Summary

CWDFO combined with medial reefing and lateral release successfully treated RPD with genu valgum for a minimum follow-up of 2 years, with improved patellar alignment and stability

Abstract

Background

Closing-wedge distal femoral osteotomy (CWDFO)—combined with medial reefing and lateral release, if necessary— has been used to treat recurrent patellar dislocation (RPD) with genu valgum.

Purpose

To evaluate the clinical and radiologic outcomes of surgical treatment with CWDFO for treatment of RPD with genu valgum.

Study Design:
Case series; Level of evidence, 4.

Methods

Fourteen consecutive patients (23 knees) with RPD and genu valgum were treated with CWDFO. Patients with a minimum 2-year follow-up period were eligible for this study. Patients with prior failed surgery were also eligible. Radiographic evaluation was performed with mechanical femorotibial and lateral distal femoral angle. The radiographic parameters presenting patellar positions and pathologic abnormalities associated with RPD were evaluated. Chondral lesion changes in second-look arthroscopic examination were examined, and clinical outcomes (eg, occurrence of redislocation, range of motion, and clinical scores) were assessed pre- and postoperatively at a minimum of 2 years.

Results

At a mean follow-up of 30.7 months (range, 25-62 months), the mean mechanical femorotibial and mechanical lateral distal femoral angles changed significantly from valgus 5° (range, 2°-11°) to varus 3° (2°-11°; P < .001) and from 83° (range, 78°-86°) to 89° (84°-92°; P < .001), respectively. The mean patellar congruence angle improved from 40° lateral (range, 20°-53° lateral) to 4° medial (23° medial to 21° lateral; P < .001), as did the lateral patellofemoral angle from 26° (range, 8°-62°) to 9° (0°-15°; P < .001). Computed tomography scans showed that the mean distance of patellar lateral shift decreased from 13.5 mm (range, 4-22 mm) to 2.0 mm (–4 to 5 mm; P < .001). The mean tibial tubercle to trochlear groove distance significantly decreased from 20.4 to 13.5 mm (P < .001), while the Caton-Deschamps ratio did not change significantly after surgery (P = .984). Chondral lesions of the patella and trochlear groove significantly improved or were maintained. None of the patients experienced subluxation or redislocation after surgery. Patellar instability symptoms also improved, as validated by radiographic and other clinical outcomes.

Conclusion

CWDFO combined with medial reefing and lateral release successfully treated RPD with genu valgum for a minimum follow-up of 2 years, with improved patellar alignment and stability.

Keywords
distal femoral osteotomy, medial reefing, patellar instability, tibial tuberosity