Surface EMG Evaluation of Patellofemoral Pain Syndrome in a Professional Ballet Dancer : A Case Report

Objective: Because of the repetitive loading of the lower limb, patellar disorders are common in athletes and performing artists. Although this condition might be ascribed to different factors, the main cause is believed to be patellar maltracking. Design: Patellar maltracking is believed to be generated by an asymmetric activation of the vastus lateralis and vastus medialis obliquus muscles. A professional ballet dancer who suffered from anterior knee pain was examined. After clinical and MRI evaluations, he was subjected to surface electromyography (sEMG) of the vastus medialis obliquus and vastus lateralis. Results: We found a difference in the latency of onset of the vastus medialis obliquus and vastus lateralis of the painful right knee as compared to the asymptomatic left knee. Conclusion: Via sEMG, we demonstrate the role of the vastus medialis in patellar maltracking. sEMG is therefore a useful method to help diagnose and guide treatment in performing artists and elite athletes