A novel technique for reconstruction of the medial patellofemoral ligament in skeletally immature patients.

Habitual or recurrent dislocation of the patella in the skeletally immature patient is a particularly demanding problem since the etiology is frequently multifactorial. The surgical techniques successfully performed in adults with patellar instability may risk injury to an open growth plate if applied to children. We present a technique that preserves femoral and patellar insertion anatomy of medial patellofemoral ligament (MPFL) using a free semitendinosus autograft together with tenodesis to the adductor magnus tendon without damaging open physis on the patellar attachment of MPFL. A 3-cm long longitudinal skin incision is performed 10 mm distal to the tibial tuberosity on the anteromedial side. The semitendinosus tendon is harvested with the stripper. The semitendinosus tendon is placed on a preparation board and cleaned of muscle tissue. The usable part of the tendon should be at least 20 cm long and 4 mm wide. The two free ends of the graft are sutured with Krakow technique. A medial longitudinal incision 2 cm in length is made to expose the MPFL and to abrade the patellar attachment of vastus medialis obliquus. The first patellar tunnel is created with 4.5 mm drill at the mid aspect of the medial patella in the anteroposterior and proximal-distal direction. The drill hole is formed parallel to the articular surface of the center of the patella. The second tunnel is created with 3.2 mm drill and the entry point is localized at the center of the patella. These two tunnels intersect to form a single tunnel. The semitendinosus autograft is run through the bone tunnel in the patella. Double-stranded semitendinosus autograft is placed in the presynovial fatty plane between the second and the third layer of the medial retinaculum, and tenodesis to adductor magnus tendon is applied by a moderate medial force with the knee flexed at 30°. Aftercare includes immobilization of the joint limited to 30° flexion using an above-knee splint for 2 weeks. No recurrent dislocation was observed in three patients (4 knees) at a mean follow-up time of 17.7 months. Both range of motion and radiological finding were restored to normal limits.