Extramedullary femoral head-neck prosthesis and method of implanting same
First Claim
1. An extramedullary femoral head-neck prosthesis for implantation in a femur having a shaft and a neck at the medial side of the femur, comprising:
- a sideplate;
means for securing the sideplate to the femur shaft at the lateral side of the femur;
a barrel extending obliquely upwardly from the sideplate and having an open upper end, said barrel being adapted to be inserted in a bore extending obliquely upwardly through the shaft of the femur from the lateral side of the shaft to the neck of the femur;
a ball assembly comprising a ball stem having a central longitudinal axis adapted to be inserted coaxially into the barrel through the open upper end of the barrel and to be slideably received therein, said ball stem being sized for a relatively closed clearance fit in said barrel, a collar at one end of the stem, constituting its upper end, adapted for face-to-face engagement with the neck of the femur, a neck on the collar, and a ball on the neck, said neck having a central longitudinal axis which is skewed relative to the central longitudinal axis of the stem so that the center of the ball is offset medially from the longitudinal axis of the stem; and
retainer means for holding the ball stem against upward movement of the stem in the barrel.
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Accused Products
Abstract
An extramedullary femoral head-neck prosthesis for implantation in a femur, the latter having a shaft and a neck at the upper end of the shaft at the medial side of the femur. The prosthesis comprises a sideplate and screws for securing the sideplate to the lateral side of the femoral shaft. A barrel extends obliquely upwardly from the sideplate and has an open upper end. The barrel is adapted to be inserted in a bore extending obliquely upwardly through the femoral shaft from the lateral side of the shaft to the femoral neck. The prosthesis also includes a ball assembly comprising a ball stem adapted to be inserted coaxially into the barrel through the open upper end of the barrel and to be slideably received therein, a neck at the upper end of the stem adapted for face-to-face engagement with the femoral neck, and a ball on the neck. The ball stem is sized for a relatively close clearance fit in the barrel. The ball stem is retained and held against upward movement in the barrel so that the neck of the ball assembly presses against and compresses the femoral neck. A method of implanting such a prosthesis is also disclosed.
144 Citations
9 Claims
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1. An extramedullary femoral head-neck prosthesis for implantation in a femur having a shaft and a neck at the medial side of the femur, comprising:
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a sideplate; means for securing the sideplate to the femur shaft at the lateral side of the femur; a barrel extending obliquely upwardly from the sideplate and having an open upper end, said barrel being adapted to be inserted in a bore extending obliquely upwardly through the shaft of the femur from the lateral side of the shaft to the neck of the femur; a ball assembly comprising a ball stem having a central longitudinal axis adapted to be inserted coaxially into the barrel through the open upper end of the barrel and to be slideably received therein, said ball stem being sized for a relatively closed clearance fit in said barrel, a collar at one end of the stem, constituting its upper end, adapted for face-to-face engagement with the neck of the femur, a neck on the collar, and a ball on the neck, said neck having a central longitudinal axis which is skewed relative to the central longitudinal axis of the stem so that the center of the ball is offset medially from the longitudinal axis of the stem; and retainer means for holding the ball stem against upward movement of the stem in the barrel. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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Specification