Posterior compartment syndrome resulting from a dissecting popliteal cyst. Case report.

Calf swelling, associated with an intra-articular effusion of the knee, should be considered a dissecting popliteal cyst until proven otherwise. The posterior compartment syndrome caused by an increase in pressure within the deep posterior compartment of the leg is usually secondary to trauma. This case history of a dissecting popliteal cyst reports another unusual cause of the posterior compartment syndrome. Popliteal cysts, especially dissecting ones, are typical of connective tissue diseases, and are not limited to rheumatoid arthritis.