CA2223790A1

CA2223790A1 - Modular acetabular reinforcement system

Info

Publication number: CA2223790A1
Application number: CA002223790A
Authority: CA
Inventors: Alan Cornell; Ian Revie; Anthony P. Sanders; Allan E. Gross
Original assignee: Johnson & Johnson Professional, Inc.; Alan Cornell; Ian Revie; Anthony P. Sanders; Allan E. Gross
Current assignee: Johnson and Johnson Professional Inc
Priority date: 1996-12-07
Filing date: 1997-12-04
Publication date: 1998-06-07
Also published as: DE69729265T2; DE69729265D1; US5871548A; EP0846453A3; EP0846453B1; EP0846453A2; JPH10201779A

Abstract

A modular acetabular reinforcement system includes a substantially cup-shaped reinforcement body having a peripheral flange portion. One or more fixation wings, of various sizes and shapes, are selectively and separately attachable to the flange portion of the reinforcement body. The system is mountable within the acetabulum of a patient to reinforce the acetabulum and to serve as a platform for other prosthesis components such as an acetabular shell.

Description

MODULAR ACETABULARRE~NFORCEMENTSYSTEM

BACKGROUND OFTHEn~nON

The invention relates to i...p~ .hlP prostheses, and more particularly to col-lpone~ s of hip joint prosth~osP~s The hip joint is a ball-and-socket type joint in which the ball-shaped femoral head is eng~ged with and articulates with a cup-shaped socket knGwn as the acetabulum. Injury and/or disease may damage the hip joint to the extent that it must be replaced by or allgl--f nt~d with a prosthetic joint. Deterioration of the acetabulum, and particularly the car~lage within the acetabulum, requires that a prosthetic acetabular shell be mounted within a l.lt;p~ed area of the acetabulum. The acetabular .hell receives and articulates with a prosthetic femoral head which is in~llçd on a proximal portion of a patient's femur.

In some instances, degenerative bone conditions deteriorate the acetabulum, and particularly its medial wall, to the extent that the acetabulum does not have the integrity to serve as a ,noul.Ling platform for a prosthetic acetabular shell. This con~1ition l~;quires a reinforcement prosthesis which is imp]~ntçd within the ace;~ lum before the acetabular cup, and at least a portion of which receives the acetabular cup. Such a reinfolcel.lent body, somç~imPs known as a protrusio cage, inchldçs a main body th~t is at least partially cup-shaped and which includes two or more integral radially PYtPntling flanges. The protrusio cage is first stabilized within the acetabulum using bone cement or bone screws. Thereafter, the flanges are joined to the ilium, ischium and pubis to fu~ r secure the cage and to distribute forces away from the medial wall of the acetabulum. An eY~npl~ry protrusio cage 2 is further described by Oh et al., Clin. Orthopaedics and Related Research, No. 162, pp.

3 175-184 (1982) and by SCh~s7~r et al., Arch. Orthop. Traum. Surg., Vol. 103, No. 1, pp.

4 5-12 (1984). U.S. Patent Nos. 4,437,193 and 4,623,352 also describe eY~mrl~ry pfOlluS;O
cages.

6 While known ~lOt~u~iO cages can be useful, they are often ~lifficult to install in an 7 ideal manner due to natural anatomical differences among patients as well as anatomical 8 differences resulting from different disease and/or injury con-litit~n~. Rec~nse of these 9 ~n~ol~ir~l diff. .~,lces, the fi~ced flanges of known protrusio cages must be manipulated and/or altered, during surgery, to properly install the protrusio cage. Even with such 11 manipulation and alteration, the protrusio cages still may not be optimally impl~nt~d within 12 some p~tient~

13 Accordingly, there is need for protrusio cages, or similar acetabular reinfor~m~nt 14 bodies, that can be more easily installed by surgeons during hip arthroplasty procedures to accornmod?t~ the varying analo",ies of p~ti~nt~

16 BRIEF SUMMARY ~F THE INVE~IION

17 The invention provides a modular reinforcement system which can be used to 18 ~ug~ t structural we~kn~Ps of the acetabulum caused by degencldli~e conditions. The 19 reinforcement system serves as a pldl~llll upon which known hip prosthesis components, such as an acetabular shell, can be mounted.

