Synthetic composite femurs for use in evaluation of torsional stability of cementless femoral prostheses

The present study describes commercially available synthetic composite femurs, and evaluates their suitability in assessing femoral prosthesis stability. Torsional stability of one type of uncemented femoral prosthesis was compared in cadaver and synthetic femurs by measuring prosthesis rotations relative to the femur in torsional loading. Relative rotations of different stem designs of femoral prostheses were compared in synthetic femurs. With the same stem design, relative rotations were similar in fresh frozen, embalmed and synthetic femurs. In these synthetic femurs, sensitivity to stem design is shown by the difference of relative rotations for different stem designs. Comparisons showed synthetic femur shape and dimensions to cadaver femurs were within published ranges.