Medial patellofemoral ligament restraint in lateral patellar translation and reconstruction.

The purpose of this investigation was to evaluate the prevention of lateral patellar displacement by the medial patellar stabilizers and the effectiveness of medial patellofemoral ligament (MPFL) reconstruction against lateral displacement. Ten fresh frozen human knee specimens were studied and anatomical observations were made using seven additional knee specimens. Lateral shift ratios were measured, using a lateral force of 10 N, after sectioning the medial retinaculum and/or the MPFL during 20-120 degrees of knee flexion. The isolated sectioning of the MPFL greatly increased lateral displacement during 20-90 degrees, and the isolated MPFL reconstruction prevented patellar displacement within the normal range during 20-120 degrees.