into an opening of the baseplate.

6. The method of claim 4, wherein connecting the insert to the baseplate of the tibial component occurs prior to inserting the alignment member into the tibial component.

7. The method of claim 1, wherein coupling the alignment member with the tibial component includes inserting a post of the alignment member into a post opening of the head portion.

8. The method of claim 1, wherein the alignment member has first and second wedges each having a thickness configured to be located between the tibial component and the femoral component.

9. The method of claim 8, wherein when the first and second wedges are located between the tibial component and the femoral component after seating the femoral component on the alignment member, the first and second wedges align the first axle opening with the second axle opening.

10. The method of claim 1, wherein the alignment member is a wedge-shaped alignment member having a thickness such that, when engaging the femoral component with the wedge-shaped alignment member, the thickness of the wedge-shaped alignment member aligns the first axle opening with the second axle opening.

11. The method of claim 1, further comprising connecting the tibial component to a resected proximal tibia.

12. The method of claim 11, wherein the tibial component includes the coupling component and a baseplate component.

13. The method of claim 12, wherein connecting the tibial component to the resected proximal tibia further comprises: connecting the baseplate component to the resected proximal tibia; inserting a bearing bushing into an opening of the baseplate component; connecting an insert to the baseplate component; and inserting a bearing of the coupling component into the opening of the baseplate component and the bearing bushing.

14. The method of claim 1, further comprising connecting the femoral component to a resected distal femur.

15. The method of claim 14, further comprising inserting one or more axle bushing into respective transverse openings of the femoral component.

16. A method of assembling a hinge knee prosthesis, comprising: positioning an alignment member between a tibial component and a femoral component, wherein the alignment member is configured to position the femoral component relative to a head portion of a coupling component extending from the tibial component such that a first axle opening of the femoral component aligns with a second axle opening of the coupling component; positioning the head portion of the coupling component into an intercondylar recess of the femoral component; inserting an axle into the first and second axle openings so as to hingedly connect the femoral component with the coupling component; and after inserting the axle, removing the alignment member from between the tibial component and the femoral component.

17. The method of claim 16, wherein positioning the alignment member includes wedging the alignment member between the tibial component and femoral component so that an upper surface of the alignment member supports the femoral component and a thickness thereof aligns the first and second axle openings.

18. The method of claim 16, further comprising: connecting a polymer insert to a baseplate of the tibial component, the polymer insert having a concave proximal surface; and inserting a bearing of the coupling component into an opening in the baseplate.

19. The method of claim 18, wherein connecting the polymer insert to the baseplate is performed prior to positioning the alignment member between the tibial component and femoral component.

20. The method of claim 16, wherein positioning the alignment member between the tibial component and femoral component includes: inserting a post of the alignment member into a post opening of the head portion; and contacting at least one condylar portion of the femoral component with a respective alignment portion of the alignment member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The features, aspects, and advantages of the present disclosure will become better understood with regard to the following description, appended claims, and accompanying drawings in which:

[0014] FIG. 1 is an exploded view of a total knee prosthesis system including an assembly guide.

[0015] FIG. 2A is a perspective view of the assembly guide of FIG. 1 according to one embodiment of the present invention.

[0016] FIG. 2B is a side elevational view of the assembly guide of FIG. 2A.

[0017] FIG. 2C is a top view of the assembly guide of FIG. 2A.

[0018] FIG. 3A is a side view of a partial assembly of the total knee prosthesis system.

[0019] FIG. 3B is a perspective view of the partial assembly of FIG. 3A.

DETAILED DESCRIPTION

[0020] When referring to specific directions in the following discussion of certain implantable devices, it should be understood that such directions are described with regard to the implantable device's orientation and position during exemplary application to the human body. Thus, as used herein, the term “proximal” means close to the heart, and the term “distal” means more distant from the heart. The term “inferior” means toward the feet, and the term “superior” means toward the head. The term “anterior means toward the front of the body or the face, and the term “posterior” means toward the back of the body. The term “medial” means toward the midline of the body, and the term “lateral” means away from the midline of the body. Also, as used herein, the terms “about,” “generally” and “substantially” are intended to mean that deviations from absolute are included within the scope of the term so modified.

[0021] FIG. 1 depicts a hinge knee prosthesis system 100 according to one embodiment of the present invention. System 100 includes a tibial component or tibial assembly, axle 160, axle bushings 170, a femoral component 180, bumper 150, and alignment wedge 20. The tibial component, according to the depicted embodiment, generally includes a baseplate component 110, bearing bushing 120, tibial insert 130, and bearing component 140.

