US20090287309A1 - Intra-articular joint replacement - Google Patents

Abstract

A method for implanting an intra-articular shoulder prosthesis is provided. The method includes removing a proximal portion of a humerus. The proximal portion of the humerus preferably forms a resected portion. The resected portion has a convex outer surface and an inner surface. The method further includes engaging the convex outer surface of the resected portion with a cut surface of the proximal portion of the humerus. The cut surface of the proximal portion of the humerus and/or the inner surface of the resected portion are optionally processed to form a generally concave surface, such as by impacting. In one embodiment, the inner surface of the resected portion is impacted into engagement with the cut surface of the proximal portion of the humerus. The generally concave inner surface of the resected portion forms a concave articular surface to receive an interpositional implant.

Description

CROSS REFERENCE TO RELATED APPLICATIONS
• The present application is a continuation-in-part of U.S. patent application Ser. No. 12/020,913 filed Jan. 28, 2008, which claims priority to French application no. 0700622, entitled Méthode et ensemble d'instrumentation chirurgicale pour poser une prothése totale d'épaule inversée, et prothése correspondante, filed Jan. 30, 2007, and also claims the benefit of U.S. Provisional Application Ser. Nos. 60/888,437 filed Feb. 6, 2007 and 60/971,762 filed Sep. 12, 2007, both entitled Method And Apparatus For Fitting An Inverted Shoulder Prosthesis, and U.S. Provisional Application Ser. No. 61/015,042, entitled Intra-Articular Joint Replacement, filed Dec. 19, 2007, the complete disclosures of which are hereby incorporated by reference.
TECHNICAL FIELD
• The present invention relates to a method and apparatus for implanting a prosthesis at the intersection of two or more bone, and in particular, to a method and apparatus for processing and implanting a resected portion of a humerus to act as an articular surface for an interpositional implant of a shoulder prosthesis.
BACKGROUND OF THE INVENTION
• In the field of total shoulder prostheses, prostheses are commonly said to be inverted when they comprise a glenoid component that is integral with the glenoid surface of a scapula of a patient's shoulder and that delimits a convex articular surface and a humeral component that is integral with the humerus of the patient's shoulder and that delimits a concave articular surface. The cooperation of the articular surfaces of the glenoid and humeral components allow an articulated connection to be reproduced at the shoulder. However, it is common with this type of prosthesis that during adductive movement of the shoulder, the lower portion of the humeral prosthetic component strikes the pillar of the scapula, i.e. the lower portion of the glenoid located just below the glenoid prosthetic component (when the patient is standing upright). This interference between the humeral prosthetic component and the scapula limits the range of adductive movement of the shoulder and may cause pain to the patient or even lead to the prosthesis becoming dislodged due to, for example, osteolysis of the scapula.
• Another method used to replace damaged shoulder joints is interpositional arthroplasty. The method of interpositional arthroplasty uses tissue from the patient or an artificial replacement to repair a damaged or malformed joint. An interpositional implant is positioned at the joint to act as an engagement surface between two adjacent bone structures to allow articular movement. In the particular field of interpositional shoulder arthroplasty, the humeral metaphysis is typically impacted to form an engagement surface for an interpositional implant positioned between a glenoid component (or glenoid) and a humeral component (or humeral metaphysis). However, if the cancellous bone in the humeral metaphysis is of poor or degraded quality, the cancellous bone may lead to gradual subsidence of the interpositional implant within the humeral metaphysis. It is thus desirable to develop an interpositional implant with a metaphyseal articular surface that will provide support and protection to the metaphyseal cancellous bone.
SUMMARY OF THE INVENTION
• The present invention relates to a method and apparatus for forming a prosthesis at the intersection of two or more bones. A proximal or distal portion of a bone is removed, comprising a resected portion with an outer convex surface and an inner surface. The inner surface of the resected portion is processed, comprising a concave articular surface. The outer convex surface of the resected portion is implanted in a cut surface of the bone. In one embodiment, an interpositional implant is positioned in the concave articular surface that engages with the adjacent bone. In another embodiment, a convex portion of an adjacent bone or another implant is provided that engages with the concave articular surface. In some embodiments, the ends of both bones forming the intersection are processed as disclosed herein.
