US20220192834A1 - Shoulder arthroplasty system - Google Patents

Abstract

An implant system for total shoulder arthroplasties, hemi shoulder arthroplasties, and “reverse” total shoulder arthroplasties including a humeral stem having an enlarged head portion with interfaces adapted to removably receive various modular interchangeable components, such as articulating liners, spacers, and adapter inserts. The humeral stem functions as a universal platform that may be used in either conventional or “reverse” total shoulder arthroplasties, as well as hemi shoulder arthroplasties, and may remain implanted in place during a revision in which the implant system is converted between the foregoing configurations, for example.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This application claims the benefit under Title 35, U.S.C. § 119(e) of U.S. Provisional Patent Application Ser. No. 60/760,897, entitled SHOULDER ARTHROPLASTY SYSTEM, filed on Jan. 20, 2006 and U.S. Provisional Patent Application Ser. No. 60/805,012, filed on Jun. 16, 2006, entitled SHOULDER ARTHROPLASTY SYSTEM, the entire disclosures of which are expressly incorporated by reference herein.
BACKGROUND OF THEINVENTION1. Field of the Invention
• The present invention relates to surgical implant systems, including implants, instruments, and methods for performing a total shoulder arthroplasty, a hemi shoulder arthroplasty, or a “reverse” total shoulder arthroplasty.
2. Description of the Related Art
• In a healthy shoulder, the proximal humerus is generally ball-shaped, and articulates within a socket formed by the scapula, called the glenoid, to form the shoulder joint. Conventional implant systems for the total replacement of the shoulder joint due to disease or trauma, i.e., a total shoulder arthroplasty, generally replicate the natural anatomy of the shoulder, and typically include a humeral component having a stem which fits within the humeral canal, and an articulating head which articulates within the socket of a glenoid component implanted within the glenoid of the scapula. An implant system for the replacement of only the humeral component of the shoulder joint, i.e., a hemi shoulder arthroplasty, typically includes only a humeral component which articulates within the natural glenoid socket of the scapula.
• Recently, “reverse” type implant systems have been developed in which the conventional ball-and-socket configuration that replicates the natural anatomy of the shoulder is reversed, such that a concave recessed articulating component is provided at the proximal end of the humeral component that articulates against a convex portion of the glenoid component. Such reverse shoulder implant systems are thought to provide an increased range of motion for treatment of glenohumeral arthritis associated with irreparable rotator cuff damage, for example, by moving the center of rotation between the humeral component and the glenoid component to allow the deltoid muscles to exert a greater lever arm on the humerus.
SUMMARY OF THE INVENTION
• The present invention provides an implant system for total shoulder arthroplasties and hemi shoulder arthroplasties, including a humeral stem having an enlarged head portion with interfaces adapted to removably receive various modular interchangeable components, such as articulating liners, spacers, and adapter inserts. The humeral stem functions as a universal platform that may be used in either conventional or “reverse” total shoulder arthroplasties, as well as hemi shoulder arthroplasties, and may remain implanted in place during a revision in which the implant system is converted between the foregoing configurations, for example. The articulating liner articulates against a glenoid component, and may be angled to change the neck angle of the humeral stem from an angle suited for a conventional total arthroplasty or a hemi arthroplasty to an angle suited for a “reverse” total arthroplasty. The spacer may optionally be used to fit between the humeral stem and the articulating liner to provide increased joint tension when needed. The adapter insert is used to provide an interface with a convex articulating component in a hemi arthroplasty application. A glenoid component is also provided which is mountable to the glenoid by a plurality of polyaxial locking screws, and which receives a glenosphere having a smooth, convex and uninterrupted articulating surface against which the articulating liner of the humeral component may articulate.
• In one form thereof, the present invention provides a humeral implant component for use in a total shoulder arthroplasty or a hemi shoulder arthroplasty, including a stem portion extending toward a distal end thereof; a head portion at a proximal end thereof, the head portion including an internal cavity having first engagement structure and a first tapered bore; and a second component received within the internal cavity and including a first stem received within the first tapered bore.
• In another form thereof, the present invention provides a humeral implant component for use in a total shoulder arthroplasty or a hemi shoulder arthroplasty, including a stem portion defining a longitudinal axis; and a head portion having first engagement structure, and a portion which defines a first angle with respect to the longitudinal axis, the first angle between about 35 and about 55 degrees.
• In another form thereof, the present invention provides a humeral implant component for use in a total shoulder arthroplasty or a hemi shoulder arthroplasty, comprising a stem portion defining a longitudinal axis; and a head portion having first engagement structure, and a surface which defines a first angle with respect to the longitudinal axis; and a second component separate from the stem and secured to the first engagement structure, the second component having a second surface defining a second angle between the first surface and the second surface.
