Functional anatomy of the medial ligamentous complex of the elbow. Its role in anterior posterior instability.

The question remains unanswered regarding the role of repair of medial ligament injuries associated with subluxation of the elbow and non-reconstructable radial head fracture and whether or not this will decrease the risk of chronic instability and cubitus valgus. The goal of this study was to define the role of the medial ligamentous complex of the elbow in elbow instability and to describe the anatomy of the complex in 35 fresh-frozen cadaver elbows. We documented medial ligamentous complex anatomy and compared our results to those in the literature. 25 elbows were dissected in order to describe the different bundles of the medial ligament complex and to precise the positions of the elbow that placed each in tension; section of the different ligamentous bundles was done to study the role of each in elbow stability. 10 other elbows were dissected and used for the ligamentous section studies which were performed subcutaneously. We found two bundles at the level of the anterior portion and termed them superficial and deep. Section of the anterior bundle lead to posterior subluxation of the elbow at 30-100 degrees flexion in both supination and pronation. Posterior subluxation was obtained after an anterior capsulotomy; medial epicondylectomy did not compromise the stability of the elbow after a complete section of the insertion of the deep fibers of the anterior bundle. Elements thus required for stability of the elbow are integrity of the articular surface of the humerus and the ulna, and the anterior bundle of the medial ligamentous complex.