To compare differences in the biomechanical characteristics of posterior cruciate ligament (PCL) reconstructed by the inlay and transtibial techniques.

PCL reconstruction was performed in 12 pairs of porcine hindlimbs using the inlay and transtibial techniques. Cyclic load testing was carried out in three steps. The first step was 750 cycles at 35-350 N, the second 10,000 cycles at 35-350 N, and the third 10,000 cycles at 45-450 N. Length changes of the reconstructed PCLs were measured and the sites of rupture observed.

Among the 10 pairs of limbs that completed the test procedure, the graft ruptured before step 3 in all specimens except one in the transtibial group, and seven specimens completed step 3 testing in the inlay group. Comparing the load elongation curves obtained in step 2 tests, more elongation of the graft was evident in the transtibial group (p<0.05). The site of rupture was proximal 1/3 (2 specimens) or distal 1/3 (1) to the graft in the inlay group, and in the distal 1/3 for all specimens of the transtibial group.

These results suggest that the tibial tunnel orifice renders a risk of attritional rupture to the graft in the transtibial technique. In this respect, the inlay technique has a biomechanical advantage over the transtibial technique.