A Biomechanical Comparison of Lateral Retinacular Releases

Abstract

A lateral patellar retinacular release that transects the tendon of the vastus lateralis muscle may result in sig nificant complications. To avoid such complications, the superior extent must be limited, and maximizing the in ferior extent may be important in achieving an adequate release. The effective release of the patella from its lat eral retinaculum was examined for 2 incision lengths using 10 fresh-frozen human cadaveric knees and com paring the medial displacement of the patella relative to the femur for 3 study groups (control, intact retinacula; Group A, retinacula cut from the inferior third of the vas tus lateralis tendon down to the anterolateral arthro scopic portal; and Group B, retinacula cut from the in ferior third of the vastus lateralis tendon down to the tibial tubercle) when a 22-N medially directed force was applied to the patella with the knee at 30° and 60° of flexion. The extended release (Group B) resulted in a significantly more effective release when compared with the standard release (Group A) or control group. This technique may allow an adequate release of the patella while preserving the function of the vastus late ralis muscle.