Arthroscopic reconstruction of the medial patellofemoral ligament in skeletally immature patients using the modified sling procedure: a novel technique for MPFL reconstruction

Background Patellar dislocation is common in young people. Although isolated anatomic double-bundle reconstruction of the MPFL is a common and effective surgical treatment for patellofemoral instability, concerns about the risk of injury to the epiphysis remain. Methods A total of 21 children and adolescents (9 males, 12 females; mean age: 10.7 years; range: 8 to 13 years) with recurrent patella dislocation or symptomatic instability following a primary dislocation were enrolled in the study. In all patients, double-bundle medial patellofemoral ligament (MPFL) reconstruction and femoral sling procedure were performed under arthroscopy, using an anterior half peroneus longus tendon (AHPLT) autograft. Functional outcomes were evaluated preoperatively and during follow-ups based on Kujala and Lysholm scores. Radiological examinations including radiographs, 3D-CT, and MRI were performed pre- and post-operatively. Results Among two-year postoperative follow-up (range: 24–42 months) showed significant improvement in functional scores ( p < 0.01). The Lysholm score increased from 68 (44.5) to 100 (0) and the Kujala score increased from 26 (34.5) to 100 (2) The patellar tilt angel improved significantly ( p < 0.01) from 24.3° ± 10.4 preoperatively to 11.9° ± 7.0 postoperatively. MRIs performed 6- and 12-months post operation did not show any signs of dysfunction of the reconstructed MPFL or cartilage degeneration. Study design Case Series; Level of evidence, 4. Conclusion Arthroscopic reconstruction of the MPFL using the modified sling procedure is an effective procedure for the treatment of patellar instability in skeletally immature patients.