• On embodiment of the present invention includes a method for implanting a shoulder prosthesis. The method includes removing a proximal portion of a humerus. The proximal portion of the humerus preferably forms a resected portion. The resected portion has a convex outer surface and an inner surface. The method further includes engaging the convex outer surface of the resected portion with a cut surface of the proximal portion of the humerus. The cut surface of the proximal portion of the humerus and/or the inner surface of the resected portion are optionally processed to form a generally concave surface, such as by impacting. In one embodiment, the inner surface of the resected portion is impacted into engagement with the cut surface of the proximal portion of a humerus. In one embodiment, the generally concave inner surface of the resected portion forms a concave articular surface to receive an interpositional implant. In another embodiment, a convex glenoid implant is located in the scapula and engages with the concave articular surface.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
• FIG. 1A is a schematic view of an intra-articular prosthesis implanted in a patient's shoulder in accordance with an embodiment of the present invention.
• FIG. 1B is a schematic view of an alternate prosthesis implanted in a patient's shoulder in accordance with an embodiment of the present invention.
• FIG. 2 is a schematic view of a cutting guide for a proximal portion of a humerus in accordance with an embodiment of the present invention.
• FIG. 3 is a schematic view of a resected portion of the proximal portion of the humerus in accordance with an embodiment of the present invention.
• FIG. 4 is a schematic view of a method of preparing a resected proximal portion of the humerus in accordance with an embodiment of the present invention.
• FIG. 5 is a schematic view of a method and apparatus for implanting the resected portion of the proximal portion of the humerus in accordance with an embodiment of the present invention.
• FIG. 6 is a schematic view of a resected portion implanted into a proximal portion of the humerus in accordance with an embodiment of the present invention.
• FIG. 7 is a schematic view of a resected portion implanted into a proximal portion of the humerus using fasteners in accordance with an alternate embodiment of the present invention.
• FIG. 8 is a schematic view of a resected portion implanted into a proximal portion of the humerus using sutures in accordance with an alternate embodiment of the present invention.
• FIG. 9 is a schematic view of an interpositional implant engaged with an implanted resected portion in accordance with the present invention.
• FIG. 10 is a schematic view of intra-articular prostheses implanted in a patient's hand in accordance with an embodiment of the present invention.
• FIG. 11 is a schematic view of intra-articular prostheses implanted in a patient's foot in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
• FIG. 1A shows a schematic view of aprosthesis10 including aglenoid component12, ahumeral component14 and aninterpositional implant16. Theglenoid component12 is implanted in the scapula S of the gleonid G. The method and apparatus of the various embodiments of the present invention disclosed herein may be used with a variety of glenoid components, such as for example those disclosed in U.S. Pat. Nos. 7,033,396; 6,953,478; 6,761,740; 6,626,946; 5,702,447 and U.S. Publication Nos. 2004/0220673; 2005/0278030; 2005/0278031; 2005/0278032; 2006/0020344, which are hereby incorporated by reference. Although theprosthesis10 is primarily discussed as being implanted in a patient's shoulder, theprosthesis10 may also be modified and implanted in other locations of a patient's body without departing from the intended scope of the present invention. For example, theprosthesis10 may be modified to be implanted in a patient's hip, ankle, hands, or feet.
• In the illustrated embodiment, theglenoid component12 includes anarticular member18 with a generally concavearticular surface20 that engages theinterpositional implant16. Given that thearticular member18 is positioned immediately adjacent the glenoid G, theinterpositional implant16 is remote from the resected surface of the glenoid G in the sense that, if thearticular member18 were omitted, theinterpositional implant16 would be directly juxtaposed with the glenoid G. Thus, on account of thearticular member18, theinterpositional implant16 and thehumeral component12 are laterally remote from the glenoid G, limiting the risk of the humerus H interfering with the bottom of the glenoid G, i.e. with the pillar P of the scapula S. Alternatively, anarticular member18 may not be required within the glenoid G. In this case, theinterpositional implant16 would articulate directly with the glenoid G.