• In another form thereof, the present invention provides a humeral implant component for use in a total shoulder arthroplasty or a hemi shoulder arthroplasty, including a stem portion defining a longitudinal axis; and a head portion having first engagement structure; and a second component separate from the stem and secured to the first engagement structure, the second component having a surface defining one of an anteversion angle and a retroversion angle with respect to the longitudinal axis of between about 1 and about 30 degrees.
• In another form thereof, the present invention provides a humeral implant component for use in a total shoulder arthroplasty or a hemi shoulder arthroplasty, including a stem portion extending toward a distal end thereof; and a substantially enlarged head portion at a proximal end thereof, the head portion including a suture groove adjacent the proximal end.
• In another form thereof, the present invention provides a glenoid implant component for use in a total shoulder arthroplasty, including a body having a stem extending from a medial side thereof; at least one hole in the body including a substantially convex seat therein; at least one screw extendable through the hole, the screw including a threaded shank and an at least partially spherical head, the head abuttable against the seat; and a screw retainer movable between a first position wherein the screw head may move polyaxially with respect to the seat and a second position wherein the screw head is retained in a fixed position with respect to the seat.
• In another form thereof, the present invention provides a glenoid implant component for use in a total shoulder arthroplasty, including a base member, including a substantially cup-shaped body having a base wall; and a tapered annular wall extending from a lateral side of the base wall; and an articulating component, including a medial side including a tapered bore receivable onto the tapered annular wall of the base member; and a lateral side defining a substantially smooth, uninterrupted, convex articulating surface.
• In another form thereof, the present invention provides a glenoid component of a reverse shoulder system for implanting on the glenoid of a shoulder, the glenoid component including a glenoid base including a bone engaging first surface and an opposing second surface, the glenoid base including at least one fastener receiving hole extending through the glenoid base from the first surface to the second surface, each fastener receiving hole including a threaded portion proximal the second surface and a substantially spherical portion adjacent the threaded portion and proximal the first surface relative to the threaded portion, the glenoid base having an annular wall extending outwardly from the second surface; a glenosphere having an articulating surface and defining a bore, the annular wall of the glenoid base received within the bore to couple the glenosphere to the glenoid base; a screw having a head and a threaded shank and extending through the at least one fastener receiving hole and insertable into the glenoid, the head being at least partially spherical in shape and configured to be retained in the spherical portion of the at least one fastener receiving hole; and a locking member threadedly engaged with the threaded portion of the fastener receiving hole and abutting the head of the fastener to secure the head of the fastener in the fastener receiving hole.
• In another form thereof, the present invention provides a glenoid component of a shoulder prosthesis system for implanting on the glenoid of a shoulder, the glenoid component including a glenoid base including a bone engaging first surface and an opposing second surface, the glenoid base including at least one fastener receiving hole extending through the glenoid base from the first surface to the second surface, each fastener receiving hole including a threaded portion proximal the second surface and a substantially spherical portion adjacent the threaded portion and proximal the first surface relative to the threaded portion; a screw having a head and a threaded shank extending through the at least one fastener receiving hole and insertable into the glenoid, the head being at least partially spherical in shape and configured to be retained in the spherical portion of the at least one fastener receiving hole; and a locking member threadedly engaged with the threaded portion of the fastener receiving hole, the locking member abutting the head of the screw and restricting movement of the head within the spherical portion of the fastener receiving hole.
• In another form thereof, the present invention provides a reverse shoulder prosthesis system for the repair or replacement of a shoulder joint, the shoulder joint including a humerus and a scapula, the reverse shoulder prosthesis system including a ball assembly mountable on the scapula, the ball assembly including a glenoid base including a bone engaging first surface and an opposing second surface, the glenoid base including at least one fastener receiving hole extending through the glenoid base from the first surface to the second surface, each fastener receiving hole including a threaded portion proximal the second surface and a substantially spherical portion adjacent the threaded portion and proximal the first surface relative to the threaded portion; a glenosphere having an articulating surface and removably mounted to the base proximal the second surface; a screw having a head and a threaded shank extending through the at least one fastener receiving hole and insertable into the scapula, the head being at least partially spherical in shape and configured to be retained in the spherical portion of the at least one fastener receiving hole; and a locking member threadedly engaged with the threaded portion of the fastener receiving hole, the locking member abutting the head of the fastener and restricting movement of the head within the spherical portion of the fastener receiving hole.
• In another form thereof, the present invention provides a glenoid implant component for use in a total shoulder arthroplasty, including a glenoid base including a bone engaging first surface and an opposing second surface, the glenoid base having first engagement structure extending from the second surface; a glenosphere having an articulating surface and second engagement structure configured to engage the first engagement structure; and polyaxial means for anchoring the glenoid component to a glenoid.
