Patellar congenital dislocation of rare form

Three cases of the rare form of patellar congenital dislocation are presented. In the same patients their patella was dislocated during the knee flexion, and some time later dislocation can occur while extension during quadriceps sharp contraction. This form of dislocation is called by us intermediate. Three joints were operated. The roentgenological symptom is demonstrated, which characterizes this rare form of dislocation, as well as indications for surgical treatment and its performance. The reconstructive surgery was used, which reduced the probability of patellar dislocation for the knee flexion and extension. Good result was achieved in all cases.