• Thehumeral component14 includes anarticular member24 formed from a resected portion30 (shown inFIG. 3) of the proximal humerus PH that is removed during processing of the humerus H. The proximal humerus PH is preferably resected such that the resectedportion30 is preferably a single, unitary piece. In this form, anouter convex surface58 of the resectedportion30 is implanted into the proximal humerus PH as a single unit, rather than as fragments.
• Alternatively, the resectedportion30 can be formed from a single piece or a plurality of pieces taken from the proximal humerus PH or other locations in the patient's body. Implantation of the resectedportion30 can be supplemented with bone graft material, such as for example a purée of bone substance, bone replacements, bone fillers, bone cements and/or bone adhesives, or a combination thereof. The bone graft material can be formed from the patient's bone, an allograft, a xenograft, or a combination thereof. Various bone replacements, bone fillers, bone cements and bone adhesives are disclosed in U.S. Pat. No. 6,692,563 (Zimmerman), which are hereby incorporated by reference. Various additives can also be included with the resected portion, including, but not limited to bone growth agents and pain inhibitors.
• As will be discussed further below, the resectedportion30 is prepared and impacted into the proximal humerus PH to form thearticular member24 having a concavearticular surface32. The preparation of the resectedportion30 can be performed ex vivo or in situ.
• In the illustrated embodiment, thehumeral component14 includes anoptional stem22 located in the medullary cavity M of the humerus H. The proximal end28 of thestem22 supports the resectedportion30 and optionally serves as an attachment member. For example, afastener26 can optionally extend through the resectedportion30 and engage thestem22. It will be appreciated that thestem22 may be omitted entirely without departing from the intended scope of the present invention.
• Theinterpositional implant16 is positioned between thearticular member18 of theglenoid component12 and thearticular member24 of thehumeral component14. The radius of theinterpositional implant16 is typically equal to or less than the radii of theconcave surfaces20 and32 of thearticular member18 of theglenoid component12 and thearticular member24 of thehumeral component14, respectively. When theinterpositional implant16 is positioned between theglenoid component12 and thehumeral component14, as shown inFIG. 1A, theconcave surfaces20 and32 are in mutual surface contact with theinterpositional implant16, allowing articular movements of the patient's shoulder.
• In an alternate embodiment illustrated inFIG. 1B, theinterpositional implant16 is eliminated and aglenoid component18 with a convexarticular surface19 is substituted. Thearticular member24, created as outlines inFIG. 1A, engages directly with the convexarticular surface19.
• FIGS. 2-9 illustrate various embodiments for processing and implanting theprosthesis10 into the humerus H. It is to be understood that the method of implanting theprosthesis10 described hereinafter is merely a non-limiting illustrative example of a method and instruments used to implant theprosthesis10. In other words, the method and the instruments specified hereinafter can be used to implant prostheses of a broad range of structures, of which, for example, the glenoid and/orhumeral components12,14 consist of a plurality of metallic, plastic and/or ceramic-type parts joined together. As previously mentioned, theinterpositional implant16 may also articulate directly with the glenoid G such that theglenoid component12 is not included as part of theprosthesis10.
• FIG. 2 is a schematic view of a cuttingguide34 positioned over the proximal humerus PH. In order to prepare the proximal humerus PH for resection, the soft parts (i.e. cartilage) of the proximal humerus PH may optionally be removed using a deltopectoral or supero-external approach.
• The cuttingguide34 includes a bell-shapedbody36 secured to ashaft38. An interior surface of thebody36 has a concave surface from which the main center of curvature pertains substantially to anaxis40 from which theshaft38 extends from thebody36. Thebody36 is designed to cover the upper portion of the proximal humerus PH in the manner of a cap and is perforated to give the surgeon a better view of the proximal humerus PH when positioning thebody36. Thebody36 is thus shaped to reproduce approximately the surface features of the upper proximal humerus PH of a normal anatomical humerus H. However, in practice, there will be a range of a plurality ofhomothetic guiding instruments34 havingbodies36 which have respective dimensions associated with the size and the state of the patient's bones.
• Theshaft38 of the cuttingguide34 is optionally provided with a protrudingtube42 centered on theaxis40 and the main center of curvature of thebody36. Once thebody36 is properly positioned over the proximal humerus PH, aguide pin44 having a pointed distal end is introduced into the protrudingtube42 and inserted into the proximal humerus PH. Theguide pin44 preferably terminates before the cutting plane C-C′. The surgeon uses thedistal surface27 on thebody36 located in the cutting plane C-C′ to resect theportion30 from the proximal humerus PH. Alternatively, the surgeon can cut free-hand without a template.