BRIEF DESCRIPTION OF THE DRAWINGS
• The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein:
• FIG. 1 is a perspective view of a “reverse” total shoulder arthroplasty implant system according to the present invention, including a humeral component and a glenoid component;
• FIG. 2 is a perspective view of the humeral component of a conventional total shoulder arthroplasty implant system or a hemi shoulder arthroplasty system;
• FIG. 3 is a side view of the humeral stem through a medial/lateral plane, further showing an outline of the humerus;
• FIG. 4 is a perspective view of the proximal end of the humeral stem;
• FIG. 5 is a sectional view through a medial/lateral plane, showing the proximal end of the humeral stem;
• FIG. 6A is a perspective view of the proximal end of an articulating liner;
• FIG. 6B is a perspective view of the distal end of the articulating liner ofFIG. 6A;
• FIG. 7 is an exploded view of the humeral stem and articulating liner;
• FIG. 8A is a partial sectional view through a medial/lateral plane, showing the connection between the humeral stem and an articulating liner;
• FIG. 8B is a partial sectional view through a medial/lateral plane, showing the connection between the humeral stem and the articulating liner ofFIG. 7;
• FIG. 8C is a partial sectional view through a medial/lateral plane, showing the connection between the humeral stem and a second articulating liner;
• FIG. 9A is a perspective view of the proximal end of a spacer;
• FIG. 9B is a perspective view of the distal end of the spacer ofFIG. 9A;
• FIG. 10 is an exploded view of the humeral stem and a spacer;
• FIG. 11 is a partial sectional view through a medial/lateral plane, showing the connection between the humeral stem and the spacer ofFIG. 10, and further showing the connection between the spacer and an articulating liner;
• FIG. 12A is a perspective view of the distal end of an adapter insert;
• FIG. 12B is a perspective view of the proximal end of the adapter insert ofFIG. 12B;
• FIG. 13 is an exploded view of the humeral stem, an adapter insert, and a humeral head;
• FIG. 14 is a partial sectional view through a medial/lateral plane, showing the connection between the humeral stem, adapter insert, and humeral head ofFIG. 13;
• FIG. 15 is a perspective view of the lateral side of a glenoid base;
• FIG. 16 is a perspective view of the medial side of the glenoid base;
• FIG. 17 is a sectional view of the glenoid base;
• FIG. 18 is a perspective view of the medial side of the glenosphere;
• FIG. 19 is a perspective view of a screw;
• FIG. 20 is a first perspective view of a screw lock;
• FIG. 21 is a second perspective view of a screw lock;
• FIG. 22 is a sectional view through the glenoid component, showing connection between the glenoid base, screws, and glenosphere, and further showing a screw and a screw head lock in a locked position on the left and a screw and a screw head lock in an unlocked position on the right;
• FIG. 23 is partial sectional view through an anterior/posterior plane, showing the connection between the humeral stem and an articulating liner according to a further embodiment; and
• FIG. 24 is a partial sectional view through an anterior/posterior plane, showing the connection between the humeral stem and an adapter insert according to a further embodiment.
• Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate exemplary embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention any manner.
DETAILED DESCRIPTION
• As used herein, the following directional definitions apply. Anterior and posterior mean nearer the front or nearer the rear of the body, respectively, proximal and distal mean nearer to or further from the root of a structure, respectively, and medial and lateral mean nearer the sagittal plane or further from the sagittal plane, respectively. The sagittal plane is an imaginary vertical plane through the middle of the body that divides the body into right and left halves.
• Referring toFIG. 1,implant system30afor a “reverse” total shoulder arthroplasty is shown, which generally includes ahumeral component32 adapted to be fitted within a prepared proximal end and canal of a humerus, and aglenoid component34 mounted to a prepared surface of the glenoid via a plurality of screws, wherein thehumeral component32 articulates about theglenoid component34 to replicate the movement of the natural shoulder joint. As described in further detail below,humeral component32 generally includeshumeral stem36 and articulatingliner38 fitted tohumeral stem36 and having a convex articulating surface, andglenoid component34 generally includes aglenoid base40 and aglenosphere42 fitted toglenoid base40 and having a convex articulating surface, wherein articulatingliner38 articulates aboutglenosphere42.
• Referring toFIG. 2,implant system30bfor a conventional total shoulder arthroplasty or a hemi shoulder arthroplasty is shown, which generally includeshumeral component32 that articulates against a conventional glenoid component (not shown) in a conventional total shoulder arthroplasty or which articulates against the intact glenoid of the scapula in a hemi shoulder arthroplasty.Humeral component32 generally includeshumeral stem36, anadapter insert44, and ahumeral head45 fitted toadapter insert44 and having a convex articulating surface.
• Referring toFIGS. 3-5,humeral stem36 is shown, havingproximal end46 and distal end48.Humeral stem36 includeshead portion50 atproximal end46 andstem portion52 extending toward distal end48. In the embodiment shown isFIGS. 3-5,head portion50 andstem portion52 are unitarily formed as a single piece; however,head portion50 andstem portion52 may also be formed of separate components joined to one another.Humeral stem36, as well as the other implant components described herein, may be made of a suitable biocompatible metal, such as titanium, for example, or from other materials as described below.Head portion50 of humeral stem is substantially enlarged with respect to stemportion52, and flares outwardly fromstem portion52 in shape towardsproximal end46 ofhumeral stein36. As may be seen fromFIG. 3, after the proximal end of the humerus is resected and the humeral canal and proximal humeral end are prepared using known instruments (not shown) and methods,stem portion52 is received in the prepared canal of the humerus, andhead portion50 is received within a conically reamed portion of at the proximal end of the resected humerus.
