Interlocking femoral components for revision arthroplasty with allografts

The use of interlocking screws has been advocated to fix major proximal femoral allografts to femoral prostheses. This study examines the effect of interlocking screws on strength of the component. Model femoral components were tested in axial compression. Drilling one hole diagonally (lateral to medial), drilling one hole anterior to posterior, or drilling one diagonal hole plus one anterior-to-posterior hole did not significantly decrease failure load compared to controls with no holes. However, two diagonal holes or horizontal, medial-to-lateral holes were weaker. Four cases have been done with proximal femoral allografts fixed to porous-coated femoral components with proximal and distal interlocking screws. Initial results in these cases are good.