Osteophyte impingement of the popliteus tendon as a cause of lateral knee joint pain.

Three cases of symptomatic popliteus tendon impingement on an osteophyte are presented. In only one case did the patient complain of a painful 'snapping' on flexing and extending the knee. Diagnosis was made when tenderness was elicited on palpating the osteophyte during flexion and extension with varus stress on the knee. It may be difficult to determine whether such a prominence represents an osteophyte or an exaggerated normal lower border of the popliteus groove. Two cases were successfully treated by arthroscopic excision of the osteophyte and the remaining case by resection of the popliteus tendon.