• As shown inFIGS. 4 and 5,head portion50 includes aninternal cavity54 extending into the proximal end thereof, including a first, relativelylarger diameter portion56 with anannular rib58 and a second, relatively smaller diameter portion defining atapered bore60. An annular,outer rim62 is formed about theproximal end46 ofhead portion50 and includes aninstrument seat64 with a central bore which may be used to anchor and locate an impaction instrument (not shown) for impactinghumeral stem36 into a reamed and prepared canal in the humerus. A plurality of suture holes66 are defined inouter rim62 and, as shown inFIGS. 3 and 5, asuture groove68 is disposed beneath and adjacentouter rim62, the functions of which will be described below.
• Humeral stem36 additionally includes, toward theproximal end46 thereof, a plurality of recessed portions, best seen inFIG. 5, in which are disposed pads orcoating portions70 of a highly porous biomaterial useful as a bone substitute and/or cell and tissue receptive material for promotion of bone ingrowth to aid in the osseointegration ofhumeral stem36 within the humerus. An example of such a material is produced using Trabecular Metal™ technology available from Zimmer, Inc., of Warsaw, Ind. Trabecular Metal™ is a trademark of Zimmer Technology, Inc. Such a material may be formed from a reticulated vitreous carbon foam substrate which is infiltrated and coated with a biocompatible metal, such as tantalum, etc., by a chemical vapor deposition (“CVD”) process in the manner disclosed in detail in U.S. Pat. No. 5,282,861, the disclosure of which is incorporated herein by reference. As would be apparent to one skilled in the art, although the embodiments described herein utilize porous tantalum, other metals such as niobium, or alloys of tantalum and niobium with one another or with other metals may also be used.
• Referring toFIGS. 3 and 5,head portion50 ofhumeral stem36 additionally includes ahub section72 of titanium on a lateral side thereof having asuture hole74 through which sutures may be threaded to aid in reducing humeral fractures as needed. Suture holes66 andsuture groove68 ofhead portion50 ofhumeral stem36 may also be used by a surgeon to reconstruct the proximal humerus in the event of humeral fractures, or for the attachment of soft tissue. For example, one or more of suture holes66 may be used to anchor sutures wrapped around bone fragments of the upper humerus usingsuture groove68, for example, to bring the lesser and greater tuberosities into reduction circumferentially abouthumeral stem36, or to attach soft tissue circumferentially abouthumeral stem36. Also, a surgeon may selectively use one, two, three or all of suture holes66 alone or in combination with each other and withsuture groove68 as needed for this purpose. Additionally, the axial clearance beneathouter rim62 ofhumeral stem36 provided bysuture groove68 allows the surgeon to use one or more of suture holes66 for “pull down” sutures to pull bone fragments along the axial direction ofhumeral stem36 for reduction of fractures or for attachment of soft tissue, for example.
• Referring toFIG. 3,outer rim62 at the proximal end ofhead portion50 ofhumeral stem36 defines a substantially flat or planar surface which, as shown, is disposed substantially along a resection cut line L₂-L₂along which a surgeon makes a resection cut to resect the proximal humerus H whenhumeral stem36 is implanted during a total or hemi shoulder arthroplasty. A first neck angle α is defined in a medial/lateral plane between the surface ofouter rim62 along resection cut line L₂-L₂, and the longitudinal axis L₁-L₁ofhumeral stem36. Neck angle α may be as little as about 35, 40, or 45 degrees, and may be as great as about 50 or 55 degrees whenhumeral stem36 is used in a conventional shoulder arthroplasty or in a hemi arthroplasty, as described below. In the embodiment ofFIG. 3 and inFIGS. 8B and 8C discussed below, neck angle α is about 53 degrees. Further, as also described below, an articulating liner may be used to provide a greater neck angle with respect to longitudinal axis L₁-L₁ofhumeral stem36 which is more suited to a “reverse” shoulder arthroplasty.
• Referring toFIGS. 6A and 6B, proximal and distal perspective views respectively, of an articulatingliner38 for fitting tohumeral stem36 are shown, including abody76 which may be formed of a single, integral piece of ultra high molecular weight polyethylene (“UHMWPE”), for example. The proximal end of articulatingliner38 includes a convex articulatingsurface78 for articulating against glenosphere42 (FIG. 1) ofglenoid component34. The distal end of articulatingliner38 includes a plurality ofspring fingers80 spaced therearound and apost82 which may be non-tapered to provide an interference fit within tapered bore60 ofhumeral stem36. Articulatingliner38 further includes a plurality ofrecesses84 disposed about the outer periphery ofbody76 for providing clearance for accessingsuture holes66 ofhumeral stem36 when articulatingliner38 is attached tohumeral stem36 in the manner described below.