21 The modular acetabular r~inforcement system comprises a reinforcement body, which 22 can be s~bst~nti~lly cup-sl-aped. having dome and rim ends and at least one peripheral flange 23 portion ext~ntling along at least a portion of the perimeter of the rim end. The dome end is 24 inserted within the acetabulum while the peripheral flange of the rim end mounts adjacent to the acetabular lip. The system further comprises at least one att~rh~hle fixation wing that is 26 separately ~ttAch~hle to the rein~r~ement body. Each fixation wing has a first end that is ~u~
T~: ~617)a~0D
F~: (617) ~7}s7a ~ tt~~h~ble to the peripheral flange portion of the reinforcement body and an opposed, second 2 end which can be affixed to bone adjacent the acetabulum. The fixation wing in~1u~l~ps at 3 least one bone fixation hole disposed therein that can accommodate bone screws or the like to 4 assist in securing the reillror~",ent body to portions of the patient's pelvic bone. The S re~nfor~...cn~ body itself may include one or more holes disposed therein to assist in 6 ~fl~sing, or partially ~ffi~ing, the reinforcement body to the acetabulum. Optionally, bone 7 screws may be inserted through the holes in the reinforcement body to assist in mounting or 8 stabilizing the reinforcement body within the acetabulum. In some in~t~nc~s the use of bone 9 screws can be avoided and initial fixation of the reinforcement body within the acetabulum 10 can be accompli~h~d using bone cement.

11 The flange portion of the reinforcement body may include one or more fiY~tion holes 12 that can coo~,ate with similar fixation holes disposed on the first end of the fi~tion wing so 13 that screws, rivets, or other fixation elPment~ can selectively join one or mor~ fi-~ti()n wings 14 to the l~;nÇor~"-ent body.

The system may include one or more fixation wings, and the fixation wings can be16 provided in difr~ nt sizes and shapes.

17 The reinror~."ent system of the invention can be utilized by first pl~aling the 18 acetabulum and then inserting the reinforcement body within the acetabulum in a~
19 appropriate position and oriPnt~tiQn as required by the patient's ana~o",y. The initial l~
20 or stabili7~tinn of the reinror~."ent body within the acetabulum can be err~ted using bone 21 screws or bone cem~nt The surgeon then selects from among a variety of dirr~le.~tly si_ed 22 and shaped fi~tion wings, depending on the anato"-y and bone con~itinn of a given ~atient, 23 so thal one or more suitable fixation wings is SPl~P~t~P~. The first end thereof is ~tt~ChpA to 24 the flange portion of the reinforcement body through an a~ropliate fixation technique. .~nv 25 ne~ss~.y manipulation or alteration of the fixation wing can be effected, and the second end 26 of the fixation wing is then affixed to bone within the pelvic area of the patient. In most 27 inct~nCPS the second ends of the fixation wings are ~tt~hP~ to the ilium and i~chium and the 28 pubi~ ~ f the patient in order to properly secure the reinforcement body and to create t~U~, UcClE~ ~ FISH. 1 T~e: ~61n~m F~: (617) n3 n~

desirable force transfer away from the medial wall of the acetabulum. It is understood that 2 the steps noted above are intended to be exemplary and that surgeons may well deviate from 3 the l~r~lule noted above. For example, it may be desirable to assemble the fixation wings 4 prior to placing the reinforcement body.

6 Figure 1 is a ~~ e view of an acetabulum reinforcement system constructed 7 according to the present invention.

9 Figure 2 is an exploded view of the modular acetabular reinfo,~;e."ent system of Figure 1.

11 Figure 3 is a ~ec~i~e view of an altern~ve embo iimpnt of a modular acetabular 12 reinfor~ment system according to the present invention.

13 Figures 4A - 4D illl~t~tP various designs of fixation wings useful with the system of 14 the present invention.
16 Figure S is a s~P~tion~l view of an acetabulum having mounted therein a re.l~fof~,.,cnt 17 system acco~ling to the present invention.

18 Figure 6 is a front view of a modular acetabular system of the invention mounted 19 within the acetabulum.

Figure 7 illustrates an exemplary rivet connP~tion that .s u~li7ed to join a fixation 21 wing to the reinforcement body.

