Abstract
Abstract
Introduction
Historic MCL reconstruction techniques focused on the superficial MCL to restore valgus stability while overlooking tibial external rotation and the deep MCL. This study assessed the ability of a contemporary medial collateral ligament (MCL) reconstruction and a deep MCL (dMCL) reconstruction to restore rotational and valgus knee stability.
Methods
Six pairs fresh-frozen cadaveric knee specimens with intact soft tissue were tested in four states: 1) intact 2) after sMCL and dMCL sectioning, 3) contemporary MCL reconstruction (LaPrade et al), and 4) dMCL reconstruction. In each state, four loading conditions were applied at varying flexion angles: 8Nm valgus torque, 5Nm tibial external rotation torque, 90N anterior drawer, and combined 90N anterior drawer plus 5Nm tibial external rotation torque.
Results
Transection of the sMCL and dMCL resulted in increased laxity with valgus torque, external rotation torque, and combined anterior drawer plus external rotation. dMCL reconstruction restored external rotation stability to intact levels throughout all degrees of flexion but did not restore valgus stability at any flexion angle. Contemporary MCL reconstruction restored valgus and external rotation stability at 0° and 20° and valgus stability at 40°. In the combined anterior drawer plus tibial external rotation trial, the dMCL restored stability at 20° and improved stability between 40° and 90° flexion. Conversely, the contemporary MCL reconstruction did not restore stability at any degree of flexion.
Conclusion
Deep MCL reconstruction restored rotational stability to the knee throughout range of motion but not valgus stability. The contemporary MCL reconstruction restored stability only near full extension.