Origin of the medial ulnar collateral ligament.

The anatomic features of the origin of the anterior medial collateral ligament of the elbow were studied in 10 cadaver elbows to determine the percentage of the medial epicondyle that can be removed without violating the ligament, and whether or not this ligament attaches to the condyle as well as to the epicondyle. In all specimens the anterior medial collateral ligament originated exclusively from the anteroinferior surface of medial epicondyle and had no attachment to the condyle. Only 20% of the width of the medial epicondyle in the coronal plane can be removed without violating a portion of the origin of the anterior medial collateral ligament, an essential stabilizer of the elbow. Excision of the entire epicondyle for ulnar neuropathy would completely detach this ligament from its origin and might therefore potentiate instability. Since the ligament originates on the anteroinferior surface of the epicondyle, more bone can be removed with less violation of the anterior medial collateral ligament origin if the plane of the osteotomy lies between the sagittal and coronal planes.