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Publication numberUS2934065 A
Publication typeGrant
Publication dateApr 26, 1960
Filing dateNov 1, 1954
Priority dateNov 1, 1954
Publication numberUS 2934065 A, US 2934065A, US-A-2934065, US2934065 A, US2934065A
InventorsCharles O Townley
Original AssigneeZimmer Mfg Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Femoral intramedullary prosthesis
US 2934065 A
Abstract  available in
Images(2)
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Claims  available in
Description  (OCR text may contain errors)

April 26, 1960 c. o. TOWNLEY FEMORAL INTRAMEDULLARY PRosTHEsIs 2 Sheets-Sheet 1 @am MJ J/ Filed Nov. 1. 1954 United States Patent O FEMORAL INTRAMEDULLARY PROSTHESIS Charles 0. Townley, Port-Huron, Mich., assignor to Zimmer Manufacturing Company, Warsaw, Ind., a corporation of Indiana Application November 1, 1954, Serial No. 465,792

2 Claims. (Cl. 12S- 92) The present invention relates to `femoral intramedullary prosthesis, and more particularly to prosthesis employed in connection with the hip joint to replace portions or all of the femoral head and neck.

The femur of the human leg is the largest and longest bone in the skeleton, and transmits the weight of the trunk of the body from the hip bone to the tibia or shin bone. In the erect posture it inclines from above downward, slightly backward or posteriorly, and medially or toward its fellow of the opposite side. At the upper end thereof it presents' a superior or proximal extremity including the femur head and neck and two trochanters which considered together may be termed the trochanter or trochanteric area; these portions merge into the substantially cylindrical femoral shaft formed with a narrow, elongate recess termed the medullary canal. The superior extremity of the femur is surmounted by a smooth globular portion called the head of 4the femur, which is directed upwardly for articulation with the acetabulum or hip joint socket of the hip bone. The head of the femur is generally hemispherical in shape and is connected with the femoral shaft by an upwardly directed column of bone called the neck of the femur, which forms with the shaft, in an adult, an angle of about 125 degrees. The trochanters are prominences that afford attachment for muscles, especially the rotator muscles of the thigh.

Occasionally it becomes necessary to replace a portion of the femoral head, or the entire femoral head and a portion of the neck, and in extreme cases the entire femoral head and neck due to the fact that the bone has become diseased or is fractured in such a manner that proper healing is unlikely. In such a case, it is necessary to remove the diseased or damaged portion of the bone and to insert a femur prosthesis which will take the place of the bone removed and in eiect provide a new hip joint.

Fernoral prostheses of prior practices have proved to be unsatisfactory in that they are difficult to insert, that lthey require considerable destructive osteotomization of vthe femur during surgical insertion, and that they Ibear on portions of the bone unsuited to resist the force directed :against them, thereby leading to abnormal dissolution of .the bone and loosening of the prosthesis.

It is a primary object of this invention to provide a femoral prosthesis lfor the hip joint which may be inserted with a minimum of diiculty and shock to the patient.

It is another object of the invention to provide a femoral prosthesis which requires a minimum of osteotomy and which receives and spreads the weight of the body in the same manner that the natural femoral head and neck does.

It is yet another object of the invention to provide a femoral prosthesis which prevents rotation or other movement of the portion thereof which replaces the femoral neck and/ or head at its junction with, or attachment to, the femur.

A further object of the invention is to provide a femoral prosthesis for the hip joint including a spherical cap or head which receives the weight of the trunk in a manner similar to the femoral head, and a stem which serves no significant weight bearing purposes but is shaped to cooperate with the femoral shaft to guide the spherical cap or head into its correct position as the prosthesis is inserted and to restrain the cap or spherical head from movement at its junction with or attachment to the femur.

In addition to the foregoing, it is au object of the present invention to provide femoral prostheses which are economical of manufacture, convenient in application, and capable of use in substantially all cases when the portion of the femur forming a part of the hip joint must be repaired.

Other objects and advantages of the present invention will become apparent in the following description of preferred embodiments of the invention and the preferred use thereof.

Now, in order to acquaint those skilled in the art with the present invention and with a preferred manner of using the invention, I shall describe, in connection with the accompanying drawings, preferred embodiments of the femoral prosthesis.