• Referring additionally toFIGS. 7 and 8, articulatingliner38 is attachable tohumeral stem36 by using an impaction instrument (not shown) which may include a first portion fitting within the cavity defined by articulatingsurface78 and a second, prong-type portion insertable throughnotch86 in the outer periphery ofbody76 of articulatingliner38 and through the bore ofinstrument seat64 ofhumeral stem36 to rotationally locate articulatingliner38 with respect tohumeral stem36, withpost82 of articulatingliner38 received within tapered bore60 ofhumeral stem36 by an interference fit. Thereafter, articulatingliner38 is impacted intointernal cavity54 ofhumeral stem36 untilspring fingers80 of articulatingliner38 resiliently engage behindannular rib58 ofhumeral stem36 to thereby axiallylock articulating liner38 with respect tohumeral stem36, with rotation of articulatingliner38 with respect tohumeral stem36 prevented by the engagement ofinstrument seat64 ofhumeral stem36 withinnotch86 of articulatingliner38.
• As shown inFIGS. 6A-8C, articulatingliner38 is substantially wedge-shaped, having an annularlower surface83 in abutment withouter rim62 ofhead portion50 ofhumeral stem36 as shown inFIGS. 8B and 8C, and an annularupper surface85 oppositelower surface83. As shown inFIGS. 8B and 8C, lower andupper surfaces83 and85 together define an angle γ therebetween in a medial/lateral plane which may be as small as about 1 or 5 degrees, or may be as large as about 15, 30, or 35 degrees, or may be sized at any one degree increment therebetween, for example. In the embodiment ofFIG. 8B, a first articulatingliner38adefines an angle γ of about 7 degrees and, in the embodiment ofFIG. 8C, a second articulatingliner38bdefines an angle γ of about 12 degrees. Further details of first and second articulatingliners38aand38bare discussed below. When an articulatingliner38aor38bis secured to headportion50 ofhumeral stem36 in the manner described above, theupper surface85 of the articulating liner defines a second neck angle β with respect to longitudinal axis L₁-L₁ofhumeral stem36 or, stated another way, the first neck angle α, between longitudinal axis L₁-L₁ofhumeral stem36 andouter rim62 along resection cut line L₂-L₂, and the angle γ of articulatingliner38 combine to define second neck angle β. As with first neck angle α and angle γ of articulatingliner38, second neck angle β is in a medial/lateral plane. Second neck angle β may be as small as about 55 or 60 degrees, or may be as large as about 65 or 70 degrees whenhumeral stem36 is configured for a “reverse” shoulder arthroplasty, and the articulatingliner38 may be selected from a plurality of articulatingliners38 having varying angles γ to provide proper stability for the shoulder joint. In the embodiment ofFIG. 8B, second neck angle β is about 60 degrees and in the embodiment ofFIG. 8C second neck angle β is about 65 degrees.
• Articulatingliner38 may be selected by a surgeon from a plurality of differently-sized articulating liners, having varying size diameters and heights, for example, to provide a properly sized articulating liner for a given patient anatomy and/or joint reconstruction need. Additionally, a plurality of trial or provisional articulating liners (not shown) may be provided with the present implant system, which lackspring fingers80 and/or post82 but otherwise are substantially identical to the implanted articulatingliner38. In this manner, a surgeon may use such provisional articulating liners during the arthroplasty procedure to determine the correct size of articulating liner to be implanted, followed by selecting the desired articulating liner and securing same tohumeral stem36 in the manner described above.
• Referring toFIGS. 8B and 8C, two differently-sized articulatingliners38aand38bare shown, which are structurally identical except for the diameter of articulatingsurfaces78aand78bthereof. In one embodiment, articulatingliner38ahas an articulating surface78awith a diameter D₁of 36 mm, and articulatingliner38bhas an articulatingsurface78bwith a diameter D₂of 40 mm. However, the diameters of the articulatingliners38 may be as small as about 30 mm, 32 mm, or 34 mm, or may be as large about 50 mm, 55 mm, or 60 mm, or may be sized at any one degree increment therebetween, for example. Articulatingliner38amay typically be used in most patients; however, articulatingliner38bmay be used in relatively larger patients, or in other cases where a greater diameter articulating surface may be desired such as, for example to provide greater joint stability. Advantageously, because the above-described structure by which articulatingliners38aand38bare secured to headportion50 ofhumeral stem36 is identical, a surgeon may intra-operatively select an appropriate articulating liner from articulatingliner38a, articulatingliner38b, or an articulating liner having a differently sized or differently dimensioned articulating surface (not shown) based on the anatomical needs of a particular patient. Thus, a series of articulating liners may be provided, having varying articulating surface diameters or other dimensions, which are compatible withhumeral stem36.
