US2668531A - Prosthesis for hip joint - Google Patents

Description

Feb. 9, 1954 E. J. HABOUSH 2,563,531

PROSTHESIS FOR HIP JOINT Filed Feb. 15, 1952 .Lric

INVENTOR. EDWARD J- HABOUSH BY 1 HIS A l T o l N tYs.

Patented Feb. 9, 1954 UNITED STATES PATENT OFFICE PKOSTHESIS FOR HIP JOINT Edward J. Haboush, Brooklyn, N, Y. Application FebruarylS, 1952, Serial. N 0, 271,684

10 Claims.

This invention relates to metallic prosthesis for degenerated or damaged joints of the human body and it relates particularly to a metallic ball and socket prosthesis for replacing a degenerated or damaged head or head and neck of the femur.

In some cases of injury to the hip joint, the

head of the femur or the neck andhead of the femur are so badly damaged or degenerated that the common techniques for repair of the damaged parts are impractical or ineffective. For example, the relatively common practice of fixing a fractured femur or the neck thereof by means of bone nails or bone plates is impractical when the head of the femur is shattered or chipped to sucha degree that it cannot move freely in the acetabulum (socket) of the hip joint.

It has been suggested that such a badly shattered or chipped head of the femur could be replaced or repaired by means of a metallic orother artificial head or covering for the head of the femur. I have proposed that the damaged femur head could be repaired by reshapingit and applying to it a hollow head formed of a chrome, cobalt, molybdenum alloy (Haynes Stellite No. 21). The hollow head is provided with a spike which is driven lengthwise of the neck of the femur to form a rigid support for the metallic head. In practice, I found it difficult to seat the hollow head properly because it is impossible to see the position of the spike as it is being driven along the neck of the femur. Because of this difficulty, I suggested a modified type of head prosthesis which includes a short metallic flange or skirt to aid in guiding the head into position. This type of head was more readily applied and seated than the earlier type but it and theearlier type were found to have disadvantages which arose after the prosthesis had been in use for a relatively short period of time. It was found that with both of these types of prosthesis thatythe motion of the joint decreased progressively and the patient began to experience pain at the joint. Upon reoperation'to relieve the pain, it was found that the metallic headhad eroded the acetab ulum and the head itself had become slightly roughened thereby causing undesirable friction at the joint. Apparently, the differences in the hardness of the two relatively moving surfaces and the concentration .of the stresses on areas of the bone by the denser and harder material of the prosthesis caused the erosion and deepening of the acetabulum with a. consequent lossof proper fit. between the ball or headand the acetabulum.

My experience with the prior types (if-prom thesisled me to the conclusion that the head, as well as the receiving socket, must be made of appropriate materials of similar density and resistance to erosion and corrosion and that an improved structure for seating and maintaining alignment of .the prosthesis was required in order to provide a proper-restoration or replacement of the damaged joint.

In accordance with the present invention, I have provided an improved form of prosthesis for the repair of the hip joint which includes a balllike head member having a sleeve extending therefrom to receive and fit over the reshaped neck and head of the femur to provide a firm and solid union between them and to anchor theball and sleeves with bolts extending through the outer cortex of the femur. I have also provided for cooperation with the ball-like head a complementary socket formed of a similar material which is precision fitted to the hall to minimize friction between them and prevent the concentration of stresses at limited areas of the head and the socket. Ihave also found it highly desirable to secure the head or ball in position on the femur by means of a quick-setting resinous material, such as, a quick-hardening acrylic resin andalso to secure the socket in position in the pelvic arch, by meanspf a. similar quick-setting resin which serves not only to bond the elements together but to afford a cushioning action which absorbs and distributes the shock throughout a sreaterarea of the bone structure and this minimizes wear, erosion and pain. By providing a precision fitted head and socket, lubrication of x the "surfaces can :be accomplished with a minimum;of the body fluids, such as lymph or the like, so that the ball to all intents and purposes floats inthersocket and thereby is subjected to a minimum of wear. To obtain thi-s effect, the surfaces preferably should be fitted to within /1uo,0co of an inch, although somewhat greater tolerances are possible.

flheprovision of a separate metallic socket has the advantage that it overcomes the need to fit he acetabulum closely to the head of the ball, such practice being practically impossiblein any event, during an operation of the nature required. Through. the. use of. theresinous bonding material, irregularities which. are produ ed during the enlargement of thewacetahulum, to receivethe metallic socket are. obviatedand an ccurate and precise location and fitting of the socket of my new prosthesis readily obtained.