In the drawings:

Figure l is a plan viewof one form of femoral prostheses according to the present invention, which I prefer to designate type I;

Figure 2 is a cross-sectional view of a femur having the prosthesis of Figure l applied thereto, with parts shown in elevation;

Figure 3 is a cross-sectional view along the line 3-3 of Figure l;

Figure 4 is a plan view of a modied form of cup or head which may be employed in connection with my type I prosthesis;

Figure 5 is a plan view of a modified form of femoral prosthesis, which I prefer to designate type II, showing the head or cap thereof in section;

Figure 6 is a cross-sectionalview showing the prostheses of Figure 5 applied to a femur with parts shown in section;

Figure 7 is a plan view of another form4 of prosthesis, which I prefer to designate type III; and

Figure 8 is a sectional view showing the prostheses of Figure 7 applied to a femur, with parts shown in elevation.

According to the present invention, I provide a femoral prosthesis comprising au elongated rigid stem having substantially rectilinear proximal (upper) and distal (lower) ends positioned lat an obtuse angle to each other and a generally spherical head or cap element fixed to the proximal end of said stem. The respective ends of the stern are angled to the extent that when Ithe prosthesis is positioned on the proximal end of a femur, the proximal end of the stem and the spherical head are disposed with respect to the shaft of the femur at substantially the same angle that the femoral neck and head normally project from the femoral shaft, and the distal end of the stem lies in the plane of the femoral shaft, said distal end being positioned within the medullary canal of the femur. The inferior or lower side of the spherical head of the prosthesis is cupped or grooved or slotted to provide a cylindrical side wall or side surface that is parallel to the axis of the proximal end of the stem and an end wall or undersurface which is substantially perpendicular to the side wall. In iinal position the cupped or grooved portion of the head is fitted over the superior or upper portion of the remaining bone structure, with the bone structure being shaped so that the bottom surface of the groove or slot in the spherical head of the prosthesis bears directly against the remaining bone rather than rbeing spaced from it. vThe distal end of the stem of the prosthesis is tted into the medullary canal of the femur and the stem as a whole serves no significant weight bearing purpose, but only positions the superior endof the prosthesis in its correct position and prevents rotation and other undesirable movement of the spherical prosthesis head at its junction with, or attachment to, the femur.

I Adisclose herein three embodiments of the invention which are respectively adapted for use in three separate situations or conditions prevalent in disease or injury of the human hip, though it is to be understood that the invention is not limited to the three illustrated embodiments..

`One embodiment of the invention is peculiarly adapted for use when only the proximal portion of the femoral head must be removed. This embodiment, referred to hereinafter as Type I, includes a stern having a relatively long curvilinear portion separating the rectilinear proximal and distal ends, said curvilinear portion having is positioned in the medullary canal of the femur. In

the iinal position of the prosthesis, the superior portion of the remaining femur head bone is engaged by the end surface and undersurface of the cupped portion of the prosthesis spherical head, and the distal end-of the prosthesis stern is positioned in the medullary canal and is substantially parallel therewith. The stem is triflanged in configuration throughout its length and the triflange structure, in addition to the curvilinear nature of a portion of the stern, cooperates with the adjacent bonestructure to prevent any movement of the prosthesis spherical head between the head and the bone of the femur.

A second embodiment of the invention is adapted for use in cases wherein the entire femoral head and a portion of the neck must be removed. This embodiment, referred to hereinafter as Type II, includes a stern having a relatively long distal end and a relatively short proximal end separated by a relatively shoit curvilinear portion having a radius of curvature considerably shorter than the radius of curvature of the curvilinear portion of the first embodiment. The stern is inserted through a hole formed in the bone and the distal end thereof is positioned in the medullary canal. In the inal position of the prosthesis, the superior portion of the remainingY vtriflange structure cooperating with the adjacent bone structure to prevent movement of the prosthesis head.