N~rl~. UdlE~I ~ F1511, II~P
T~ 617) ~2000 F~b: (617) g~97q Referring to Figures 1-3, the acetabular reinfo,~m. nt system 10 of the invention 2 includes a reinforcement body 12, which is suhst~nti~lly cup-shaped. The body 12 has dome 3 14 and Am 16 ends, and a p. li~h~l flange portion 18 is formed as a part of the rim end.
4 One or more fixation wings 20 are selectively and separately ~tt~ch~hle to flange portion 18.
S In one embo~limpnt~ fixation elPment~ 22, such as screws or Avets and the like, can be used 6 to secure the fixation wings 20 to the flange portion 18.

7 The reinforcement body, as ilhlstr~tP~ in Figures 1-3. may have an open ,dome end 8 14, ~ senlcd by apical hole 24. Alternatively, as illustrated in Figure 5, the dome end 14 9 may be closed to form a roof-like structure 13 for the reinfo.ce",h~t body. The rim end 16 must be open and should be of suitable dimensions to receive an acetabular shell (not shown) 11 of known slluclull .

12 The structure iidewall 26 of reinforcement body 12 preferably is at least partially 13 dome-shaped such tha. the nomin~ tr~ (D,) of the opening at Am end 16 is greater than 14 the nominal ~ meter (D2) of the opening at the dome end 14. Structural sidewalls 26 preferably include coullt~rsinks 28 which can accommo~te bone screws or, ~l~r ~ ~~hl;vely, 16 encourage bone-growth. Flange 18 can be forrned in a continuous manner (not illustrat~) 17 about the perim~ter of the rim end of the reinforcement body 12. As illllstrated in Figures 1-18 3, flange 18 preferably is discontinuous. Figures 1 and 2 illustrate a reinforcement body in 19 which flange 18 inrludes supeAor-lateral flange 30 and a smaller, inferior-medial flange 32.
Figure 3 ill,.,l.~.t~s a reinforcemellt body in which flange 18 inçlu-les sup~ri-r-lateral flange 21 30 and an inferior-medial flange tab 34. Preferably, the flange 18 inchldes holes 36 that can 22 assist in ~ffi~ing the fixation wings to the reinforcement body.

23 The fixation wings 20 include a first end 38 and an opposed second end 40. Fixation 24 holes 42 preferably are formed on the first end 38 of the fixation wings 20. Holes 42 should be of a size and shape such that they ~re suitable to cooperate with holes 36 disposed in 26 flange portion 18. Fixation elements 22, such as screws, rivets, and the like, can be inserted 27 through holes 36 and 42 to selectively join fixation wings 20 to the reinfor~l.,ent body 12.

T~:: ~617)~100 F . ~ (617) 97~141 The body portion 44 of the fixation wing preferably includes one or more 2 coun~lai,lks 29 that can be used to seat bone screws 46 to secure the fixation wings 20 to 3 portions of bones within the pelvis of a patient.

4 A variety of fixation techniques can be used to selectively join fixation wings 20 to S reillforcel,lent body 12. For eY~mpl~P, the fixation elemlontc 22 can be such that they include 6 a combination of nuts and bolts that firmly and selectively secure the fixation wings to the 7 reinfor~.l.ent body. ~lt~rn~tively, a crimping tool (not shown) can be used to deform the 8 intPrf~cin~ portions of the fixation wings 20 and the flange portion 18 in order to create an 9 interl~l~jng m~.h~nit-~l engagement of these e]emPnt~

Figure 2 illllstr~t~s an embodiment in which the fixation PlPmPntC 22 are rivets 23.
11 Rivet 23a is an lm~spmhled~ lln~ch~t~d rivet inclll-ling mandrel portion 25. Adjacent rivet 17 23a is rivet 23b which is ~ccPmh!~d within the fixation wing, but which is not ~ t~d.
13 Figure 2 also illustrates rivet 23c which is assembled and actl~tçd within a hole 42 of 14 fi~ation w ng 20. Rivet 23d is an eY~mrlP of an ach~ated rivet eYplo/W from hole 42.

Figure 7 illustrates a rivet conn~tion in which rivet components 48 and 50 c~Joperate 16 to secure the flange 18 and the fixation wing 20 to each other. Although Figures 1 ar.d 2 17 illustrate the use of two fixation elPmentc to secure each fixation wing 20 to flange 18, it is 18 ~nderstood that it may be desirable to use only one fixation element to enable pivotal 19 movernent of the fixation wing with respect to the reinforcement body to accommodate 20 anatolllical differences among p~tiPnt~. ~lt~ tively, more than two fixation elP-m~nt~ can 21 be used to secure a single fixation wing to flange 18.