• FIG. 3 shows a schematic view of the resectedportion30 of the proximal humerus PH. After the proximal humerus PH has been resected, the proximal humerus PH has acut surface66 where the resectedportion30 was removed. The resectedportion30 includes a convexouter surface58 and aninner cut surface50 ofcancellous bone52. In one embodiment, the resectedportion30 is prepared ex vivo by impacting theinner cut surface50 to compress thecancellous bone52 to form the generally innerconvex surface32. As a result, the innerconvex surface32 is a layer of compactedcancellous bone52 pressed against theinner surface54 of thecortical bone56.
• In another embodiment, the resectedportion30 is prepared ex vivo by removing thecancellous bone52 from thecortical bone56. As a result, the innerconvex surface32 is essentially theinner surface54 of thecortical bone56. Either of these procedures can also be performed in situ. That is, after the resectedportion30 is engaged with the proximal humerus PH.
• In some embodiments, thecut surface66 of the proximal humerus PH is prepared to receive the resectedportion30. Ahemispherical reaming instrument64, shown inFIG. 4, is used to form aconcave surface60 in the proximal humerus PH. The reaminginstrument64 includes aconvex body68 having a plurality ofteeth70 to shape thecut surface66 into the desired form. Theconcave surface60 is preferably the same shape as the outerconvex surface58 of the resectedportion30.
• In another embodiment, the cut surface66 (shown in dashed lines) is compacted or carved to form theconcave surface60 on the proximal humerus PH. Preparing thecut surface66 of the proximal humerus PH may be performed using a variety of other techniques known in the art without departing from the intended scope of the present invention. Small holes may optionally be drilled through theconcave surface60 to enhance bone integration remodeling once the resectedportion30 is reversed and implanted in the humerus H.
• FIG. 5 shows the resectedportion30 being impacted into engagement with theconcave surface60 of the proximal humerus PH. The resectedportion30 is positioned within theconcave surface60 such that the convexouter surface58 engages theconcave surface60. An impactinginstrument78 is then used to drive the resectedportion30 into the proximal humerus PH to form thearticular member24 having a semi-spherical shape at theconcave surface60 of the proximal humerus PH. As the resectedportion30 is driven into the proximal humerus PH, cancellous bone at each side of the proximal humerus PH is compressed and forms to the shape of theconcave surface60.
• In an alternate embodiment illustrated inFIG. 6, the resectedportion30 is compacted directly against thecut surface66, without the reaming step shown inFIG. 4. By gradually integrating the resectedportion30 into the proximal humerus PH, a strong bony or fibrous-cartilaginous underlying support structure having theconcave surface60 is created to support thearticular member24. In addition, the resectedportion30 is used to isolate thecancellous bone67 in the humerus H from synovial fluids. The resectedportion30 is preferably driven into the proximal humerus PH as a single unit such that the resultingarticular member24 is an integral piece and is not formed of fragmented pieces. Thearticular member24 has a shape of a metaphyseal cup formed to cooperate with a variety of interpositional components, such as, for example, a full sphere, a lens-type free interpositional component, or a combination thereof. In one embodiment, thearticular member24 may have a shape of approximately one-third of a sphere.
• FIG. 7 shows a schematic illustration of one embodiment of attachingarticular member24 to theconcave surface60 of the proximal humerus PH using a plurality ofpins80. Theheads82 of thepins80 are preferably flush with, or recessed below, the concaveinner surface32. Various bone anchors, known in the art, may also be used in place of thepins80. Thepins80 may be formed of various materials, including, but not limited to: metallic components and polymeric components. In particular, thepins80 may be formed of bioresorbable polymers. Thepins80 are particularly useful when the resectedportion30 includes a plurality ofpieces30A,30B,30C.
• In one embodiment, asuture material84 is optionally attached to one or more of thepins80. Thesuture material84 extends through the proximal humerus PH to the opposite side and is anchored to thecortical bone86 using conventional techniques. Thesuture material84 operates as a tension member to retain the resectedportion30 to theconcave surface60 of the proximal humerus PH.
