Kinematics of partial and total ruptures of the medial collateral ligamentof the elbow

In this study the kinematics of partial and total ruptures of the medial co llateral ligament of the elbow ore investigated. After selective transectio n of the medial collateral ligament of 8 osteoligamentous intact elbow prep arations wets performed, 3-dimensional measurements of angular displacement , increase in medial joint opening, and translation of the radial head were examined during application of relevant stress. Increase in joint opening was significant only after complete transection of the anterior part of the medial collateral ligament was performed. The joint opening was detected d uring valgus and internal rotatory stress only. After partial transection o f the anterior bundle of the medial collateral ligament was performed, ther e was an elbow laxity to valgus and internal rotatory force, which became s ignificant after transection of 100% of the anterior bundle of the medial c ollateral ligament and was maximum between 70 degrees to 90 degrees of flex ion. No radial head movement was seen after partial or total transection of the anterior bundle of the medial collateral ligament was performed. In co nclusion, this study indicates that valgus or internal rotatory elbow insta bility should be evaluated at 70 degrees to 90 degrees of flexion. Detectio n of partial ruptures in the anterior bundle of the medial collateral ligam ent based on medial joint opening and increased valgus movement is impossib le.