Invasion of joints by primary bone sarcomas in adults.

In a retrospective macroscopic and microscopic study of celloidin-embedded macrosections from 45 adults with primary metaphyseal intraosseous sarcomas, we ascertained the incidence, extend, and mode of tumor extension into, across, or around articular cartilage into a joint. Invasion of articular cartilage by tumor occurred in more than one-third of the macrosections examined. In more than one-half of the cases, the sarcoma extended under the capsule insertion to involve the margin of the articular cartilage, thus leaving only a pseudocapsule between tumor and joint. Tumors frequently extended across or around the osseous-tendinous junction of the cruciate ligaments into the knee joint. Our findings have important implications for the surgical management of appendicular metaphyseal intraosseous sarcomas. For primary bone sarcomas, extraarticular resections should be considered seriously when limb salvage is contemplated, especially in the knee region.