Trochleoplasty and à-la-carte procedures for patellar instability in young and active patients: Clinical outcomes at minimum 2 Years follow-up

Introduction

Patellar instability is a common condition affecting approximately 6 individuals per 100,000, but among adolescents, this incidence is notably higher. Trochlear dysplasia has been recognized as the pathoanatomic risk factor exerting the most significant biomechanical influence. Over time, various surgical techniques have been developed to address trochlear dysplasia. The purpose of this study is to evaluate the clinical outcomes, return to sport, as well as complications and re-operation rate of sulcus deepening trochleoplasty performed in a cohort of young and active patients using the Bereiter technique.

Materials and methods

Between January 2019 and February 2022, 11 cases of recurrent patellar dislocations underwent trochleoplasty. Preoperative radiological assessment included X-rays, CT scans following the Lyons and MRI. Inclusion criteria for the study and trochleoplasty indications included patients aged 10–25 with recurrent patellar dislocations unresponsive to nonoperative treatment and minimum type B trochlear dysplasia. Clinical follow-up occurred at 1-3-6 months and annually, with control X-rays at these intervals. Patient-reported outcome scores included the Knee Society Score, Kujala score, and Karnofsky performance status scale.

Results

Between January 2019 and February 2022, 11 patients underwent trochleoplasty and were included in this study. Preoperative radiological measurements indicated mean values: sulcus angle (152.5°), trochlear depth (3.4 mm), Caton-Deschamps index (1.2), tibial tuberosity to trochlear groove (TT-TG) distance (17.5 mm), external patellar tilt angle (6.8°), femoral anteversion (11.5°), and tibial torsion (32°). All patients were followed up for at least 2 years, with an average of 43 months. Concurrent surgeries included tibial tuberosity transposition (100 %), MPFL reconstruction in 9 cases (81.8 %) and 2 patients also underwent division of the external alar ligament (18,2 %). PROMs at final follow-up showed mean values: Knee Society Score (KSS) (80.5), Kujala score (88.3), and Karnofsky performance status scale (88.8). Return to sport was reported by all active patients. Three cases required secondary surgical intervention for removal of the screws.

Conclusion

Trochleoplasty, especially with the Bereiter "thin flap" approach, improves patellofemoral congruency. Combining trochleoplasty with tibial tuberosity transposition addresses mal-tracking related to severe dysplasia and other à-la-carte procedures like medial patellofemoral ligament (MPFL) reconstruction enhance stability. In young and active patients, it resolves instability issues and reduces the likelihood of further dislocations with high return to sport rates.