A third embodiment, referred to hereinafter as Type III, of the invention is peculiarly adapted for use when the lentire femoral head and neck must be removed. They stem of this embodiment is triflanged throughout and includes a relatively long distal end and a relatively short proximal end; the proximal and distal rectilinear ends are not separated by a gradually curved portion, but rather are separated by a sharply angulated portion. In applying this form of the invention to the femur, a wedgeshaped'portion is cut out of the femur, in the trochanter area, approximately the length of the proximal end of the stem below the top of the femur, yand the portion of the femur above the osteotomized portion of the bone is then capable of being directed toward the hip joint socket. The stem of the prosthesis is inserted through this trochanter area and into the medullary canal. As the bend in the stem passes Ithrough the portion of the trochanter above the point that the femur was osteotomized, the proximal end of the stem correctly positions the superior end of the femur with respect to the hip joint. In the final position of the prosthesis, the superior 'portion 'of the femur is engaged by the side surface and undersurface of the cupped portion of the prosthesis spherical head and the long distal end of theprosthesis stem is positioned in the medullary canal and substantially parallel therewith. It will thus be seen that the upper portion of thel femoral trochanter is reformed as a femoral head and neck and the prosthesis head is angulated sufficientlyI from the femoral shaft and the pelvis to provide better femur movement; also, the stern simultaneously provides intramedullary lixation of the corrective osteotomy site, and an adequate angle for improved hip joint function.

From the foregoing, it will be obvious that the present invention provides substantial advantages over prior practices. For example, the femoral prosthesis provided results in the application of the force on the femur on that portion thereof which is best constructed to bear it, namely, 'the head and/ or neck of the femur, or, in the case where no femoral head and neck remain, on the relatively tough superior end of the femoral trochanter. The inner, relatively soft portions of the femur adjacent ythe medullary canal are not subjected to any significant force or stress as one applies weight to ones leg, these portions of the bone being relied on only, together with the angled proximal end of the prosthesis stern, to prevent undesired movement of the prosthesis and to maintain the prosthesis in the desired anatomical position.

sReferring now more particularly to the drawings, wherein like reference numerals indicate like parts throughout the several views, reference numeral 10 of Figures l-3 generally indicates the form of femoral prosthesis which 1 prefer to designate type I and which I prefer to use in cases where the femoral head and neck need not be removed. The prosthesis 10 comprises a spherical head or cap element 12 and an elongate angled stern 14 including proximal and distal rectilinear ends 13 and15. The head or cap 12 is formed in the shape of approximately a three-quarter sphere, with the fiat side11 thereof forming the inferior or lower part of the head or cap 12. The fiat side 11 is cuppedor grooved or slotted to provide a hollow space or cupped portion 16 comprising a cylindrical internal side wall or side surface 1S approximately parallel to the axis of rectilinear endlS and an end wall or undersurface 20 substantially perpendicular to said axis. The head o'r cap 12 maybe drilled and tapped as at 22 to receive the screw-threaded end of the stem 114. The head or `cap 12 is ordinarily provided in a number of sizes, standard sizes normally being fortythree, forty-five, forty-seven and forty-nine millimeters in diameter, and the head is cupped or grooved or slotted a depth of sixteen millimeters, though the depth may be greater if necessary. Y

The stem 14 comprises the rectilinear proximalrand distal ends 13 and 15 separated by the relatively long curvilinear portion '24. The distal end 15 tapers distally throughout its length and merges into a rounded Vdistal extremity 26. The distal extremity 26 is preferably angled somewhat with respect to the end 15, as shown in Figure l. The stem 14 is triflanged in cross-section, in the form shown in Figure 3, throughout the length thereof to preserve bone structure and to cooperate with the bone structure to prevent rotation of the stem.

I prefer to make the width of the proximal end 13 and the curvilinear portion 24 approximately twelve millimeters with the end.13 extending outwardly of the head or cap until it reaches a distance of approximately two inches from the top or superior portion of the prosthesis head. The ends 13 and 15are preferably angled at approximately one .hundred forty degrees with respect to each other, and the connecting curved v.portion 24 is preferably approximately three inches long and has a radius of curvature of approximately four inches. The distal end 15 tapers from a width of l2 millimeters at the point where it merges into portion 24 to 8 millimeters at its lower end; the rectilinear endlS is preferably approximately one and one-half inches in length. The distal extremity 26 is preferably angled approximately eight to ten degrees with respect to the end 1S in the direction that portion 24 curves in; preferably this latter angled portion includes a total length of approximately one-half inch.

