Anatomical and functional study of the medial collateral ligament complex of the elbow

OBJECTIVE To carry out an anatomical study of the medial collateral ligament, an important elbow stabilizer in different degrees of elbow flexion-extension. METHODS Forty elbows were dissected in order to analyze the functional behavior of the anterior, posterior and transverse ligament bands during valgus stress maneuvers of the elbow in different degrees of flexion and extension. Two groups were determined; in the group GPA the posterior band of the ligament was sectioned initially, then the articular capsule and finally the anterior band; in group GAP this order was reversed. RESULTS Instability was observed in GPA only in the third stage, when there was a greater mean elbow's opening during the flexion (between 50° and 70°); in GAP, the instability was present since the first stage; the degrees of flexion with greater instability were the same as in group GPA. CONCLUSION The anterior band of the medial collateral ligament of the elbow is the most important stabilizer of the elbow valgus instability, and its principal action occurs between 50° and 70° of elbow flexion. Level of Evidence III, Diagnostic Studies - Investigating a diagnostic test.