• In an alternate embodiment illustrated inFIG. 8, the resectedportion30 is attached to the proximal humerus PH using a plurality ofperipheral sutures90. Thesutures90 may be formed of various materials, including, but not limited to: metallic components and polymeric components. In particular, thesutures90 may be formed of bioresorbable polymers. The resectedportion30 may be fixed within the proximal humerus PH by any fixation mechanism, or combination of fixation mechanisms, known in the art without departing from the intended scope of the present invention.
• In one embodiment, a reinforcingstructure92, such as for example reinforcing fibers, a three-dimensional porous matrix or scaffold, is located between theconcave surface60 on the proximal humerus PH and the resectedportion30. In the illustrated embodiment, the reinforcingstructure92 is attached to thecortical bone86 of the proximal humerus PH by thesutures90. In one embodiment, the reinforcingstructure92 operates like a sling to limit further penetration of the resectedportion30 into the proximal humerus PH. In another embodiment, the reinforcingstructure92 promotes in-growth between the proximal humerus PH and the resectedportion30. Examples of such reinforcing structures include a porous matrix, a scaffold, a reticulated bioceramic framework, a structured porous tantalum and a synthetic fiber mesh. Various porous matrices and scaffoldings are disclosed in U.S. Pat. Nos. 4,479,271; 6,511,511; 6,605,117; 6,797,006; 6,902,584; and 7,250,550, which are hereby incorporated by reference. Although the reinforcingstructure92 is discussed as being used in conjunction with the resectedportion30, the reinforcingstructure92 may alternatively be used in place of the resectedportion30 as an articular surface for engaging the interpositional implant16 (shown inFIGS. 1 and 9).
• In another embodiment, the reinforcingstructure92 extends beyond thesutures90. The reinforcingstructure92 may be made of any material, natural and synthetic, suitable for implantation. Preferably the reinforcingstructure92 is flexible to permit conformity with the proximal humerus PH. The reinforcingstructure92 material may also permit intraoperative cutting or other shaping of the reinforcingstructure92 to fit a surgical site. For example the reinforcingstructure92 may be intraoperatively shapeable by cutting with scissors. The reinforcingstructure92 may include natural tissues including fibrocartilage, fascia, pericardium, and/or other natural tissues. The reinforcingstructure92 may include synthetic materials including metals, polymers, ceramics, hydrogels and/or other suitable materials. Apolymer reinforcing structure92 may include resorbable and/or non-resorbable polymers. Examples of resorbable polymers include polylactic acid polymers, polyglycolic acid polymers, and/or other suitable resorbable polymers. Examples of non-resorbable polymers include polyolefins, polyesters, polyimides, polyamides, polyacrylates, polyketones, and/or other suitable non-resorbable polymers. Ametal reinforcing structure92 may include titanium, tantalum, stainless steel, and/or other suitable metals and alloys thereof. For example metal fibers may be woven into a porous flexible reinforcingstructure92.
• The reinforcingstructure92 may be attached to the hard and/or soft tissues of the proximal humerus PH bymechanical fasteners94, adhesives, tissue in-growth, and/or other suitable attachment mechanism. The attachment mechanism may be permanent and/or bioabsorbable. For example, the reinforcingstructure92 may be screwed, pinned, sutured, or stapled to the bone and/or soft tissue adjacent the joint. The reinforcingstructure92 may include preformed openings for receiving fasteners. The reinforcingstructure92 may include a reinforced edge to strengthen the reinforcingstructure92 against pullout of fasteners. For example, the edge may be reinforced by hemming, molding, braiding, embedding a cord, and/or by other suitable reinforcement mechanism. The reinforced edge may form a thicker portion of the reinforcingstructure92.
• FIG. 9 shows theinterpositional implant16 positioned within thearticular member24 at theconcave surface60 of the proximal humerus PH. Referring again also toFIG. 1A, once thearticular member24 is fixed onto the proximal humerus PH or thestem22 and thearticular member18 is fixed onto the glenoid G, theinterpositional implant16 is positioned between thearticular member24 and thearticular member18. In one embodiment, theinterpositional implant16 is a sphere or ball having a continuousconvex surface104. The interaction of theconvex surface104 of theinterpositional implant16 with the concavearticular surface32 of thearticular member24 and theconcave surface20 of thearticular member18 allows articulation of theprosthesis10. The size of theinterpositional implant16 is selected such that theconvex surface104 of theinterpositional implant16 is engageable with both theconcave surface20 of thearticular member18 and the concavearticular surface32 of thearticular member24. In one embodiment, theinterpositional implant16 is formed of a polymeric material, metal, ceramic, or a combination thereof. In one embodiment, theinterpositional implant16 is coated with pyrolytic carbon such as that described in U.S. Pat. No. 6,436,146 (Hassler et al.) which is hereby incorporated by reference. AlthoughFIG. 