A TECHNIQUE FOR THE EVALUATION OF THE CONTRIBUTIONS OF KNEE STRUCTURES TO KNEE MECHANICS IN THE KNEE THAT HAS A RECONSTRUCTED ANTERIOR CRUCIATE LIGAMENT

A technique to quantify the restraining action of specific knee struct ures during anterior/posterior (A/P) tibial displacement tests in the goat knee that has a reconstructed anterior cruciate ligament (ACL) is described. Joint specimens were mounted in an instrumented test stand to measure both the forces on, and resulting translations of, the tib ia in the A/P direction. The intact grafted knee was tested first, aft er which structures were sequentially cut or removed, or both, and the test was repeated. The ACL graft remained intact in the joint during this process; therefore, subsequent axial failure testing was possible . Analysis of the resulting force-displacement curves allowed the perc entage contribution and anterior joint stiffness to be determined for each structure at a fixed anterior displacement in 12 goat knees 6 mon ths after ACL allografting. The allografts were found to provide about 56% of the total restraining force, more than any other structure exa mined. Studies of this kind will be important in the documentation of the changing role of an autograft or allograft in a reconstructed knee over time.