Abstract A prosthetic hip joint comprises a femoral element formed with a ball head and a stem projecting from the head and adapted to be received within the upper end of a femur, and a generally hemispherical socket element adapted to be secured in the ilium at the acetabulum thereof and having an inner surface formed as a generally hemispherical cavity adapted to snugly receive the ball head. The outer surface of the socket element is subdivided at a step into a lower quarter-spherical region having a center of curvature lying above the center of curvature of the ballreceiving cavity, and an upper quarter-spherical region adjoining the lower region and having a center of curvature coinciding with the center of curvature of the ball-receiving cavity. The step between the two quarter-cylindrical regions is formed with a chamfer and both of these regions are formed with a plurality of criss-crossing grooves, in at least one of which is received a metal wire allowing the synthetic-resin socket element to be viewed in an X-ray. The ball head of the femoral element is formed with a neck that is tapered into the stem and forms a pair of shoulders thereon.
A prosthetic hip joint comprising: a femoral element formed with a ball head and a stem projecting from said head and adapted to be received within the upper end of a femur, and a generally hemispherical socket element adapted to be secured in a predetermined orientation in an ilium at the acetabulum thereof and having an inner surface formed as a generally hemispherical cavity having a single center of curvature and receiving snugly said ball head, and having an outer surface formed as a lower quarter-spherical region having a center of curvature lying above the center of curvature of said cavity and an upper quarter-spherical region adjoining and above said lower region and having a center of curvature coinciding with said single center of curvature of said cavity, said socket element being of uniform radial thickness throughout said upper region and of upwardly increasing radial thickness at said lower region.
Claim 2
Dependent Claim
150 words
A prosthetic hip joint comprising: a femoral element formed with a ball head and a stem projecting from said head and adapted to be received within the upper end of a femur, and a generally hemispherical socket element adapted to be secured in a predetermined orientation in an ilium at the acetabulum thereof and having an inner surface formed as a generally hemispherical cavity having a single center of curvature and receiving snugly said ball head, and having an outer surface formed as a lower quarter-spherical region having a center of curvature lying above the center of curvature of said cavity and an upper quarter-spherical region adjoining and above said lower region and having a center of curvature coinciding with said single center of curvature of said cavity, said socket element being of uniform radial thickness throughout said upper region and of upwardly increasing radial thickness at said lower region.
Claim 3
Dependent Claim
41 words
The joint defined in claim 1 wherein said outer surface is formed with a step between said lower region and said upper region, said radial thickness of said upper region being greater than the maximum radial thickness of said lower region.
Claim 4
Dependent Claim
14 words
The joint defined in claim 2 wherein said step is formed with a chamfer.
Claim 5
Dependent Claim
18 words
The joint defined in claim 2 wherein said outer surface is formed with a plurality of crossing grooves.
Claim 6
Dependent Claim
17 words
The joint defined in claim 4, further comprising a metal wire disposed in one of said grooves.
Claim 7
Dependent Claim
18 words
The joint defined in claim 5 wherein said one groove extends from said stop across the upper region.
Claim 8
Dependent Claim
37 words
The joint defined in claim 2 wherein said stem is tapered and said femoral element is formed with a neck joining said ball head to said stem, said neck blending at least partially smoothly into said stem.
Claim 9
Dependent Claim
21 words
The joint defined in claim 7 wherein said neck is formed on opposite lateral sides with a pair of separate shoulders.