22 Figures 4A-4D illustrate various shapes in which fixation wing 20 can be created.
23 Figure 4A illustrates a subst~nti~lly rectangular fixation wing 52, and 4B illustrates a 24 subst~nti~lly wedge shaped fixation wing 54. Figure 4C illustrates an L-shaped fixation wing 25 56 in which the first end 38 is part of the body 53 of the fixation wing and the second end 40 26 is forrned on the leg 55 of the L-shaped device. Figure 4D illustrates a T-shaped fixation 27 wing 58 in ~nich the first end 38 is part of the leg 57 of the T-shaped device and the second Td9~: ~61n ~m F~ile: (~Inn~n~ -6-end 40 is part of the head 59 of the T-shaped device. It is understood that vdrious ~ ive 2 designs can be utilized for fixation wings. Figures 1 and 2 illustrate a reverse wedge design 3 for a fixation wing in which first end 38 is slightly wider than second end 40.

4 Figure 3 illustrates another embodiment of the reinforcement system 10 of the invention. As shown, reinforcement body 12 includes a peripheral nange 30 and a hook 6 flange 34. P~ ;l h~ dl flange 30 and hook flange 34 each include holes 36. In ~diti~n, the 7 structural sidewalls 26 of the reinforcement body 12 include co~n~te.~inks 26. Figure 3 also 8 illuslldtcs the joinder of fixation wings 54 and 58 to p~ h~al flange 30. Although not 9 illustrated, it is undastood that if desired, an additional fixation wing, of a desired size and shape, may be affixed to hook flange tab 34.

11 As illustrated in Figure 5, a reinforcement body 12, having a closed dome end 13 is 12 mounted within the acetabulum 15. A bone screw 46 irlitially secures the leinror~",ent body 13 within the acetabulum. Fixation wings 20 are joined to the flange portion 18 of the 14 Qil~fol.;G",cnt body and are affixed to the ilium 60 and pubis 62 throug~ bone screws 46.

Figure 6 further illustrates a reinforcement body 12 mounted within the acetabulum.
16 As shown, fLsation wing 54 is affixed to peli~hcral flange 30, and bone screws 46 secure the 17 p~ he.~l flange to the ilium 60. As illustrated fixation wing 56 is secured to hook flange 18 34 and fu~ation wing 56 is secured to the pubis 62 by bone sc.ew 46.

1$~ The ~infol~",cnt system of the invention p~fel~bly is made of a biooo.. ~ ;hlP
mP.t~llic m~t~ri~l. The reinrol~."ent body 12, fixation wings 20 and fxation elP- .lf ~t~ 22 21 preferably are made of a soft, malleable metal that enables a s~lrgeon to manipulate these 22 components during surgery, if neces~ry, to properly conform them to a patient's ana~",y.
23 One exe."pl~y m~t~Pn~l includes commercially pure titanium metal Alternatively, fixation 24 elements 22, like bone screws 46 and rivets 23, can be made of known "iologically comp~tible metals or metal alloys including titanium alloys, cobalt-chlu,,,iu,l, alloys and 26 st~inlp~ steel.

T~: (617) a9-DOO
F~i~b~

1The use of the reinforcement system of the invention will be readily ~I,~ent to one 2 having ordinary skill in the art. Briefly, however, the patient's acetabulum is prepared in a 3 known manner, and the reinforcement body 12 is position~A therein in a desired o. ;e~ n 4 The reinforcement body can be initially secured or stabilized within the acetabulum through S the use of one or more bone screws or bone cement. If n~e~C~, y, the flange portion, as 6 well as other portions of reinforcement body 12 can be manipulated (i.e., deformed) to 7 achieve a desired fit or position with respect to the patient's anatomy. The surgeon can then 8 select the applu~iate size and shape of fixation wing to be used, as well as the tlimPn~ion~ of 9 the fixation wing. The fixation wings can then be secured to the reinforcement body in 10 desired ~ tionc of flange portion 18 through the ~pp~ idte f~t~ning technique. Any 11 manipulation of the fiY~tion wings to achieve applupliate fit can be accompli~h~d by 12 deforming or altering (i.e., cutting) the fixation wings, and the fixation wings are then 13 secured to desired areas of the pelvis through one or more bone screws.

14The fixation wings can vary in size as required by a patient's anatomy. Generally, 15the fi~ation wings have a length of about 20 to 70 mm and a width of about 10 to 70 mm.
16 One of or~inal~ skill in the art can readily determine the applu~lidle ~lim~n~ nc to be 17 ~ lmed by the fixation wings.

