Management of ACL elongation in the surgical treatment of congenital knee dislocation.

Congenital knee dislocation is a rare anomaly associated with a variety of neuromuscular diseases and deformities. The etiology of this condition remains unclear, but it is usually associated with a variety of disorders, such as Larsen's syndrome, arthrogryposis, spondyloepiphyseal dysplasia, Ehlers-Danlos syndrome, Down syndrome, and Streeter's dysplasia. It is rarely an isolated entity, and 60% of patients with congenital knee dislocation had additional congenital anomalies, most commonly hip dysplasia. The ideal method of treatment is debated. No current treatment algorithms address anterior cruciate ligament (ACL) elongation and its role in recurrent deformity or hyperextension. This article describes 2 patients who underwent open reduction of the knee for recurrent and neglected congenital knee dislocations. An ACL shortening and reinforcement technique is described. Both patients' treatment consisted of V-Y advancement of the extensor mechanism, soft tissue release, anterior capsulotomy, and posterior capsulorrhaphy. Anterior cruciate ligament shortening and reinforcement using an iliotibial band physeal-sparing technique was performed. The technique improved maintenance of reduction and prevented hyperextension of the knee. Anterior cruciate ligament elongation is an underemphasized anatomical feature associated with congenital knee dislocation. Due to its role in the prevention of anterior subluxation of the tibia and its effect on knee stability, incompetence should be addressed at the time of open reduction. The presence of an intact ACL with a congenital knee dislocation does not preclude management of anterior instability. Competence of the intact ACL should be addressed following reduction.