The prosthesis of Figures l-3 is positioned on a femur approximately as shown in Figure 2, wherein the proximal end of a femur 30 is shown, including the lower portion of the femur head 28, the femoral neck 32, the greater and lesser trochanters 34 and 36, respectively, the femoral shaft 38, and the medullary `canal 40 within the femur. Figure 2 shows a cross-section through a right-hand femur (anterior view) in which the right-hand side is termed the medial side and the left-hand side is termed the lateral side. To insert the prosthesis, a portion of the femoral head 28 which is approximately equal in size to the solid part of the prosthesis head 12 is removed; the amount of bone removed will normally be the proximal one-third of the femoral head. This removal can be accomplished by using a flat broad osteotome or Stryker saw; care should be taken to make sure that the angle of the osteotorm'zed femoral head surface is such that the end wall of undersurface 20 of the cupped cap or head 12 will squarely engage the surface of the bone throughout its entire area when the prosthesis is in final position. A small hole approximately eight millimeters in diameter is then drilled approximately onequarter of an inch above the center of the osteotomized portion of the femoral head 28 to the medullary canal of the femur. For countersinking purposes, the proximal end of the hole is widened to eleven millimeters in diameter, to a depth of approximately three-eights of an inch. The distal extremity v26 of the prosthesis 10, which is rounded to prevent perforation of the bone cortex as the prosthesis is inserted, is positioned in the plane of the femoral head and neck and inserted approximately one-half of an inch; the head 12 is Vthen urged laterally to point the distal extremity 26 toward the medial side of the neck and the stem is driven around the curve of the neck by tapping gently on the head 12. The osteotomized area of the femoral head at this point should be inspected and reformed, if necessary, to insure that this surface is parallel to the undersurface 2? of the prosthesis head and then the cupped head or cap 12 is driven over the top of the femoral head with the excess of the bone around the margins of the femoral head being removed progressively as the prosthesis head is driven home. As shown in Figure 2, the cupped portion of the prosthesis head iits snugly over and grips the remaining portion of the femoral head and neck; the undersurface 20 engages the entire osteotomized surface of the femoral head and the side wall 18 of the prosthesis head engages the sides of the remaining femoral head to provide a maximum of surface on which the weight transmitted through the prosthesis bears against the bone.

As shown in Figure 2, the proximal end 13 is disposed in the plane of the femoral head and neck, and the distal end 15 is disposed within the medullary canal 40 and within the plane of the femoral shaft 3S, when the prosthesis is in its inserted position. The cupped portion of the prosthesis head fits snugly over the remaining portion of the femoral head and neck; the undersurface 20 of the prosthesis head 12 engages the entire osteotomized surface of the femoral head, and the side Wall 18 of the prosthesisA head engages the sides of the remaining femoral head to provide a maximum of surface on which the weight transmitted through the prosthesis bears against the bone of the femoral head. The stem serves no weight bearing purpose, but merely aids in the positioning of the prosthesis head 12 during insertion and prevents rotation of the head 12 on movement of the femur. It will be noted that the weight transmitted to the femur will be applied in the same area which nature intended,

6. that is, the femoral head and neck, and that no other portion of the femur must resist downward thrusts against it.

The vslight angulation of the distal extremity 26 is provided so that this portion of the prosthesis will act as a sled-runner during installation of the stem as the latter strikes the lateral cortex of the femur to effect a guiding action of the stem as it is being inserted.

The direction of the curve of the stem is thus along or in conformity with the natural path of the medullary canal.

Figure 4 illustrates -a modified prosthesis head 42 for use with the prosthesis stem shown in Figures l-3 in special cases. 'Ihe head 42 is similar to head 12, but the cupped portion of the head has a somewhat different configuration. In the head 42 the undersurface or end wall 44 slants from the outer or lateral periphery of the groove or cupped portion 46 to the opposite or medial periphery, substantially as shown in Figure 4 and preferably the surface or end wall 44 slants suiicient so that it is substantially horizontally disposed when the prosthesis is in position on a femur. In this -form of the prosthesis head, it has been found that a cupped portion` varying from ten millimeters at the outer periphery thereof to eighteen millimeters atthe medial periphery thereof, with the plane, slanted undersurface 44 making an angle of approximately twenty-five degrees with respect to a plane passed normally through the axis of end 13 of stem 14 and approaching a generally right-angled relationship with respect to the distal end 15 of the stern, is satisfactory, and, it is believed, adds to the Weight bearing efficiency of the prosthesis.