18It will be app~cnl to those of ordinaly skill in the art that an illlpOl~t advantage of 19 the invention is that the reinforc~ment system provides added flexibility to a surgeon. The 20 surgeon can select from among a vari~ of fixation wings, having different sizes and shapes, 21 and mount these fixation wings at an ap~lul,liate location on the reinÇulce.llent body.
22 Variations in the surgical technique used to implant the reinfolcel-lent body of the invention 23 are ~nti-~ip~t~d as well. It is unders~ood that various mo lifi~tions may be made to the 24 invention without departing from the scope thereof. All references cited herein are expressly 25 incol~l~cd by reference in their entirety.

T~: (6-n 439-DW
F.~-: ~617) V~Y7~ -8-

Claims

1. A modular acetabular reinforcement system, comprising:

a reinforcement body having dome and rim ends, and at least one peripheral flange portion extending along at least a portion of a perimeter of the distal end;

at least one separately attachable fixation wing, each of the at least one fixcation wings having a first end attachable to the reinforcement body and an opposed, second end; and at least one bone fixation hole disposed in the fixation wing.

2. The system of claim 1 wherein the reinforcement body further comprises at least one periphal flange portion extending along at least a portion of a perimeter of the rim end.

3. The system of claim 2 wherein the reinforcement body includes an outer, bone-engaging surface and an opposed inner surface, the outer bone-engaging surface being adapted to mount within the natural acetabulum of a patient.

4. The system of claim 3 wherein the rim and dome ends are each open.

5. The system of claim 4 wherein the rim end has a diameter that is greater than the dome end.

6. The system of claim 1 wherein at least one bone fixation hole is disposed in the reinforcement body.

7. The system of claim 6 wherein the bone fixation holes are screw holes.

8. The system of claim 7 further comprising one or more fixation elements effective to affix the reinforcement body within the acetabulum.

9. The system of claim 2 wherein at least one flange fixation hole is disposed in the flange portion.

10. The system of claim 9 further comprising one or more fixation elements that cooperate with the flange fixation holes to selectively join each fixation wing to the flange portion of the reinforcement body.

11. The system of claim 1 wherein a plurality of bone fixation holes are disposed along the length of each fixation wing, the bone fixation holes being effective to assist in securing the fixation wing to pelvic bone.

12. The system of claim 11 further comprising a plurality of bone screws which, in cooperation with the bone fixation holes, secure the fixation wings to pelvic bone.

13. The system of claim 12 wherein the fixation wings are of a wedge-like structure in which the first end is narrower than the second end.

14. The system of claim 12 wherein the fixation wings are substantially L-shaped such that the second end of each fixation wing includes a segment that extends substantially orthogonally to the first end of the fixation wing.

15. The system of claim 12 wherein the fixation wings are substantially T-shaped, wherein a leg portion represents the first end and a head portion represents the second end.

16. The system of claim 12 wherein the fixation wings are rectangular.

17. The system of claim 1 wherein the length of the fixation wings is in the range of about 20 to 70mm.

18. The system of claim 1 further comprising a means for attaching each fixation wing to the flange portion of the reinforcement body.

19. The system of claim 1 wherein the flange portion is discontinuous.

20. A modular acetabular reinforcement system, comprising:

a substantially cup-like reinforcement body having a first end mountable within a patient's acetabulum and an opposed second end mountable adjacent a lip of the acetabulum, the second end including a flange portion extending along at least a portion of a perimeter thereof;

a plurality of selectively and separately attachable fixation wings, each fixation wing having a first end attachable to the flange portion and an opposed, second end attachable to bone;

means for selectively affixing the first end of at least one of the fixation wings to the flange;

at least one bone fixation hole disposed between the first and second ends of the fixation wing; and at least one bone fixation element for affixing the second end of the fixation wing to pelvic bone.

21. The system of claim 20 further comprising one or more bone fixation holes disposed in the reinforcement body, and one or more bone screws insertable within the bone fixation holes to secure the reinforcement body within a patient's acetabulum.

22. The system of claim 20 wherein the first and second ends of the reinforcement body are open ends.

23. The system of claim 20 wherein the means for selectively affixing comprises rivets.

.

24. The system of claim 20 wherein the means for selectively affixing comprises threaded fixation elements.