Screw anchored joint prosthesis

Abstract

Screw-based primary fixation of the prosthetic components within the medullary cavity solves the problem of micro-movements encountered in conventional press-fit cementless fixation. For a total hip prosthesis, the stem is fixed to the medial cortex of the proximal femur by the medial approach alone, obviating the need for drilling of the lateral cortex. The stem may be implanted using special drill guide instrumentation. Anchoring screws are locked into the stem of the femoral component, while self-cutting threads on the screw head engage the pre-drilled medial cortex. This novel fixation principle can also be applied to other joint prostheses, e.g. finger, shoulder, elbow and knee, as well as to dental and spinal implants.

Description

technical field [0001] The present invention generally relates to an improved joint prosthesis. Background technique [0002] In the three decades since total hip replacement (THR) became widely accepted, the practice of orthopedic surgery has changed. A whole new industry has sprung up in support of THR. More importantly, THR has improved the quality of life of millions of patients in a procedure unmatched by any other single procedure in the history of surgery. All of this was originally possible with the advent of cemented THR. Within the first decade following Charnley's pioneering work, a broad base of surgeon training, a highly stimulated industry, and an enabling health insurance policy had led to worldwide acceptance of THR, as evidenced by the number of people undergoing this procedure. Exponential growth, currently proven in over 600,000 per year worldwide. [0003] But this early period of boundless optimism was followed by waves of innovation, when results of ...

AI Technical Summary

Problems solved by technology

[0011] *In the acetabular component, the difficulty of matching the implant to the highly compliant spongy bone, with or without cement, can lead to the formation of soft tissue at the interface so that general instability can develop;

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