Figures 5 -and 6 illustrate a form of my prosthesis which is `adapted for use in cases where only a portion of the femoral neck remains. I prefer to designate this embodiment Type II. 'I'he Type II prosthesis 50 comprises a spherical cap or head 52 and an elongate stem 54 'including rectilinear proximal and distal ends 56 and 58. The spherical cap or head 52 is shaped similarly to cap or head 12 shown in Figures 1 and 2 Iwith the exception that the cupped portion 60 is not quite as deep as in the case of cap or head 12. The stem 54 comprises the relatively short proximal end 56 and the relatively long distal end 58 separated by a relatively short curvilinear portion 62. The end S6 and the curvilinear portion 62 are preferably round on cross-sectional configuration so `as to be somewhat more space consuming, as the portion of the medullary canal in which the end 56 and the portion 62 are disposed is relatively large, while the distal end 58 is trianged in the manner illustrated in Figure 3, with the exception of the lowest portion thereof comprising the rounded extremity 64; the distal end also tapers from the point where it merges into the curved portion 62 to the opposite end thereof, where it merges into the rounded distal extremity 64. The rounded extremity is provided to prevent perforation of the bone cortex as the prosthesis is inserted.

I prefer to make the diameter of the proximalv end 56 and the rounded portion 62 approximately twelve millimeters, with the proximal end being approximately threequarters of an inch in length `from the undersurface 20 to the point where it merges into the curved portion 62. The ends 56 and 58 are preferably angled at approximately one hundred forty degrees with respect to each other, and the connecting curved portion 62 is defined by a radius of curvature of approximately two inches. The long distal end tapers from twelve millimeters in width to approximately eight millimeters at the lower end thereof and is preferably approximately seven and onehalf inches long with the rounded extremity being approximately one-quarter inch long. The cap or head 52 is preferably grooved or cupped to a depth of twelve millimeters.

The Type II prosthesis of Figures 5 and 6 is positioned on a femur approximately as shown in Figure 6, wherethe lesser trochanter 72.

forms no heavy Weight Ibearing duty, but merely positionsV aci-:goes

in the proximal end of a femur 66 is shown including the Vlower portion oft-he femoral neck 68, the greater and lesser trochanters 70 and 72, respectively, the femoral shank 74 :and the medullary canal 76.V The prosthesis is introducedr'clo'se to the superior or upper lateral aspect or sideof the remaining neck and the rounded extremity ,64 is directed toward the medial side of the medullary canal (thepright side of Figure 6). As the long distal end moves downwardly in the Ymedullary canal, the rounded extremity'iinally strikes the later-al side of the canal due to the slight curve in the femoral shaft. At this point the proximal, ork upper portion of end 58 will impinge against the superior portion of the remaining femoral neck, at the lateral (left-hand side as shown in Figure 6) side thereof, and it may be'necessary to rongeur away a small amount of the lateral side of the yfemoral neck in this area to allow complete insertion of the stem 54. As the cap or head 50 settles toward the neck the insertion force is directed more lateralward (with respect to the cap or head 50) so that the cap `or head closes over and grips the remaining stub of the femoral neck in the same manner that the head 1-2 ofrFigures l-3 grips the remaining bone of femoral head 28. With respect to the Type II prosthesis, it is VrecommendedV that, when the patients condition Warrants, the adductors should be transplanted distally and the greater trochanter excised to prevent impingement of the trochanter against the superior margin ofY the acetabulum.

