Arthroscopic diagnosis of the snapping popliteus tendon.

The syndrome of the snapping popliteus tendon is a rare cause of lateral knee pain and may be difficult to diagnose, leading to patients undergoing inappropriate therapy or surgical intervention. In this report, we describe the arthroscopic findings of the snapping popliteus tendon. Two men and 1 woman presented complaining of pain and a snapping sensation at the lateral aspect of the knee. No clear traumatic history was reported by any of the patients. Two patients had previously undergone partial lateral meniscectomy without relief of their symptoms. While the only consistently positive clinical sign was the Cabot sign, the arthroscopic findings confirmed the diagnosis in all cases. We observed in all cases inflammation around the tendon and visualized the portion of popliteus tendon near its insertion that is usually hidden by the femoral condyle. Further, flexion and extension with the limb in the tailor position revealed the snapping popliteus tendon. Successful treatment was achieved by securing the popliteus tendon to its sulcus on the lateral femoral condyle. Arthroscopic examination helps the surgeon to identify the snapping popliteus tendon to better treat this simple, yet oftentimes perplexing, condition.