[0022] The baseplate component 110 may be comprised of various components that are separate components or integrally formed. In the depicted embodiment, baseplate component 110 includes a baseplate portion 112, stem 114, and keel 116. Baseplate portion 112 includes a proximal surface 111 that is configured to receive and retain tibial insert 130. Baseplate portion 112 also includes a distal or bone contact surface 113 disposed opposite proximal surface 111 that is configured to contact and rest upon a resected proximal tibia. As such, bone contact surface 113 is generally planar. However, in some embodiments, bone contact surface 113 may have curved ridges and/or a porous surface to facilitate secure registration with bone.

[0023] Stem or protruding portion 114 extends from baseplate portion 112 and may be sized to fit within an intramedullary canal of a tibia, which may or may not be reamed or otherwise resected to form a larger opening therein. Such fit may be a press fit. Alternatively, stem 114 may be sized to allow a bone cement mantle to be placed between stem 114 and the intramedullary canal and/or may have a porous outer surface to promote bone ingrowth or cement adhesion. An opening 118 extends through baseplate 112 and into stem 114. Opening 118 is sized to receive bearing bushing 120 therein.

[0024] Keel 116, which may be located on both lateral and medial sides of baseplate 112, extends between baseplate 112 and stem 114. Keel 116 helps prevent rotation of baseplate component 110 when implanted into bone.

[0025] Bearing bushing 120 is utilized when bearing component 140 is included as a separate component of baseplate component 110. Bearing bushing 120 is generally cylindrical and elongate and has an opening 122 extending therein along a longitudinal axis thereof. Opening 122 may extend entirely through bushing 120 or may extend partially therein. Opening 122 is sized to receive a bearing 142 of bearing component 140 (described further below) so that bearing 142 can rotate therein.

[0026] Tibial insert 130 includes an articular surface 132 that is concave in a sagittal plane such that articular surface 132 is higher at posterior and anterior extents thereof than at a location between such extents. Additionally, articular surface 132 at the anterior extent is generally higher or more proximal than articular surface 132 at the posterior extent. Also, the portion of articular surface 132 extending from the anterior extent toward the posterior extent generally has a steeper slope than the portion of articular surface 132 extending from the posterior extent toward the anterior extent. Moreover, an opening 134 extends through insert 130 sufficiently large to receive bearing 142 of bearing component 140 and for bearing 142 to rotate therein.

[0027] Bearing component 140 may be a separate component that is part of the tibial component, or bearing component may be integrally formed with baseplate component 110. Bearing component 140 generally includes an articular portion 144, a bearing 142 extending from articular portion 144, and a head portion 145 extending from articulating portion 144 in a direction opposite that of bearing 142. Bearing 142 is substantially cylindrical and elongate so as to extend through tibial insert 130 and into bearing bushing 120 while being rotatable therein.

[0028] Articulating portion 144 includes a convex articular surface 146 corresponding to the concavity of articular surface 132 of tibial component 130. In addition, the thickness of articulating portion 144 is generally greater at a posterior extent thereof than at an anterior extent thereof. This is at least partially due to articular surface 146 having a greater slope at an anterior extent thereof than the posterior extent thereof.

[0029] Head portion 145 is semi-rectangular and rounded at a proximal end thereof. Head portion 145 is sized to be received within a recess 146 of femoral component 180. Head portion 145 also includes a first opening 147 which extends through an anterior surface thereof in an anterior/posterior direction. This first opening 147 is sized to receive post 16 of guide 10 and bumper extension 152 of bumper 150. Head portion 145 also includes a second opening 148 which extends through lateral and medial surfaces thereof in a lateral/medial direction transverse to first opening 147. Second opening 148 is preferably disposed more proximal than first opening 147 and is sized to receive axle 160. Additionally, in some embodiments, particularly in embodiments where bumper extension 152 is notched (described further below), first openings 147 may at least partially intersect second opening 148.

[0030] In some embodiments, baseplate component 110 does not include bearing component 140 and bearing bushing 120. In such an embodiment, tibial insert 130 remains part of the tibial component such that tibial insert 130 is the articular portion connected to baseplate 112 of baseplate component 110. In this regard, head 145 may be integral with and extend from baseplate portion 112 and articular potion (i.e. tibial insert 130). As such, insert 130 may have a notch or opening that allows head 145 to pass therethrough.

