TREATMENT OF CONGENITAL DISLOCATION OF THE PATELLA

Congenital dislocation of the patella requires early surgical reduction for better walking. We studied the results of our combined soft tissue procedures performed on 6 knees in 5 children. The age at surgery ranged from 3 to 12 years with a mean of 5.3 years. The follow-up period ranged from 3 to 9 years with a mean of 5.1 years. Underlying diagnoses were fibular hemimelia in one knee, congenital dislocation of the knee which was reduced without surgery in two, and nail-patella syndrome in three. The surgical procedures involve lateral release to reduce the patella, resection and tightening of medial capsule and semitendinosus transfer to the patella. Quadriceps lengthening was also required in two knees. After lateral release, the semitendinosus tendon is detached at its insertion, and is pulled out at the musculotendinous junction. Then, the tendon is pulled down to the patella under the skin, and is passed through a drilled tunnel in the patella from superomedially to inferolaterally. Finally, the tendon is reflected and sutured to the anterior surface of the patella under sufficient tension at 20 degrees of knee flexion. The five knees operated on under 5 years of age were well reduced and well positioned in the femoral groove at follow-up. The one knee operated on at the age of 12 years showed subluxation. Episodes of giving way and abnormal gait disappeared after surgery in all the patients. Femoral groove depth increased after surgery. The improvement in the young infants was better than in older child. We found that the transferred semitendinosus tendon acts well to maintain good patellar position during knee flexion. We conclude that early surgical reduction is extremely important and it will stimulate proper development of femoral groove, and semitendinosus transfer combined with lateral release is effective to keep the patella in its groove during knee flexion.