Operative Treatment of Chronic Pediatric Patellar Instability

Chronic patellar instability in the pediatric population presents early in life and can present as a permanent irreducible dislocation or a habitual dislocation with knee flexion. Congenital patellar dislocation tends to present at birth, with a knee flexion contracture, valgus malalignment of the lower limb and external tibial torsion. Habitual dislocation may present later. The pathoanatomy of congenital and habitual dislocation differentiate. Accurate diagnosis of the underlying pathology is important as the operative management of these conditions is based on addressing these underlying pathologies and so a thorough history and clinical exam is vital. Plain radiographs generally provide the information required to make a diagnosis and plan operatively. Nonoperative management tends to lead to poor long-term outcomes but there is poor consensus in the literature regarding the operative treatment of these conditions. The evaluation and operative treatment of these conditions is described in detail here, addressing the extensor mechanism rotation or attachment abnormalities, the lateral position of the patellar tendon insertion and the laxity of the medial soft tissues.