Hip prosthesis
AssigneeJohnson & Johnson Orthopaedics, Inc.
InventorsWilliam H. Hoffman, Richard D. Scott, James A. Rand
Life of this patent
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Abstract
A hip prosthesis is disclosed which employs a number of cement spacers located on the surface of the stem of the prosthesis immediately below a collar which makes direct and parallel contact with calcar bone when a stem of the prosthesis is seated in medullary canal of the patient. The collar is constructed to provide even stress distribution to the bone.
Claims8
A femoral component of a hip prosthesis comprising a neck adapted to receive a ball head, a collar having a proximal surface on the side of the neck and a distal surface on the side of a stem, said stem being capable of insertion into the medullary canal of the femur of a patient, said collar having a cross sectional area larger than the cross sectional area of part of the stem adjacent the collar, said stem having anterior, posterior, medial and lateral surfaces, and said collar having anterior, posterior and medial edges that extend beyond the anterior, posterior and medial surfaces of the stem, a cement spacer located on each of the anterior, posterior and medial surfaces of the stem, each of said spacers having a generally circular cross section and having a proximal edge and a center line through the center of said spacer, each of said spacers extending outwardly from the stem surface on which it is located, said spacers being affixed to the stem immediately adjacent the distal surface of the collar whereby the spacers may position the stem when the stem is placed in the medullary canal of the femur of a patient.
Dependencies are inferred from the claim text.