A surgical algorithm for the treatment of recurrent patellar dislocation. Results at 5 year follow-up.

Several options exist for the treatment of recurrent patellar dislocation. In our institution a specific treatment algorithm for patellofemoral maltracking, depending on skeletal maturity and the recognition of local risk factors has been in use for several years. The aim of our study was to evaluate the overall results of using this algorithm and to compare the outcome of the different subgroups. A total of 110 patients were studied with an average follow-up of 53 years. The patients were classified into 6 groups depending on the surgical treatment they had received. Eighty-seven percent of patients remained free of dislocation at final follow-up, and 66% of patients no longer experienced any patellar instability or subluxation. There was no statistically significant difference between skeletally mature and immature patients in the incidence of redislocation or recurrent instability, nor in functional or clinical outcome scores. Skeletally immature patients who underwent isolated medial retinacular imbrication experienced the highest redislocation rate (29%), whereas skeletally mature patients who were treated with combined proximal and distal realignment procedures demonstrated the lowest redislocation rate (6%). Skeletally mature patients with combined proximal and distal procedures reached lower clinical and functional outcome scores. Based upon the results from this study we believe that our surgical algorithm can serve as a model for the treatment of recurrent patellofemoral dislocation.