. In lthe embodiment of `Figures 5 and 6, the prosthesis is 'formed so that the -prosthesis head Si) will be positioned directly over the remaining portion of the femoral neck so that when weight is applied to the femur, the load transmitted by the prosthesis lpasses to that portion of the femur which nature intended to bear the load, name- Vly the femoral neck, and the medial or innermost portion of the shaft of the femur, directly surrounding and under Here again the stem 54 perthe prosthesis head as it is inserted and prevents rotation of the head once the prosthesis is in its final position. This necessarily follows since the stem is formed in conforrnity with the configuration or path of the medullary I canal. Y

Y Figures 7 and 8 illustrate a form of my prosthesis which I prefer to designate type III and which is adapted for use in cases'wherein the entire femoral head and neck `must be removed. The prosthesis 8i) comprises a spherical head or cap 82, similar to the cap or head of Figures 5 and 6 and an elongate Vstem 84; including a relatively short rectilinear proximal end 86 and a relatively long distal end 88vseparated by -a sharply angulated portion 87. The stem is triilanged throughout in the form shown in -Figure 3, theV distal end 88 merging into the rounded extremity 90. t

n I prefer to make the width of the proximal end S6 and the distal end 88 approximately twelve millimeters, except for the last one inch of the distal end, which may taper to -a width of eightV millimeters. The proximal and distal ends of the prosthesis are preferably about three inches and ten inches long, respectively, and are angled at approximately one hundred iifty degrees with respect to each other.

The type III prosthesis of Figures 7 and 8 is positioned on a femur approximately as shown in Figure 8, wherein the proximal end of a femur is shown including the osteotomized subtrochanteric area 92, the femoral shaft 94 and the medullary canal 96. The femoral head and neck ofthe femoral shaft 94 have been removed, usually because of the irreparable condition of the bone as a result of injury, flush with the trochanter area 92. In applying the prothesis Vof Figures 7 and 8 to the osteotomized femur shown in Figure 8, the femur is further osteotomized by cutting a wedge-shaped piece out of the bone along the line 98 which is preferably about three inches below the top o f the trochanter'area 92 so that the Vchanter area 92 with respect to the femoral shaft 94 and the acetabulum. As the long stem is tapped into the medullary canal and the cap or head 82 approaches the top of the trochantic area 92 the angled portion of the stem passes through the hole; as the point at which the proximal end 86 merges into the distal end 88 approaches lthe line 98, the trochantic area assumes its correct position with respect to the femoral shaft 94 and the acetabulum. While there is a moderate amount of impingement and diiculty of insertion as the angled portion 87 of the stem passes through the trochantic area 92, lthis has been found Vto be a minor problem. The superior end of the trochanter area is osteotomized suiciently so that the cupped portion of the cap or head 82 will fit down tightly over it in the manner described in connection with the other embodiments of the invention.

The prosthesis of Figures 7 and 8 is formed to take advantage of the portion of the femur best adapted for weight bearing purposes if it is necessary to remove the femoral head and neck, namely, the tough upper end of the trochanter area of the femur. Prosthesis is adapted to correctly position the osteotomized trochanter area at the correct angle with respect to the femoral shaft, and, when fixed in position, transmits the weight applied to the femur directly to the top of the reformed trochanter, which serves as the femoral head and neck. As in the other embodiments, the stem 84 serves no heavy weight bearing purposes, but guides the positioning of the trochanter arci/L92 and the spherical head or cap 82, and prevents the spherical head from shifting upon movement of the femur with respect to ones body. When the prosthesis is in place on the femur, the gluteus medius muscle is transplanted distally and is secured in place either by sutures or screws.

' The relativelysmall triangular cross sectional configuration employed in the stem of all of the embodiments of the invention, and the thinness of the head wall 18, permit maximum preservation of the bone both at the perimeter of the neck and head of the femur and the central portion thereof. The fact that the cupped portion of the prostheses heads are formed with angled rather than rounded corners also reduces the amount of bone that must be removed to apply the prosthesis.

Consequently, my invention provides for preservation of maximum bone structure, something which is khighly important in medical practice of the type to which my invention relates.

The head and stern of the various embodiments of the invention herein disclosed may be made from any suitable materials, though it is desirable that the material or materials used form a prothesis which is non-corrosive, non-irritating, and completely inert, and which may be subjected to sterilization procedures without harmful eiect.

