Abstract: An oblong acetabular cup which includes a cavity for receiving a bearing element is provided. The plane of the opening into the cavity is skewed relative to the prosthesis' longitudinal plane so as to achieve adduction correction, anteversion correction, or both adduction and anteversion correction. In certain preferred embodiments, the prosthesis is constructed from two components which can be oriented with respect to one another to achieve different directions and amounts of anteversion correction. In some embodiments, the two components form a cusp in the outside surface of the prosthesis. Surgical instruments and surgical methods for implanting the prostheses are disclosed.

Abstract: An acetabular prosthesis (8) having an orientable metal socket bearing (13) and a cup (10) for fixation to bone (6) is provided. The bearing (13) has a male taper (26) which locks into a corresponding female taper (28) formed in the cup (10). Two screws (15) are used to seat the bearing (13) in the cup (10) and to further secure the taper lock. The assembly of the apertures (4) through which bone screws (15) can pass to further secure the cup (10) to the patient's bone (6).

Abstract: A sinterable coating for an implantable prosthesis is provided having 1) interstices into which tissue or bone can grow, and 2) increased surface roughness which provides enhanced initial press-fit fixation. The coating includes at least two sets of particles having different mean diameters. The sizes and numbers of particles are chosen so as to produce a matrix of smaller particles in which are embedded a lesser number of spaced-apart larger particles. The smaller particles provide support for the larger particles, and the larger particles stand proud of the smaller particles to provide the enhanced surface roughness.

Abstract: An oblong acetabular cup which includes a cavity for receiving a bearing element is provided. The plane of the opening into the cavity is skewed relative to the prosthesis' longitudinal plane so as to achieve adduction correction, anteversion correction, or both adduction and anteversion correction. In certain preferred embodiments, the prosthesis is constructed from two components which can be oriented with respect to one another to achieve different directions and amounts of anteversion correction. In some embodiments, the two components form a cusp in the outside surface of the prosthesis. Surgical instruments and surgical methods for implanting the prostheses are disclosed.

Abstract: A ball and socket joint for implanting in the body is provided which comprises (1) a ball; (2) a cup with a spherical cavity, said cup to be affixed to bone; (3) a projection associated with the cup and extending into the spherical cavity at the geometric pole of the cavity; and (4) a bearing member surrounding a portion of the ball and rotatable within said spherical cavity, said bearing member including a walled aperture for receiving the projection, the rotation of the bearing within the cavity being constrained by engagement of a wall of the aperture with the projection.