Congenital dislocation of the patella is a dislocation of the knee cap, usually associated with rotatory subluxation (partial dislocation) of the tibia on the femur, with internal femoral torsion and with flexion contracture of the knee. The condition may be present at birth or it may develop shortly afterwards. If left untreated, arthritis of the knee will develop. The flexion contracture of the knee makes the limb appear shorter than the other side. The condition can be unilateral (one side) or bilateral (both sides).
In this condition, the tibia rotates externally on the femur, dragging the patellar tendon and therefore the patella with it. The tibia is stuck in a rotated position and as such neither the tibia or the patella can reduce or stay reduced. The iliotibial band is very tight and pulls the tibia into this position. With the tibia in this rotated position the knee often does not go fully straight and has a flexion contracture. The biceps (hamstring muscle) is therefore tight and also pulls the tibia into the rotated flexed position.
Diagnosis for congenital dislocation of the patella is generally not made until the patient is at a walking age. The condition is quite rare. Nonoperative treatments are not recommended since the condition can seriously impair long-term function. Dr. Paley invented a surgical procedure to comprehensively address the orthopedic difficulties of congenital dislocation of the patella. The surgery is called the SUPERknee and was developed by Dr. Paley in 1994. SUPER is an acronym for Systematic Utilitarian Procedure for Extremity Reconstruction. It is a combination of two older procedures: Langenskiold and Grammont. The final result after surgery is a knee that is fully straight, a stable and functional patella that is relocated to the front of the knee, and a strong quadriceps muscle.