Design Rationale and Clinical Experience with the LSF Hip System

 

The LSF (Long-Term Stable Fixation) Total Hip System (Implant Technology, Inc., Secaucus, NJ) was designed to address many of the obstacles in non-cemented total hip replacement. Although total hip arthroplasty utilizing contemporary cementing techniques has proven to be an extremely successful clinical procedure, the problem of long-term fixation remains unsolved. This has been a particular problem in younger more active patients. It was these long-term problems which lead to the general enthusiasm for alternate methods of implant attachment, including bone growth into a porous-surfaced implant.19 Among the obstacles which must be overcome when utilizing biologically attached implant systems are micromotion at the implant -tissue interface (which results in fibrous rather than bone tissue in growth), subsidence of the femoral component, and stress shielding due to failure of the implant design to reproduce adequately anatomical stress distribution. Torsional loosening of components, the potential for fatigue failure due to the reduced material properties of a porous-coated device, and a limited...