Fora better understandinsof the presentina vention, reference may be had to the accompanying drawing in which:

Fig. 1 illustrates my new prosthesis shown partly in elevation and partly in section as applied to the femur and to the pelvic bone at the zone of the acetabulum; and

Fig. 2 is a View in section taken on line 2-2 of Fig. 1.

Referring to Fig. 1, the prosthesis is shown as applied to a femur F and to the pelvic bone S to repair a damaged femur head in which the neck of the femur has not been fractured. The ball member of the prosthesis consists of a hollow ball-like head I formed of a corrosion-resistant alloy of chromium, cobalt and molybdenum (Haynes Stellite No. 21) or a wrought sheet alloy such as Haynes Stellite No. 25. The ball-like head has a tapered or frusto-conical hollow skirt or collar II projecting from one side thereof. The collar I I may be symmetrical with respect to an axis passing through the center of the balllike head M3 for it has been found that with such a skirt construction, the same type of ball and skirt construction can be used for repair of either the right or left hip joint. v

The outer end of the skirt II is provided with a flared or laterally extending fiange I2 having two or more apertures I3 and I4 for the reception of the bolts I5 and IE to secure the ball and skirt to the femur F. The use of bolts to secure the ball and sleeve to the femur contributes greatly to the strength thereof. In particular, the bolts keep the prosthesis from working off the portion I? and relieve it of almost all of its loading. The portion I'I' merely provides resistance to shearing forces while the binding load is taken by the bolts.

In applying the ball and skirt to the head and neck of the femur, the head and a portion of the neck are carved or chiseled to the generally conical form I'I illustrated in Fig. 1. The over-all length of the conical portion I I will, of course, vary depending upon the extent of damage to the head and neck of the femur. The conical portion H should be reduced in size so that it fits tightly within the skirt II when the latter is seated firmly on the portion IT. The inner surface of the skirt Il may be provided with a plurality of small sharp-edged ridges or knife edges I8 which penetrate into the bone and retain the head and skirt against rotation relative to the portion II. Also, to prevent distortion of the head It and reinforce the connection with the conical portion H of the bone, the head may be filled with a quick-setting resin such as an acrylic resin is which hardens by polymerization, or evaporation of a solvent after application and thereby produces a solid filling within the head.

In some cases, the neck of the femur may be fractured or may be severely damaged so that it cannot be fitted tightly within the skirt II. In such case, a bone nail may be driven through the femur along the axis of the neck and the nail itself together with the resinous material I9 will form a strong support for the ball and skirt.

The ball portion I0 does not cooperate directly with the acetabulum or the normal socket. A metallic socket 28 formed of the same material as the ball IE3 or a similar material is provided to receive the ball III. The socket 20 and the ball III are precision fitted to each other by a grinding and lapping operation which makes their surfaces complementary. The closer the fit of the socket 29 to the ball III, the better the operation of the joint. Preferably these elements should be fitted within about of an inch to assure best operation. However, somewhat greater tolerances may be used in the manufacture of the prosthesis, but in any event, the motion of the ball in the socket should be smooth and capable of almost frictionless movement in the presence of only a small amount of the lubricating fiuid, such as body lymph.

In most cases, the socket 29, although formed of material on the order of 0.125 inch in thickness, will not fit within the normal acetabulum so that it is necessary to chisel or otherwise form a recess of somewhat larger than natural dimensions in the bone. Because of the fact that it is not possible to produce a recess which precisely fits the back of the socket 20, and, in fact, it may not be desirable to do so, the socket 29 is secured in the bone S by means of a thin layer 2i of quicksetting hesin, such as the acrylic resin referred to above. The layer of resin 2| is shown greatly exaggerated in Fig. 1 as is the thickness of the socket it. To assure a firm bond between the socket 2B, the resin 2i and the bone S, the back of the socket may be provided with a series of small undercut or dovetailed recesses or grooves 22 into which the resin may flow and harden. Also a series of small undercut recesses 23 may be formed in the bone S to receive the resin. In this way, a strong mechanical bond is obtained between the metallic socket 2B and the bone S. Further, the outer edge of the socket may be cut back to form an outwardly facing shoulder 25 over which the resin can flow to key the socket 253 to the resin and retain it against outward movement. Also, the resin will flow smoothly up to the edge of the socket 2i) and thereby form a joint which is free of sharp edges which might cut or lacerate the adjacent tissues.