[0031] Bumper 150 includes a bumper portion 154 and bumper extension 152. Bumper portion 154 has a distal surface 156 configured to rest on a proximal surface of articulating portion 144 of bearing component 140 and a proximal surface 158 configured to abut a distal anterior portion of femoral component 180. Bumper portion 150 may be made from resilient biocompatible materials which can absorb impact from femoral component 180 and compression between femoral component 180 and bearing component 140 over repeated cycles of knee hyperextension.

[0032] Bumper extension 152 is substantially cylindrical and sized to extend within first opening 147 of bearing component 140. Bumper extension 152 may also include a rounded notch (not shown) on a proximal surface thereof extending in a direction transverse to a longitudinal axis of bumper extension 152. Such notch may be shaped and positioned along bumper extension 152 so that when extension 152 is inserted into first opening 147 of bearing component 140, axle 160 can be inserted through second opening 148 and be partially disposed within the notch, thereby preventing extension 152 from being removed from first opening 147.

[0033] Axle 160 is substantially cylindrical and is sized to be received by axle bushings 170 and second opening 148 of bearing component 140.

[0034] Axle bushings 170 are also cylindrical and have openings 172 extending therethrough along a length thereof. Bushings 170 also include a flange 174 at one end thereof. Bushings 170 are sized to fit within transverse openings 184 of femoral component 180 (described further below) while flange 174 is sized to prevent such bushings 170 from passing all the way through transverse openings 184.

[0035] Femoral component 180 generally includes inner bone contact surfaces, a stem portion 188, a recess 186, transverse openings 184, and a distal surface 190. Generally TKA prostheses include five inner contact surfaces each corresponding with one of a posterior, anterior, distal, anterior chamfer, and posterior chamfer resected surfaces of a distal femur. While a femoral component according to the present invention can have five of such inner surfaces, femoral component 180 includes three inner contact surfaces in order to allow for femoral component 180 to have sufficient thickness at a posterior portion thereof for transverse openings 184 to extend therethrough.

[0036] Stem portion 188 extends from the second and/or third surfaces and may include an opening therein for receipt of a modular stem (not shown). Stem portion 188 may have a porous outer surface to promote bony ingrowth or cement adhesion.

[0037] Recess 186 extends through a posterior portion of femoral component 180 adjacent to stem portion 188 and through first inner surface 181. Recess 186 at least partially defines first (lateral) and second (medial) condylar portions 185 and 187. First and second condylar portions 185, 187 each define a curved distal surface. The curved distal surface of first and second condylar portions 185, 187 may be a convex curvature.

[0038] Transverse openings 184 extend through first and second condylar portions 185, 187 and intersect recess 186. Openings 184 are aligned such that they are concentric with each other and are sufficiently large to receive axle bushings 170 while being smaller than flanges 174 of axle bushings 170.

[0039] Distal surface 190 is curved in a sagittal plane and is primarily configured for articulation with a patella or patellar prosthesis. As such, distal surface 190 may have an intercondylar groove for patellar tracking to prevent lateral or medial subluxation of a patella. The distal surface 190 of femoral component 180 and the distal surfaces of the first and second condylar portions 185, 187 may include a plurality of portions each defined by a different radius of curvature. The distal surface of the first and second condylar portions 185, 187 may each have an anterior section and a posterior section. The anterior section may be curved such that it defines a first radius of curvature. The posterior section may be curved such that it defines a second radius of curvature different than the first radius of curvature. An exemplary femoral component having multiple radii of curvature can be found in U.S. Publication No. 2017/0035572, the disclosure of which is incorporated by reference herein in its entirety.

[0040] FIGS. 1 and 2A-2C depict the assembly guide 10. Assembly guide 10 is configured for aligning a femoral component and tibial component of a hinge knee prosthesis such that an axle can be easily connected thereto, as described in more detail below. In this regard, guide 10 is configured to be inserted between femoral component 180 and the tibial component and serves as a temporary shim or wedge to assist in assembling the final implant, such as when at a 90 degree angle of flexion, for example.

[0041] Guide 10 generally includes first and second body portions 24, 26, first and second wedge portions 12, 14, and a bridge 22. Bridge 22 is connected to and extends between first and second body portions 24, 26. First and second wedge 12, 14 are respectively connected to first and second body portions 24, 26 and extend in a first direction therefrom. The first and second wedges 12, 14 are separated by a recess 28. Recess 28 is configured for receipt of head portion 145 of the bearing component 140, as discussed below. As mentioned above, Bridge 22 is connected to and extends between the first and second body portions 24, 26. In this regard, bridge 22 at least partially defines recess 28.

