Quadricepsplasty for Patellar Obligate (Habitual) Lateral Flexion Dislocation.

Abstract

There are multiple underlying etiologies of patellar instability including both osseous and soft-tissue factors. Obligate flexion dislocation consists of lateral dislocation of the patella, occurring each time the knee flexes. This generally results from a predominantly lateral contracture of the extensor mechanism and can be technically challenging to manage. Quadricepsplasty can be of particular clinical utility for obligate flexion dislocation and constitutes a realignment of the proximal soft-tissue attachments of the patella. The described technique features isolation of the 4 muscles of the quadriceps and subsequent stepwise lengthening of the vastus lateralis, advancement of the vastus medialis obliquus, and Z-lengthening of the rectus femoris and vastus intermedius. This technique can be used in isolation or in combination with other procedures, such as medial patellofemoral ligament reconstruction, to surgically address patellofemoral maltracking.