It has been found that joints including my prosthesis are capable of withstanding loads comparable to those which an undamaged femur can support without a substantial concentration of stresses at restricted areas of the joint. Moreover, the surface tension between the closely fitted ball and socket is such that the smallest drop of body fiuid becomes a thin lubricating film between the opposed surfaces of the ball and socket. Due to the presence of such a lubricating film, very little wear can occur on the ball and socket. Moreover, because of the presence of the acrylic resin or the like, vibrations or shock are absorbed to a degree that pain-like sensations ar largely eliminated. Another important feature of the closely fitted surfaces is that air pressure will tend to hold them together so that, while they can be moved readily, they cannot be separated without the application of a very substantial force.

It has also been found that the smooth juncture of the metallic prosthesis with the bone structure permits the body tissues to grow over the joints between the prosthesis and the bone and thereby form natural covering for the edges of the metallic elements. It also provides for a more extended range of movement and distributes the weight over a larger area.

It will be understood that the prosthesis disclosed herein may be made in several sizes de- .pending upon requirements and they may. be made of various types of corrosion-resistant metals or materials. Therefore, the form of the invention disclosed herein should be considered as illustrative and not as limiting the scope of the following claims. Y

I claim:

1. A hip-joint prosthesis comprising a hollow ball member of corrosion-resistant metal, a hollow tapered sleeve extending from one side of said ball member to receive the reshaped head and neck of a femur, said sleeve having its smaller end fixed to said ball member, a socket member of corrosion-resistant metal fitted to said ball member for free rocking movement relative thereto, and means forming recesses on the back of said socket member to secure said socket member in position with respect to the pelvic arch.

2. The prosthesis set forth in claim 1, comprising a plurality of sharp-edged ribs extending lengthwise, and on the inside, of said sleeve.

3. The prosthesis set forth in claim 1 in which the ball and socket have opposed lapped surfaces fitted to each other within a tolerance of about 0.00001 of an inch.

4. A hip-joint prosthesis comprising a hollow ball member corresponding to the head of the femur, a hollow sleeve extending from one side of said ball member and communicating with the interior thereof to receive the neck of the femur, and a flange extending laterally from the outer end of said sleeve and having apertures therein to receive fasteners to secure the ball and sleeve to the shaft of the femur, said ball, sleeve and flange being integral and formed of corrosionresistant metal.

5. The hip-joint prosthesis set forth in claim 4, in which said sleev tapers inwardly from said flange to said ball and is substantially symmetrical about an axis passing through the sleeve and the center of said ball.

6. The hipjoint prosthesis set forth in claim 4 comprising a plurality of sharp edged ridges on the inner surface of said sleeve and extending lengthwise thereof.

7. The hip-joint prosthesis set forth in claim 4 comprising a thin metal socket member having a cavity in the front thereof to receive and fit the outer face of the ball, said socket having recesses in its back to receive and interlock with a bonding material to secure the socket member in position.

8. The hip-joint prosthesis set forth in claim 4 comprising a thin metal socket member having an outwardly facing substantially hemispherical cavity ther in to receive and fit said ball and a substantially circular outer edge, said socket member having a laterally extending shoulder extending circumferentially around it behind and outwardly of said circular edge and facing in substantially the same direction as said cavity to receive bonding material behind and in front of said shoulder to secure said socket member in position.

9. A hip-joint prosthesis for a damaged head or neck and head of the femur, comprising a hollow ball member of corrosion-resistant material adapted to receive the reshaped head of a femur, a sleeve integral with said ball member adapted to receive the reshaped neck of the femur in tightly'fltted relation, said head and sleeve being adapted to receive a quick-setting resin to fill any space in said ball and sleeve not occupied by the reshaped neck or neck and head of the femur, a flange on the outer end of said sleeve, means to securesaid flange to the shaft of the femur, a socket member formed of thin corrosion-resistant metal having a substantially hemispherical cavity therein receiving and fitted to said ball member with capacity for relatively frictionless rocking movement relative thereto, said socket member being adapted to be mounted in the pelvic bone with a layer of a quick-setting resin.

10. A hip-joint prosthesis comprising a hollow ball member corresponding to the head of the femur, a hollow, tapered sleeve extending from one side of said ball member and communicating with the interior thereof to receive the neck of the femur, said sleeve having its smaller end adjacent to said ball member, and means at the outer end of said sleeve to receive fasteners to secure the ball and sleeve to the shaft of the femur, said ball and sleeve being integral and formed of corrosion-resistant metal.

EDWARD J. HABOUSH.

References Cited in the file of this patent The Journal of Bone and Joint Surgery, January 1952, pp. -6.

Journal of International College of Surgeons, August 1941, pg. 292.

Journal de Chirurgie for January 1926, pp. 51-2.

(Copies of these publications in Div. 55.)

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