Treatment of patellar instability in adolescents is controversial. Some investigators have advocated early repair of the medial structures, whereas others have treated this injury nonoperatively. The medial patellofemoral ligament, is a primary restrictor and stabilizer of the patella, and has acquired a significant role in the treatment of instability in children and adolescents.

The authors present a prospective study of 39 consecutive patients (45 knees), without physeal closure, who underwent plasty of the medial patellofemoral ligament for the treatment of symptomatic patellofemoral instability with autologous Gracilis tendon, according to Chassaing’s technique. There were 26 female and 13 male patients with an average age of 15, 9 years. Mean follow-up was 44 months (6–65). All patients presented with clinical evident patellar tilt. This population presented a TA-GT within a normal range (12+/− 5 mm), but presented in 80% of cases a trochlear dysplasia

Clinical functional results were evaluated using the Kujala scale. Arthroscopic evaluation was systematically performed searching for intra articular injuries or patellar tilt. Early rehabilitation protocols were used in all cases.

At the last follow up evaluation, 90% of the patients presented good or very good results. Kujala Score was 84, 5 +/−9,7 after surgery compared with 54,9+/−11,8 before surgery (p< 0,0001). There were 3 minor complications: 2 hematomas and 1 superficial infection that resolved without complications.

Four patients kept complaining of residual anterior knee pain as result of patellar chondropathy that was diagnosed intra operatively. Three patients complained of graft donor site pain. One patient presented with a patellar dislocation three years after the surgery, and two patients still present clinical instability two years after the procedure. There was no stiffness in the knee in any patient.

The technique presented in this study has allowed very good clinical results, with few complications, using a small incision to reconstruct in an isometric fashion, this important patellar stabilizer.