9 depicts theinterpositional implant16 as a sphere, theinterpositional implant16 may have any shape having at least two convex surfaces, such as a disc. The disc may articulate directly with the glenoid G and the humerus H without the need forarticular member18 ofglenoid component12 orarticular member24 ofhumeral component14. In another embodiment, the interpositional implant may be replaced by a glenosphere formed of pyrolytic carbon. For example, a convex surface of the glenosphere, or reversed glenoid prosthesis, may be adapted to articulate directly with the reversed, concave surface of the humerus H, and thus eliminate the need for an interpositional implant.
• As previously mentioned, the method of resecting natural bone and compacting the resected surface of the natural bone with the resected portion to form a concave articular surface for engagement with a convex articular surface of an interpositional implant to repair or replace a damaged joint is not limited to repairing or replacing a damaged shoulder.
• FIG. 10 shows a hand having a firstinterpositional implant100 implanted betweenmetacarpal102 andproximal phalange104. Thedistal end120 of the metacarpal102 is resected and processed in a manner similar to the resection and processing of the glenoid andhumeral components12 and14 (shown inFIG. 1A) described above, to create a concavearticular surface122. In the illustrated embodiment,proximal end124 of theproximal phalange104 is also resected and processed to create concavearticular surface126.
• FIG. 10 also illustrates asecond interpositional implant106 implanted betweenmetacarpal108 andproximal phalange110, and a thirdinterpositional implant112 implanted betweenproximal phalange114 andintermediate phalange116. Thebones102,104,108,110,114 and116 adjacent the respectiveinterpositional implants100,106 and112 are preferably resected and processed in a manner similar to the resection and processing of the glenoid andhumeral components12 and14 (shown inFIG. 1A) described above. In some embodiments, a natural concave articular surface of one of the bones at the intersection, such as for example on theproximal end128 of theproximal phalange110, may be sufficient to retain theinterpositional implant106, making resection unnecessary. Theinterpositional implants100,106 and112 interact and function with the resected bones in a manner similar to theinterpositional implant16 described above.
• In another embodiment, theproximal end130 of theproximal phalange114 is resected and processed as discussed herein. The naturallyconvex surface132 of the metacarpal134 engages directly with the concavearticular surface136, without the need for an interpositional implant.
• As can be seen inFIG. 10, depending on the joint being repaired or replaced, the shape of theinterpositional implants100,106 and112 may be modified so that they are easily implantable between their respective components or bones. AlthoughFIG. 10 depicts interpositional implants between metacarpal bones and proximal phalanges and an interpositional implant between a proximal phalange and a middle phalange, an interpositional implant may be positioned at any joint in the hand, for example, between a middle phalange bone and a distal phalange bone or between the trapezium or scaphoid and a metacarpal bone.
• FIG. 11 shows a foot having a firstinterpositional implant200 implanted between ametatarsal202 and aproximal phalange204 and asecond interpositional implant206 implanted between theproximal phalange204 and adistal phalange208. Thebones202,204 and208 adjacent the respectiveinterpositional implants202 and206 are resected and processed in a manner similar to the resection and processing of the glenoid andhumeral components12 and14 (shown inFIG. 1A) described above. Likewise, theinterpositional implants202 and206 interact and function with the resected bones in a manner similar to theinterpositional implant16 described above.
• Similar to theinterpositional implants100,106 and112 depicted inFIG. 10, the shape of theinterpositional implants202 and206 may be modified so that they correspond to the shape of the resected bone structures within the foot. AlthoughFIG. 11 depicts an interpositional implant between a metatarsal bone and a proximal phalange and an interpositional implant between a proximal phalange and a middle phalange, an interpositional implant may be positioned at any joint in the foot, for example, between a proximal phalange and a middle phalange or between a middle phalange and a distal phalange. Any of the variations disclosed herein can be used with the embodiments ofFIGS. 10 and 11, such as for example, the reinforcing structure or fasteners.
• Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments descriconcave articular surface above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the descriconcave articular surface features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.

