Semimembranosus tendinitis: an overlooked cause of medial knee pain.

A significant number of patients presenting with nontraumatic chronic medial knee pain have been found, after careful examination, to have chronic semimembranosus tendinitis. Of 115 patients diagnosed and treated for semimembranosus tendinitis over a 5 year period, 10 patients were refractory to conservative treatment. The purpose of this paper is to discuss the symptomatology and diagnosis of semi-membranous tendinitis, and to relate the treatment that these 10 patients underwent, i.e., surgical exploration, drilling of the insertion site, and semitendinosus tendon transfer. Most cases of semitendinosus tendinitis respond to conservative therapy; however, if surgical treatment is considered, arthroscopy should probably be performed at the time of surgery. In this way, it is possible to determine the presence of significant intraarticular abnormalities that may have a causal relationship with the onset of semimembranosus tendinitis.