Satisfactory midterm clinical results and low incidence of patellofemoral arthritis after MPFL reconstruction for patellar instability, in patients with low-grade trochlear dysplasia

Patella dislocation is among the most common knee pathologies in the young population. The anatomical structure getting injured in these cases is the medial patellofemoral ligament (MPFL), leading to patella instability. This study aims to evaluate the medium to long-term clinical results of our double-bundle technique for isolated MPFL reconstruction with hamstring autograft, mainly focusing on the incidence of subsequent patellofemoral arthritis. A retrospective analysis of 35 patients (39 patellae) with patella instability treated with isolated MPFL reconstruction surgery by the same orthopaedic surgeon between 2010 and 2020 was conducted. Patients were assessed using the following patient reported outcome measures: International Knee Documentation Committee (IKDC), Lysholm, Kujala and Modified Cincinnati, both pre and postoperatively. Additionally, the development of posttraumatic patellofemoral arthritis based on the Iwano classification was assessed by evaluating X-rays performed before surgery and at the final follow-up. The mean patients' age at the time of the first dislocation was 16.1 years (range, 10-21 years), and the mean age at the time of surgery was 20.3 years (range, 18-26). Females were 56,2% of the patients, and 43.8% were males; 75% of the injuries occurred during sport activities, while the rest after a direct hit. The mean follow-up was 7.3 years (5-13). All scores demonstrated significant melioration postoperatively. At the final follow-up, the IKDC score increased from 49.2 to 84.5, Lysholm from 53 to 88.2, Kujala from 61 to 88.5, and modified Cincinnati from 49.2 to 83.6. No immediate postoperative complication was reported, and no redislocation was recorded. Radiological evaluation indicated only mild signs of patellofemoral arthritis in eight patients (20%). The double-bundle technique for MPFL reconstruction with hamstring autograft is a safe and reliable option for treating patella dislocation in patients with low-grade trochlear dysplasia. It provides satisfactory outcomes without remarkable arthritic changes at a mid term follow-up. Level III.