Claims (48)

1. A method of forming a prosthesis at the intersection of at least two bones, the method comprising the steps of:

removing a proximal or distal portion of a bone to comprise a resected portion with an outer convex surface and an inner surface;

processing the inner surface of the resected portion to comprise a concave articular surface;

implanting the outer convex surface of the resected portion in a cut surface of the bone; and

positioning an interpositional implant in the concave articular surface.

2. The method ofclaim 1 comprising the steps of:

positioning a cutting template on the bone; and

cutting the bone according to the cutting template.

3. The method ofclaim 1 wherein the step of processing the inner surface of the resected portion comprises compacting cancellous bone.

4. The method ofclaim 1 wherein the step of processing the inner surface of the resected portion comprises removing at least a portion of cancellous bone in the resected portion.

5. The method ofclaim 1 comprising the step of implanting the outer convex surface of the resected portion in the cut surface before processing the inner surface of the resected portion.

6. The method ofclaim 1 wherein the resected portion comprises a unitary structure.

7. The method ofclaim 1 comprising the step of compacting the cut surface of the bone to form a recess with a shape generally corresponding to the outer convex surface of the resected portion.

8. The method ofclaim 1 comprising the step of reaming the cut surface of the bone to form a recess with a shape generally corresponding to the outer convex surface of the resected portion.

9. The method ofclaim 1 comprising the steps of:

locating the outer convex surface of the resected portion on the cut surface of the bone; and

impacting the resected portion into the cut surface of the bone.

10. The method ofclaim 1 wherein the step of implanting the resected portion comprises the step of arranging a plurality of pieces of the resected portion in the cut surface of the bone.

11. The method ofclaim 1 comprising attaching the resected portion to the cut surface of the bone using one or more of fasteners, bone anchors, or sutures.

12. The method ofclaim 1 comprising the step of locating a reinforcing structure between the outer convex surface of the resected portion and the cut surface of the bone.

13. The method ofclaim 1 comprising the steps of:

positioning a reinforcing structure across at least a portion of the cut surface of the bone; and

attaching the reinforcing structure to the bone.

14. The method ofclaim 1 comprising selecting the interpositional implant from one of a sphere or a disc.

15. The method ofclaim 1 comprising coating the interpositional implant with pyrolytic carbon.

16. The method ofclaim 1 comprising drilling apertures in the cut surface before implanting the resected portion.

17. The method ofclaim 1 wherein the bone comprises a proximal portion of a humerus.

18. A method of forming a shoulder prosthesis, the method comprising the steps of:

removing a proximal portion of a humerus to comprise a resected portion with an outer convex surface and an inner surface;

processing the inner surface of the resected portion to comprise a concave articular surface;

implanting the outer convex surface of the resected portion in a cut surface of the proximal portion of the humerus; and

positioning an interpositional implant in the concave articular surface.

19. The method ofclaim 18 comprising the steps of:

positioning a cutting template on the proximal portion of the humerus; and

cutting the proximal portion of the humerus according to the cutting template.

20. The method ofclaim 18 wherein the step of implanting the resected portion comprises the step of arranging a plurality of pieces of the resected portion in the cut surface of the proximal portion of the humerus.

21. The method ofclaim 18 comprising attaching the resected portion to the cut surface of the proximal portion of the humerus using one or more of fasteners, bone anchors, or sutures.

