A symptomatic cyamella in the popliteus tendon causing snapping knee: a case report and literature review

Background Cyamella,the sesamoid bones of the popliteus muscle, are rare in humans. Snapping knee is an uncommon problem which can be difficult to diagnose. Case presentation In this case, we report a 24-year-old male with snapping knee caused by symptomatic cyamella in the popliteus tendon. A large cyamella was identified upon surgery and was removed. Postoperatively, the patient had immediate relief of preoperative symptoms, and there were no signs of recurrence after 1 years of follow-up. Conclusions Although not previously suggested, symptomatic cyamella in the popliteus tendon should be considered as part of the differential diagnosis of the snapping knee.