• Optionally, spacers90 (FIGS. 9A-11) of various size, described below, may be used to provide increased tension on the shoulder joint when needed in the event that the height of articulatingliner38 is not sufficient to provide such tension. Referring toFIGS. 9A and 9B, proximal and distal perspective views, respectively, of aspacer90 are shown, including abody92 which may be formed of titanium, for example. The proximal end ofspacer90 includesinternal cavity94 having anannular rib96 and abore98 which dimensionally replicate theinternal cavity54 ofhumeral stem36 and in particular, theannular rib58 and bore60 ofhumeral stem36, described above. Additionally,spacer90 includesinstrument seat100 replicatinginstrument seat64 ofhumeral stem36, described above. The distal end ofspacer90 includes taperedstem102 for lockably fitting within tapered bore60 ofhumeral stem36.Body92 ofspacer90 includes a plurality ofrecesses104 disposed about an outer periphery thereof for providing clearance for accessingsuture holes66 ofhumeral stem36 whenspacer90 is attached tohumeral stem36 in the manner described below.
• In use, referring additionally toFIGS. 10 and 11,spacer90 may be fitted tohumeral stem36 using a suitable instrument (not shown) in substantially the same manner as articulatingliner38 described above, withtapered stem102 ofspacer90 providing a tapered lock fit within tapered bore60 ofhumeral stem36, and with relative rotation betweenspacer90 andhumeral stem36 prevented by engagement ofinstrument seat64 ofhumeral stem36 within notch106 (FIG. 9B) ofspacer90 disposed oppositeseat100 ofspacer90. Thereafter, a selected articulatingliner38 may be attached withininternal cavity94 ofspacer90 in the same manner as that described above with respect to the attachment of articulatingliner38 tohumeral stem36, namely, by engagingspring fingers80 of articulatingliner38 withannular rib96 ofspacer90 and receipt ofpost82 of articulatingliner38 withinbore98 ofspacer90.Spacer90 also includes a threadedcentral bore108 that may be used for threading receipt of a threaded end of a retrieval instrument (not shown) used to removespacer90 fromhumeral stem36 whereby, upon threading of the threaded end of the retrieval instrument through threadedbore108, the threaded end will bottom out against the bottom of tapered bore60 ofhumeral stem36 to disengagespacer90 fromhumeral stem36.
• Referring toFIGS. 12A and 12B, distal and proximal views ofadapter insert44 are shown, which may be used withhumeral stem36 to provide an interface withhumeral head45 to configurehumeral stem36 for use in a conventional total shoulder arthroplasty or a hemi shoulder arthroplasty. The proximal end ofadapter insert44 includes a firsttapered stem110 and the distal end ofadapter insert44 includes a secondtapered stem112, with acentral bore114 extending therethrough. Referring additionally toFIGS. 13 and 14, when the distal end ofadapter insert44 is received withininternal cavity54 ofhumeral stem36, secondtapered stem112 ofadapter insert44 is lockingly fittable within tapered bore60 ofhumeral stem36. Thereafter,humeral head45, which includes a distaltapered bore116 and proximal convex articulatingsurface118 may be fitted onto firsttapered stem110 ofadapter insert44 to complete the humeral assembly. In use, as described above, convex articulatingsurface118 ofhumeral head45 articulates against a conventional glenoid component (not shown) in a conventional total shoulder arthroplasty, or articulates against the intact glenoid of the scapula in a hemi shoulder arthroplasty.Adapter insert44 additionally includes thread120 (FIG. 12A) withincentral bore114 to enableadapter insert44 to be removed fromhumeral stem36 using a threaded retrieval instrument (not shown) analogous to the manner described above with respect to the removal ofspacer90 fromhumeral stem36.
• As discussed below, the articulating liners and the adapter inserts of the present shoulder implant system may also include an anteversion or retroversion feature. Referring toFIGS. 23 and 24, further embodiments of an articulating liner and an adapter insert are shown, which are each angled in an anterior/posterior plane with respect to the longitudinal axis L₁-L₁ofhumeral stem36 to provide anteversion or retroversion.
