A "sandwich" method of reconstruction of the medial patellofemoral ligament using a titanium interference screw for patellar instability in skeletally immature patients

No standard surgical procedure for medial patellofemoral ligament (MPFL) reconstruction exists in skeletally immature patients with patellar instability. This study aimed to evaluate the clinical effectiveness of a novel reconstruction technique for the MPFL in patients with patellar instability because of non-closure of the epiphyseal line. The "sandwich" method was fixation of the patella between a double-stranded semitendinosus tendon through the posterior third of the femoral insertion of the medial collateral ligament (MCL) as a pulley with a titanium interference screw in a single patellar tunnel. Five knees in five patients were studied: four with recurrent and one with habitual patellar dislocations. Subjects underwent MPFL reconstruction with or without lateral release. Patients were evaluated using pre-operative and post-operative physical and radiographic examinations, including apprehension testing, assessment of tilting and congruence angles, medial and lateral shift ratios under stress measured using X-ray imaging, and Kujala and Lysholm scores. No patient experienced recurrent post-operative episodes of dislocation or subluxation. By the final follow-up, patellar apprehension had disappeared in all patients. In addition, all patients showed significant improvement in the following: tilting angle, congruence angle, lateral shift ratio, Kujala score, and Lysholm score. The MPFL reconstruction methods, using a double-stranded semitendinosus autograft and sparing the femoral physeal line in non-closure of the epiphyseal line, provide acceptable short-term results for the treatment of patellar instability.