Optimal attachment site for reconstruction of the ulnar collateral ligament. A cadaver study.

To determine the isometric points for ulnar collateral ligament (UCL) reconstruction, we performed a kinematic study of 15 cadaver elbows. The margins of the anterior and posterior oblique ligaments of the UCL were measured. Five humeral and three ulnar attachment sites were also selected and grouped in pairs for measurement. The distances from the proximal center of the trochlea to three ulnar points were recorded. Measurements were obtained for pairs of attachment sites for flexion of 0 degree, 30 degrees, 60 degrees, 90 degrees, and 120 degrees. We found that the anterior margin of the anterior oblique ligament (AOL) tended to lengthen as flexion increased from 0 degree to 60 degrees, and to shorten as flexion exceeded 60 degrees. The posterior margin tended to lengthen with flexion up to 120 degrees. It therefore appears that the AOL consists of functionally different components that remain taut throughout flexion. In all experiments, the location of the humeral attachment site affected the lengths through 120 degrees of flexion. At flexion of 0 degree-120 degrees, isometricity was observed in the approximate center of the trochlea, apparently the optimal attachment site. We conclude that conventional ligament reconstruction methods that locate the attachment site in the AOL origin provide inadequately for the isometricity observed in the natural anatomy.