Posterolateral rotatory instability of the elbow with insufficient coronoid process of the ulna: a report of 3 patients.

Congruity of the ulnohumeral joint, especially its anterior portion, is an important stabilizer of the elbow joint. We report on 3 patients in whom the insufficiency of the coronoid process, such as nonunion or a flattened trochlear notch, was associated with posterolateral rotatory instability of the elbow. In our opinion, addressing the anterior bony integrity of the ulnohumeral joint, in addition to the ligamentous stabilizer and mechanical axis, is essential to achieve stability in these circumstances. This issue is discussed with a review of the literature.