Giant osteochondral body in a popliteal cyst

Abstract

Popliteal cysts, although commonly seen, are rarely associated with motion restriction or calcification. Radiological features are of soft-tissue swelling, with occasional reports of calcifications or small osteochondral bodies inside the cysts. We report a giant osteochondral body in a popliteal cyst, with significant mechanical block to flexion. This type of mass has to be differentiated from synovial osteochondromatosis, calcifications in the cyst, extraosseous and intraarticular osteochondromas. Complete excision of the cyst resulted in complete recovery of range of motion.

Bursae around the knee joints

“…[10] It may or may not communicate with the knee joint. It may rupture and extend inferiorly along the gastrocnemius muscle into the calf or extend superiorly into thigh along the semimembranosus.…”

“…It is commonly confused with a popliteal cyst; the pes anserine bursa is located posteriorly and medially along the semitendinosus, whereas the popliteal cyst is located more often in the midline posteriorly. [ 10 ] Also, pes anserine bursae are small in size; they do not extend into the thigh and never show communication with the knee joint,[ 11 ] whereas a popliteal cyst can extend into the thigh and may or may not communicate with the knee joint.…”

“…This is also called a popliteal cyst and typically involves the gastrocnemius- semimembranosus bursa and is located between the medial femoral condyle, semimembranosus tendon and the medial head of the gastrocnemius. [ 10 ] It may or may not communicate with the knee joint. It may rupture and extend inferiorly along the gastrocnemius muscle into the calf or extend superiorly into thigh along the semimembranosus.…”