Congenital dislocation of the knee. Its pathologic features and treatment.

Arthrograms and operative findings of 19 patients with 26 congenital dislocations of the knee (CDK) were reviewed to clarify the pathologic features, methods of treatment, and the optimum treatment for the patient with multiple joint deformities. The fundamental pathologic features in CDK involved a shortening of the quadriceps femoris tendon, a tight anterior articular capsule, and hypoplasia of the suprapatellar bursa. Valgus deformity of the knee, which was observed in half of the patients, was caused by the fragility of the medial components of the knee. This fragility was attributable to the forward displacement of the tibial insertion of the medial components. Arthrograms served as effective indicators when evaluating the pathologic features and determining the applicability of surgical therapy. There were limits to conservative therapy that were dependent on the extent of the pathologic changes. In extremely refractory patients with arthrogryposis multiplex congenita (AMC), an elimination of genu recurvatum and an improved range of movement could be obtained by the use of surgery. The valgus deformity was significantly reduced by invasive treatment that reinforced the fragile inner components. Experience with nine patients with multiple lower-limb joint deformities indicates that the knee dislocation should be treated before any of the other deformities.