22. The method ofclaim 18 comprising the step of locating a reinforcing structure between the outer convex surface of the resected portion and the cut surface of the proximal portion of the humerus.

23. The method ofclaim 18 comprising the steps of:

positioning a reinforcing structure across at least a portion of the cut surface of the proximal portion of the humerus; and

attaching the reinforcing structure to the proximal portion of the humerus.

24. The method ofclaim 18 comprising the step of positioning a support stem in a medullary cavity to support the resected portion.

25. The method ofclaim 24 comprising the step of attaching the resected portion to the support stem.

26. A method for replacing a joint between a first bone structure and a second bone structure, the method comprising:

resecting a convex portion of the first bone structure to form a resected portion having a convex surface, wherein the first bone structure has a cut surface after resecting the convex portion;

positioning the convex surface of the resected portion against the cut surface of the first bone structure; and

driving the resected portion as a single piece into the cut surface of the first bone structure to form a concave articular surface.

27. The method ofclaim 26 comprising the step of processing the cut surface of the first bone structure to form a recess with a shape generally corresponding to the outer convex surface of the resected portion.

28. The method ofclaim 26 comprising the steps of:

locating the outer convex surface of the resected portion on the cut surface of the first bone structure; and

impacting the resected portion into the cut surface of the first bone structure.

29. The method ofclaim 26 comprising locating an interpositional implant in the concave articular surface.

30. The method ofclaim 29 comprising coating the interpositional implant with pyrolytic carbon.

31. The method ofclaim 26 comprising engaging a convex surface of a glenosphere attached to the second bone structure with the concave articular surface of the first bone structure.

32. The method ofclaim 26 wherein the first bone structure and the second bone structure are located in one of a foot and a hand.

33. The method ofclaim 26 comprising replacing the joint by engaging a convex surface on the second bone with the concave articular surface.

34. The method ofclaim 26 comprising replacing the joint by engaging a prosthetic element on the second bone with the concave articular surface.

35. A shoulder prosthesis comprising:

a resected portion of a proximal portion of a humerus comprising an outer convex surface engaged with a cut surface of the humerus and an inner surface processed to comprise a concave articular surface; and

an interpositional implant positioned within the concave articular surface.

36. The shoulder prosthesis ofclaim 35 wherein the inner surface of the resected portion comprises compacting cancellous bone against cortical bone comprising the outer convex surface.

37. The shoulder prosthesis ofclaim 35 wherein the inner surface of the resected portion comprises cortical bone.

38. The shoulder prosthesis ofclaim 35 wherein the resected portion comprises one of a unitary structure or a plurality of pieces.

39. The shoulder prosthesis ofclaim 35 comprising one or more fasteners, bone anchors, or sutures adapted to attach the resected portion to a cut surface of the proximal portion of the humerus.

40. The shoulder prosthesis ofclaim 35 comprising a reinforcing structure located between the outer convex surface of the resected portion and a cut surface of the proximal portion of the humerus.

41. The shoulder prosthesis ofclaim 35 comprising a support stem adapted for insertion into a medullary cavity to support the resected portion.

42. The shoulder prosthesis ofclaim 35 comprising one or more fasteners attaching the resected portion to the support stem.

43. The shoulder prosthesis ofclaim 35 wherein the interpositional implant comprises one of a sphere or a disc.

44. The shoulder prosthesis ofclaim 35 wherein the interpositional implant comprises pyrolytic carbon.

45. A prosthesis comprising:

a resected portion of a bone structure comprising an outer convex surface and an inner surface processed to comprise a concave articular surface; and

an interpositional implant positioned within the concave articular surface.

46. The prosthesis ofclaim 45 wherein the interpositional implant comprises one of a sphere or a disc.

47. The prosthesis ofclaim 45 wherein the interpositional implant is located in one of a shoulder, a hip, an ankle, a foot, and a hand.

48. A prosthesis joint between a first bone structure and a second bone structure comprising:

a resected portion of the first bone structure comprising an outer convex surface engaged with a cut surface of the first bone, and an inner surface of the resected portion comprising a concave articular surface; and

a convex portion of the second bone engaged with the concave articular surface comprising the prosthetic joint.

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