Combined supracondylar femoral derotation osteotomy and patellofemoral ligament reconstruction for recurrent patellar dislocation and severe femoral anteversion syndrome: surgical technique and clinical outcome

Abstract

Purpose: Severly increased femoral anteversion is an important risk factor for patellofemoral instability. Recurrent dislocations cause a traumatic disruption of the medial patellofemoral ligament. Therefore a procedure that combines femoral derotation osteotomy and patellofemoral ligament reconstruction should be considered for patients with severely increased femoral anteversion. The aim of the study was to evaluate the subjective and objective outcomes after combined femoral derotation osteotomy and anatomical reconstruction of the MPFL.

Methods: 12 consecutive patients (12 knees) with patellofemoral instability and severely increased femoral anteversion underwent combined femoral derotation osteotomy and anatomical reconstruction of the MPFL. Preoperative radiographic examination included AP and lateral views to assess patella alta. MRI was performed to evaluate trochlear dysplasia and tibial tubercle-trochlear groove (TT-TG) distance. Additionally, MRI assessment of the rotational profile was performed. Evaluation included evaluation of cartilage injuries, preoperative and postoperative physical examination, visual analog scale (VAS), Kujala score, International Knee Documentation Committee score (IKDC), Activity Rating Scale (ARS) and Tegner activity score.

Results: The average age at the time of operation was 18.2 years (range, 15-26 years). The average follow-up after operation was 16.4 months postoperatively (range, 12-28 months). No recurrent dislocation occurred. The results showed a significant improvement of the Kujala score, IKDC score and VAS (p < 0.01). The activity level according to the Tegner activity score and ARS did not show statistically significant changes (p = 0.75; p = 1.0).

Conclusion: Combined anatomical reconstruction of the MPFL and femoral derotation osteotomy resulted in significant improvement of knee function and good patient satisfaction in young patients with severely increased femoral anteversion. No re-dislocation of the patella occured.

Keywords: Increased femoral anteversion; Knee; MPFL; Patellar dislocation; Patellofemoral instability.