RESUMO
INTRODUCTION: A study conducted at our hospital showed that patellofemoral instability associated with a high-riding and lateralized patella occurred in 34 out of 4,954 admitted patients (6.86% rate). In order to treat these alterations we studied a series of patients in whom an anteromedialization technique was used. MATERIAL AND METHODS: This is a prospective, cross-sectional, descriptive cohort study, with probabilistic sampling, conducted between March 1st, 2009 and September 1st, 2011. Twenty patients who met the inclusion criteria were selected. The same technique was used in all patients, performed by the same surgeon, with the same postoperative and rehabilitation protocol. The modified Lyshom scale was applied and the results were assessed by two blinded observers whose concordance was assessed with the Kappa index. RESULTS: Twenty patients were treated, 12 females and 8 males; mean age was 20 years. In 14 patients the dislocating event occurred in one of the knees and in 6 patients it was bilateral; the right side predominated. Dislocation was recurrent in 7 patients and relapsing in 13; 12 of the latter had undergone soft tissue realignment and lateral retinaculum release, and one patellar advancement. The mean clinical Q angle was 18 degrees preoperatively and 7 degrees postoperatively. The preoperative and postoperative radio- graphic assessment was equivalent to a Kappa of 88%. Mean healing time of the osteotomy was 8 weeks; 2 hemarthroses occurred in the immediate postoperative period, which were resolved with puncture; no fractures and no graft collapses were reported. The mean Lysholm scale was 90.9 at 6 months (interobserver kappa of 90%). All patients had quadriceps atrophy of 1-2 cm, one patient had residual pain and by the end of the study none of the patients had had relapsing dislocation. CONCLUSIONS: This technique corrects the dislocation resulting from a high-riding and lateralized patella by modifying the Q angle. It involves minimal complications, uses a small 5 cm approach and does not require special guides. This study remains open to long-term follow-up to detect the presence or absence of patellofemoral arthrosis.