• Referring toFIG. 23, an articulatingliner38cis shown attached tohumeral stem36 which, except as described below, is identical to articulatingliner38 described above.Body76 of articulatingliner38cincludes a concave articulating surface78cwhich is oriented at an angle Δ in an anterior/posterior plane with respect to longitudinal axis L₁-L₁ofhumeral stem36. Specifically, a line L₃-L₃, which is perpendicular to articulating surface78cand passes through the center thereof, defines angle Δ with respect to longitudinal axis L₁-L₁ofhumeral stein36. Angle Δ may define an anterior-facing orientation of articulating surface78cfor anteversion or, as shown inFIG. 23, angle Δ may define a posterior-facing orientation of articulating surface78cfor retroversion. Angle Δ may be as small as about 1, 5, or 10 degrees, or may as large as about 20, 25, or 30 degrees, or may be sized at any one degree increment therebetween, for example. In the embodiment ofFIG. 23, angle Δ is about 20 degrees. Additionally, as shown inFIG. 23, the articulatingliners38 disclosed herein may include both the foregoing anteversion or retroversion angle Δ in an anterior/posterior plane with respect to longitudinal axis L₁-L₁ofhumeral stem36, as well as the above-described angle γ in a medial/lateral plane with respect to the longitudinal axis L₁-L₁ofhumeral stem36. In this manner, articulatingliner38ccan be used to provide anteversion or retroversion in a “reverse” total shoulder arthroplasty.
• Referring toFIG. 24, adapter insert44ais shown attached tohumeral stem36 which, except as described below, is identical to adapter insert44 described above. Adapter insert44aincludes an angled body portion111 which positions first taperedstem110 of adapter insert44aat an angle Δ in an anterior/posterior plane with respect to longitudinal axis L₁-L₁ofhumeral stem36. Specifically, a line L₃-L₃, which extends along the longitudinal axis of adapter insert44aandtapered stem110, defines angle Δ with respect to longitudinal axis L₁-L₁ofhumeral stem36. Angle Δ may define an anterior-facing orientation of firsttapered stem110 for anteversion or, as shown inFIG. 24, angle Δ may define a posterior-facing orientation of firsttapered stem110 for retroversion. Angle Δ may be as small as about 1, 5, or 10 degrees, or may as large as about 20, 25, or 30 degrees, or may be sized at any one degree increment therebetween, for example. In the embodiment ofFIG. 23, angle Δ is about 20 degrees.Humeral head45, having convex articulatingsurface118, is mounted to firsttapered stem110 of adapter insert44ain the manner described above, and is oriented according to the anteversion or retroversion angle defined by adapter insert44a. Additionally, similar to the articulatingliners38 disclosed herein, adapter insert44amay include both the foregoing anteversion or retroversion angle Δ in an anterior/posterior plane with respect to longitudinal axis L₁-L₁ofhumeral stem36, as well as an angle in a medial/lateral plane with respect to the longitudinal axis L₁-L₁ofhumeral stem36. In this manner, adapter insert44acan be used to provide anteversion or retroversion in a conventional total shoulder arthroplasty or in a hemi shoulder arthroplasty.
• Advantageously,humeral stem36 provides a humeral component which serves as a universal humeral implant platform that may be used with the various modular components in the manner described above to configurehumeral stem36 for use in a “reverse” total shoulder arthroplasty, a conventional total shoulder arthroplasty, or a hemi shoulder arthroplasty. Thus, once thehumeral stem36 is implanted within the proximal humerus as shown inFIG. 3, thehumeral stem36 may be configured for a “reverse” total shoulder arthroplasty as shown inFIGS. 1 and 6A-11, or a conventional total shoulder arthroplasty or hemi shoulder arthroplasty as shown inFIGS. 2 and 12A-14 according to patient needs by using the components described above.
• Also, once implanted,humeral stem36 may remain implanted throughout any necessary revision procedures, allowing a surgeon to perform any revisions as needed by replacing one more of the various modular components described above without the need to replacehumeral stem36 itself. For example, if a patient initially has a hemi shoulder arthroplasty and later is in need of a revision to receive a “reverse” total shoulder arthroplasty,humeral head45 is removed, followed byadapter insert44. Thereafter, an articulatingliner38 and optionally, aspacer90, are attached tohumeral stem36 in the manner described above without the need to removehumeral stem36 from the patient's humerus. A similar procedure may be used to convert a conventional total shoulder arthroplasty to a “reverse” total shoulder arthroplasty.
• One particular advantage ofhumeral stem36 is that the proximal surface thereof lies substantially along the resection cut line L₂-L₂of the resected humerus as discussed above. Thus, the various modular components disclosed herein may be attached, removed, and/or replaced onto the implantedhumeral stem36 above the resection cut line L₂-L₂without the need for removing bone around the proximal humerus H and/or replacing or modifying the location of the implantedhumeral stem36 in the humerus H.
• Referring toFIGS. 15-22, glenoid component34 (FIG. 22) is shown, which generally includes aglenoid base40, shown inFIGS. 15-17 and 22, and glenosphere42, shown inFIGS. 18 and 22. Referring toFIGS. 15-17,glenoid base40 includes abody130 which may be made of a suitable biocompatible metal such as titanium, for example, and includes stem portion132 (FIG. 17) projecting from a medial side thereof, and a taperedannular wall134 projecting from a lateral side thereof. The medial side ofbody130 ofglenoid base40, includingstem portion132, may include a pad orcoating portion135 of the highly porous biomaterial described above, produced using Trabecular Metal™ technology available from Zimmer, Inc., of Warsaw, Ind., to promote bone ingrowth from the glenoid into and aroundglenoid base40 to thereby osseointegrateglenoid base40 with the glenoid. Typically, the glenoid is prepared for attachment ofglenoid component34 by preparing a bore in the glenoid for receipt ofstem portion132 ofglenoid body130, and by reaming the glenoid with a reamer (not shown) to prepare a substantially flat, planar surface on the glenoid to which the substantially flat, planar medial side ofbody130 may be fitted, as described below.