[0042] First and second wedges 12, 14 each have a thickness defined between a respective proximal surface 18, 20 and distal surface 13, 15 and extend in a second direction transverse to the first direction. According to the depicted embodiment, the first direction is a posterior direction such that first and second wedges 12, 14 respectively extend posteriorly from first body portion 24 and second body portion 26. The thicknesses of wedge portions 12, 14 are configured such that they can be wedged between femoral component 180 and the tibial component so as to support femoral component 180 and so that wedge portions 12, 14, by virtue of their thicknesses, align openings 148 and 184 to allow axle 160 to be easily advanced therein.

[0043] To help facilitate support of femoral component 180, in this regard, proximal surfaces 18, 20 of first and second wedges 12, 14 are curved so as to correspondingly engage a respective condyle of a femoral component, when guide 10 is positioned between femoral component 180 and the tibial component. Thus, curved proximal surfaces 18, 20 have a geometry configured to correspond to the geometry of distal surface 190 of femoral component 180 such that the curved proximal surfaces 18, 20 correspond to a curvature of respective condyles of femoral component 180, such as when at a 90 degree angle of femoral flexion, for example. According to one embodiment, the curved proximal surfaces 18, 20 each have a concave curvature equal to a radius of curvature of a convex distal surface of the condylar portions of femoral component 180. Where femoral component 180 includes multiple curved portions that each have their own respective radius of curvature different from the other, curved proximal surfaces 18, 20 may be curved to correspond to one of such curved portions. For example, where distal surface 190 of femoral component 180 has an anterior curved portion and a posterior curved portion each with a different radius of curvature, curved proximal surfaces 18, 20 may have a curvature corresponding to that of the posterior portion. In this respect, curved proximal surfaces 18, 20 would be congruent with a posterior aspect of respective condyles 185 and 187, but would be incongruent with an anterior aspect of such condyles 185, 187. Thus, curved surfaces 18, 20 may only fully engage femoral component 180 when femoral component 180 is at a particular flexion angle relative to the tibial component, as best shown in FIG. 3A. Such flexion angle may be 90 degrees for example. In this regard, guide 10 may constrain femoral component 180 relative to the tibial component during assembly of axle 160 which may make assembling axle 160 to such components easier. In addition, curved surfaces 18, 20 being congruent to a posterior aspect of femoral component 180 and incongruent relative to an anterior aspect helps align openings 148 and 184 in an anteroposterior direction as well as a superior-inferior direction since full engagement of guide 10 is achieved in a particular alignment between femoral and tibial components and allows the surgeon to identify when such alignment is achieved.

[0044] Distal surfaces 13 and 15 are configured to engage and rest upon a proximal end of the tibial component. Thus, in the embodiment depicted, distal surfaces 13 and 15 are configured to engage a proximal side of articular portion 144 of bearing component 140 and, thus, may be planar. However, in other embodiments where femoral component 180 directly articulates with tibial insert 130, distal surfaces 13 and 15 may be convexly curved similar to articular surface 146 so as to correspond to the concave curvatures of insert 130 so that guide 10 can rest directly upon insert 130. In even further embodiments, distal surfaces 13 and 15 may be configured to rest directly upon a proximal surface of baseplate portion 112.

[0045] Guide also includes a post 16 extending from bridge 22. Post 16 extends in the same direction as first and second wedges, 12, 14 such that post 16 extends in a posterior direction into recess 28. Post 16 is substantially cylindrical and sized to extend within an opening 147 of head 145, discussed in more detail below. However, in some embodiments, post may be rectangular shaped or the like.

[0046] FIGS. 3A and 3B depict guide 10 positioned between femoral component 180 and the tibial component in a fully engaged position. More particularly, guide 10 is positioned between bearing component 140 and femoral component 180 such that wedge portions 12 and 14 are disposed between respective condyles 185, 187 of femoral component and bearing component 140 and so that distal surface 190, as defined by such condyles 185 and 187, congruently engage curved proximal surfaces 18, 20 of guide 10. In the embodiment depicted, such congruent contact occurs when femoral component 180 is at a flexion angle of 90 degrees relative to the tibial component. Moreover, post 16 is received in post opening 147 of head 145. When post is fully received within post opening 147, the surgeon is assured that guide 10 has appropriately positioned femoral component 180 the anteroposterior direction relative to head 145 so that openings 148 and 184 align in the anteroposterior direction. Post 16 also helps prevent unintended movement of femoral component 180 relative to head 145. The thicknesses of wedge portions 12 and 14 further align femoral component 180 relative to head 145 in a superior-inferior direction so that openings 148 and 184 align in such direction. Thus, in this position, axle 160 may be easily slide into openings 148 and 184.

