Ortho Development Corporation

Bruce Shepherd

Timothy McTighe

Jerry Kee

A modular hip stem prosthesis including a separate and interchangeable stem piece and proximal shoulder piece. Coronal and sagittal slots are formed in a rounded distal end of the stem in a substantially right-angle orientation. A neck member extends angularly outward from the shoulder piece and is configured to receive a spherical hip ball for insertion into the hip socket. The proximal shoulder piece includes a cylindrical projection for insertion into an axial bore formed in an upper end of the stem. An annular lip is formed in side walls defining the axial bore, and a distal end of the cylindrical projection abuts the lip when it is inserted into the bore. Radial teeth are formed on a distal end of the cylindrical projection and mate with compatible teeth formed on the annular lip to thereby render the shoulder piece removably mountable onto the stem. A locking screw securely joins the shoulder piece with the stem. The stem piece can be unitary or made up of a separate and interchangeable distal stem piece and metaphyseal component. The shoulder piece is selectable from an array of shoulder pieces having various heights and lengths to thereby provide spacing in two dimensions between the femur and the pelvis which reduces the risk of hip dislocation without introducing the problems of leg elongation and femur splintering.

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Mosman, Australia

Bruce Shepherd