Semimembranosus tendon viewed through an isolated medial meniscus capsular avulsion: a case report.

The semimembranosus is a key component of the complex anatomy of the posteromedial knee. Its multiple distal insertions are intimately associated with the posterior capsule, medial meniscus, and posterior oblique ligament. Visualization of the semimembranosus is possible during arthroscopy when a significant posteromedial capsular injury is present. This typically occurs only in the setting of significant trauma, with associated injury to the other posteromedial knee structures. We present a case of an isolated medial meniscus capsular avulsion, with minimal trauma, in which the semimembranosus tendon is clearly visualized during arthroscopic meniscal repair.