Comparable postoperative outcomes in patients treated with either open or arthroscopic trochleoplasty for patella dysplasia

Background: The aim of this study was to compare the clinical and radiologic results of the arthroscopic and the open trochleoplasty techniques.

Methods: A total of 83 trochleoplasties in 83 patients were performed between 2014 and 2021 in one institution. Surgical indications for trochleoplasty were recurrent patellofemoral instability and a lateral trochlear inclination angle (LTI) ≤ 11˚ and a trochlear depth ≤ 6 mm. Of the trochleoplasties, 40 were done by open technique (OT) and 43 by arthroscopic technique (AT). In every case an additional medial patellofemoral ligament (MPFL) reconstruction was performed. Additional tuberosity tibia transfer and/or de-rotation of the femur were done when indicated. Pre- and postoperative magnetic resonance imaging (MRI) were analyzed in respect to LTI, trochlear depth, and lateralization of the patella. Postoperative subjective clinical assessment was done using the Kujala Score, Banff II Score, Tegner Score, and Marx Score.

Results: Of the patients, 15 with OT and 20 with AT were available for follow-up. The mean follow-up was 29.9 months in the OT group and 12.7 months in the AT group. No re-dislocation was observed in either groups. A significant reduction of LTI, increase of trochlear depth, and a reduction of lateralization of the patella was observed between the pre- and postoperative MRI scans in both groups. No significant difference in the observed MRI parameters was found between the two groups. Neither was there a difference in the postoperative Kujala Score, Banff II Score, Tegner Score, and Marx Score between the two groups. Length of stay was on average 6.2 days in the AT group and 8.1 days in the OT group. The surgical time was on average 141 min in the OT group and 160 min in the AT group.

Conclusion: We found that patients undergoing an arthroscopic trochleoplasty had a comparable outcome with respect to clinical and radiological parameters compared with patients treated by open trochleoplasty.