[0047] In a method of assembling prosthesis 100, femoral component 180 is connected to a resected distal femur and baseplate component 110 is connected to a proximal tibia. Bearing bushing 120 is inserted into opening 118 of baseplate component 110. Tibial insert 130 is then attached to proximal surface 111 of baseplate 112. Thereafter, bearing 142 is inserted through opening 134 in tibial insert 130 and into bearing bushing 120 until articular surface 146 of bearing component 140 contacts articular surface 132 of tibial insert 130. The convexity of articular surface 146 of bearing component 140 and concavity of articular surface 132 of tibial insert 130 help bearing component 140 settle into proper alignment.

[0048] Axle bushings 170 are inserted into respective transverse openings 184 of femoral component 180 such that flanges 174 face each other and are disposed adjacent to intercondylar recess 186. The head portion 145 of the tibial component is positioned into the intercondylar recess 186 of femoral component 180. Guide 10 is then inserted between baseplate component 110 and femoral component 180. As guide 10 is inserted between tibial component and femoral component, post 16 of guide 10 is inserted into post opening 147 of bearing component 140.

[0049] Inserting guide 10 between baseplate component 110 and femoral component 180 includes wedging guide 10 between the baseplate component 110 and femoral component 180 so that proximal surfaces 18, 20 of guide 10 support femoral component 180 and the distal surfaces 13, 15 of guide 10 rest on component 140, as best shown in FIGS. 3A and 3B. However, prior to inserting guide 10 into the space between femoral component 180 and component 140, femur, along with femoral component 180, may be positioned at 90 degrees of flexion relative to the tibia or any other appropriate flexion angle. As femoral component 180 is supported by the proximal surfaces 18, 20 of guide 10, first and second condylar portions 185, 187 are seated on first and second wedges 12, 14, respectively. The curvature of the distal surface of the first and second condylar portions 185, 187 may be such that femoral component 180 can only be seated properly on guide 10 at one angle of flexion. The angle of flexion may be 90 degrees.

[0050] After guide 10 is inserted between baseplate component 110 and femoral component 180, transverse openings 184 of femoral component 180 are aligned with second opening 148 of the femoral component. Axle 160 is then inserted through axle bushings 170 and bearing component 140, thereby coupling femoral component 180 to the tibial component. Guide 10 is then removed and bumper 150 may be inserted in its place. Bumper 150 helps prevent hyperextension of femoral component 190.

[0051] The above described system includes a hinge knee prosthesis 180 in which condyles 185, 187 of the femoral component 190 do not directly articulate with the tibial component, such as with the tibial insert 130. In this regard, when guide 10 is used to align femoral component 180 with the tibial component for receipt of axle 160, guide 10 is positioned between femoral component 190 and articular portion 144 of bearing component 140 such that guide 10 rests on articular portion 144, which itself articulates with insert 130. However, it should be understood that guide 10 can work with other hinge knee configurations. For example, in some embodiments, a femoral component, such as component 180, may have condyles that directly contact and articulate with a tibial insert, such as insert 130. In such embodiments, there may be no articular portion 144. Thus, guide 10 may be configured, as described above, to rest on the tibial insert while supporting the femoral component so that an axle can be connected thereto. In such embodiments, guide 10 may or may not include post 16.

[0052] In another method of assembling a hinge knee prosthesis in which embodiments as immediately described above are assembled, a bearing component that includes a bearing and head, such as bearing 142 and head 145, but without portion 144, is connected to baseplate component 110. In such an embodiment, head 145 would extend from the proximal most surface of baseplate component 110. Head 145 is similarly inserted into the intercondylar space 186 of femoral component 180. However, unlike in the method described above, insert 10 is inserted between the tibial component and femoral component 180 so that guide 10 rests on the tibial insert, such as insert 130 or another insert that includes discrete concave condylar portions as is generally understood in the art. Femoral component 180 may similarly be positioned at a predetermined angle of flexion for guide 10 to effectively operate. Once a head opening 148 and opening 184 are aligned, axle 160 may be inserted to connect femoral component 180 to the tibial component 110.

[0053] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.