• Body130 ofglenoid base40 includes a pair ofbores136 therethrough which, as best shown inFIG. 17, include first, threadedportions138 andsecond portions140 which are tapered to open outwardly toward the medial side ofglenoid base40.Bores136 additionally includescrew head seats142 located between first andsecond portions138 and140 ofbores136. As shown,screw head seats142 have an at least partially spherical shape, but may also have an angled or tapered profile. To secureglenoid base40 to the glenoid, a pair ofpolyaxial screws144 are provided, shown inFIG. 19, each including a substantiallyspherical head146 with tool engagement structure, such as apolygonal fitting148, and a threadedshank150. Screw locks152, shown inFIGS. 20 and 21, are also provided which, as described below, cooperate with threadedportions138 ofbores136 and withheads146 ofscrews144 to lock the positions ofscrews144. Eachscrew lock152 generally includes anexternal thread154, a semi-sphericalconcave seat156, and instrument engagement structure such as apolygonal fitting158.
• Referring toFIG. 22,glenoid base40 is shown with ascrew144 and screwhead lock152 in a locked position on the left and ascrew144 and screwhead lock152 in an unlocked position on the right. To secureglenoid base40 to the prepared glenoid, eachscrew144 is inserted using a suitable instrument (not shown) through arespective bore136 inbody130 and is threaded into a pre-tapped bore in the glenoid. Taperedsecond portions140 ofbores136 accommodate polyaxial positioning ofscrews144 up to an angle of 30° from the longitudinal axis ofglenoid base40 as defined alongstem portion132 thereof. Advantageously, the ability ofglenoid base40 to accommodate polyaxial positioning ofscrews144 allows the surgeon to determine optimum angles ofscrews144 needed to conform to the anatomy of the patient and/or to most effectively take advantage of available bone stock to anchorglenoid base40 to the glenoid. Thereafter, referring to the left ofFIG. 22, screw locks152 are threaded into threadedfirst portions138 ofbores136 using a suitable instrument (not shown) to firmly engageseats156 of screw head locks152 againstheads146 ofscrews144, thereby firmly pressing screw heads146 againstseats142 withinbores136 to locking screw heads146 in a selected fixed position and in turn to fix the positions ofscrews144 with respect toglenoid base40.
• Advantageously, as may be seen inFIGS. 17 and 22, becausebody130 ofglenoid base40 includes taperedsecond portions140 ofbores136 to accommodate polyaxial positioning ofscrews144, withscrew seats142 recessed into the medial side ofbody130 ofglenoid base40,glenoid base40 may include a substantially planarmedial side160, with taperedsecond portions140 ofbores136 accommodating polyaxial positioning ofscrews144. The planarmedial side160 ofglenoid base40 allowsglenoid base40 to be seated against a planar surface of the glenoid which may be prepared with a planar reamer (not shown), and eliminates the need for boss portions or other protuberances projecting from the medial side ofglenoid base40 to accommodate polyaxial positioning ofscrews144, which would require additional glenoid preparation steps to accommodate.
• Referring toFIGS. 18 and 22, glenosphere42 generally includes a medial side having a taperedinterior bore162 extending therein, which may be aligned with a longitudinal axis ofglenosphere42 or may be offset with respect to the longitudinal axis ofglenosphere42.Glenosphere42 additionally includes a lateral side having a convex articulatingsurface164.Glenosphere42 may be provided in a variety of different sizes, such as with varying diameters, varying heights, and varying offsets forinternal bore162 to enable a surgeon to select an optimal glenosphere needed for the anatomy of a particular patient. The glenosphere is fitted ontoglenoid base40 by lockingly fitting tapered bore162 ofglenosphere42 onto the cooperatively taperedannular wall134 ofglenoid base40. Advantageously, the foregoing attachment betweenbore162 ofglenosphere42 andannular wall134 ofglenoid base40 allowsglenosphere42 to have a substantially smooth, uninterrupted articulatingsurface164 which lacks an opening therein for receipt of a fastener, for example.
• While this invention has been described as having a preferred design, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

Claims (1)

What is claimed is:

1. A humeral implant component for use in a total shoulder arthroplasty or a hemi shoulder arthroplasty, comprising:

a stem portion extending toward a distal end thereof;

a head portion at a proximal end thereof, said head portion including an internal cavity having first engagement structure and a first tapered bore; and

a second component received within said internal cavity and including a first stem received within said first tapered bore.

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