Stability of the knee after posterior cruciate ligament reconstruction using peroneus longus tendon graft with three femoral insertion sites. A cadaveric study

INTRODUCTION: Many kinds of grafts were used for single-bundle reconstruction of the posterior cruciate ligament (PCL). Recently, the peroneus longus tendon (PLT) was used in some clinical reports. This study aimed to test the best position of the femoral insertion in the case of using PLT for PCL reconstruction. METHODS: Seventeen fresh frozen cadaveric knees were randomized into three groups. Group AL (6 knees): the femoral insertion in PCL reconstruction was at the footprint center of the anterolateral bundle (ALB). Group PM (5 knees): at the footprint center of the posteromedial bundle (PMB). And group MC (6 knees) was at the midpoint of the center of the anterolateral bundle and posteromedial bundle. The PCL of all knees was cut and a PCL reconstruction procedure was performed with autologous peroneus longus tendon (PLT). The stability of each knee was tested in three conditions: PCL was intact, PCL was resected, and PCL was reconstructed. The KT-1000 machine was used to measure the maximum posterior displacement of the tibia under force with the knees at 0, 30, 60, 90, and 120 degrees of flexion. RESULTS: Average posterior displacement of the tibia under force for intact PCL of group AL was 1.6 mm, group MC was 1.2 mm, and group PM was 1.3 mm. After PCL was resected, the knee laxity was increased remarkably: posterior displacement of the tibia of group AL was 8.9 mm, group MC was 9.4 mm, and group PM was 13.6 mm. After PCL was reconstructed, group AL was 1.5 mm, group MC was 2.0 mm, and group PM was 5.6 mm. The results showed that after PCL reconstruction the group AL and group MC give better stability to the knee (p < 0.05, except knee at 120 degrees of flexion). Group AL got more stability than group MC, but the difference was not significant (p ≥ 0.164) CONCLUSION: In a single-bundle reconstruction of the PCL with the graft PLT, the femoral insertion at the footprint center of the ALB and the midpoint of the center of the ALB and PMB showed better stability than that at PMB.