Soft tissue fixation to bone. A biomechanical analysis of spiked washers.

The initial fixation strengths of two spiked-washer designs were evaluated using human femurs and fascia lata tissue. Fascia lata was attached to the femur using the fixation devices, and then each femur-washer-fascia lata complex was loaded in tension to failure. Load-elongation curves were recorded, the initial failure load, initial failure displacement, stiffness, ultimate load, and ultimate displacement were determined for each test, and failure modes were recorded. Results indicated that the 6-spike design provided superior initial fixation strength in the 19-mm diameter size. This washer design was then compared with two commercially available fixation devices: the spiked AO washer and soft tissue fixation plate. Fixation provided by the prototypal washer design was not different in most instances from that provided by the AO fixation devices. Based on these results, important design characteristics for soft tissue spiked washers are identified and discussed.