The foregoing description and the drawings are given merely to explain and illustrate my invention, and the invention is not to be limited thereto, except in so far as the appended claims are so limited since those skilled in the art who have my disclosure before them will be able to make modifications and variations vtherein without departing from the scope of the invention.

' l claim:

Y l. A femoral head prosthesis comprising an elongated rigid stem including proximal and distal ends disposed at an obtuse angle with respect to 'each other, and a generally spherical head xed to the proximal en'd of saidstern,

said distal end of said stem having a longitudinal configuration conforming to that of the natural path of the medullary canal of the proximal end of the femur, said spherical head being cupped on its inferior side to receive a portion of the femur that is formed to be received within the cupped portion, said distal end of said stem terminating in a rounded distal extremity for protecting the cortex of the femur against penetration by said stem, whereby, said spherical head of said prosthesis takes the full Weight load that is applied to the femur and said stem acts only to guide the positioning of said head as said prosthesis is applied to the femur, and to brace said head against rotation.

2. The femoral prosthesis set forth in claim 1 wherein said rounded distal extremity is angled medially of the stem to act as a guide for said stem during insertion thereof after striking the lateral cortex of the femur.

References Cited in the file of this patent UNITED STATES PATENTS 2,718,228 Van Steenbrugghe Sept. 20, 1955 1U FOREIGN PATENTS 1,075,914 France Apr. 14, 1954 1,063,680 France Dec. 16, 1953 OTHER REFERENCES Journal of Bone & Joint Surgery for January 1952, advertising pg. 18. (Copy in Scientific Library.)

The Journal of Bone & Joint Surgery for January 1954, v. 36A, advertising pg. 39.

The Journal of Bone & Joint Surgery for February 1954, v. 36B, advertising pg. 24.

The Journal of Bone & Joint Surgery for January 1952, advertising pg. 4.

The Journal of Bone & Joint Surgery for July 1951, advertising pg. 4.

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US4101985 *Mar 18, 1977Jul 25, 1978Friedrich BaumannHip-joint prosthesis
US4279042 *Nov 26, 1979Jul 21, 1981Rush-Presbyterian-St. Luke's Medical CenterHip prosthesis
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US4630601 *May 12, 1983Dec 23, 1986Howmedica International, Inc.Bone nail for the treatment of fractures
US4712541 *Dec 19, 1986Dec 15, 1987Howmedica International, Inc.Bone nail and instruments for the treatment of fractures
US4800873 *Aug 31, 1987Jan 31, 1989Audell Robert AMethod for setting fractures
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US6224634 *Mar 2, 1998May 1, 2001Waldemar Link (Gmbh & Co.)Hip-joint endoprosthesis
US6626949 *Jul 13, 2000Sep 30, 2003Biopro, Inc.Diamond coated joint implant
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US7621962Jun 23, 2006Nov 24, 2009Biomet Manufacturing Corp.Modular resurfacing prosthetic
US7641699Jun 15, 2007Jan 5, 2010Unger Anthony SFemoral head calcar loading prosthesis
US7879042Mar 5, 2004Feb 1, 2011Depuy Products, Inc.Surface replacement extractor device and associated method
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US8353965 *Sep 2, 2005Jan 15, 2013Seitz Jr William HSmall joint orthopedic implants and their manufacture
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US8562690Feb 11, 2011Oct 22, 2013Zimmer, Inc.Modular revision femoral prosthesis
US8623093Jun 15, 2011Jan 7, 2014Zimmer, Inc.Sleeve for modular revision hip stem
US8808391 *May 7, 2012Aug 19, 2014T.J. Smith & Nephew, LimitedHip joint prosthesis
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US20130123933 *May 7, 2012May 16, 2013T. J. Smith & Nephew LimitedHip joint prosthesis
EP0477113A1 *Sep 17, 1991Mar 25, 1992Medinov SaProsthetic assembly for hip joint
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Classifications
U.S. Classification623/23.14
International ClassificationA61F2/36, A61B17/72, A61F2/00
Cooperative ClassificationA61F2002/30405, A61F2230/006, A61F2/3676, A61F2220/0025, A61F2/3601, A61B17/7283, A61F2002/30181, A61F2002/3611, A61B17/72, A61F2002/3654, A61F2/36
European ClassificationA61F2/36