Relationship of Ulnar Collateral Ligament Strain to Amount of Medial or Posterior Olecranon Osteotomy

Andrews JR, Heggland EJ, Fleisig GS, Zheng N.: Relationship of Ulnar Collateral Ligament Strain to Amount of Medial Olecranon Osteotomy. Am J Sports Med 29(6):716-721,2001

Levin, JS, Zheng, N, Dugas, J., Cain, EL and Andrews, JR: Posterior Olecranon Resection and Ulnar Collateral Ligament Strain, Journal of Shoulder and Elbow Surgery, Vol. 13, No. 1, Pages 66-71, January-February 2004

Valgus extension overload is a well-described entity in high-level throwing athletes. The same group of athletes who are at risk for tears of the anterior ulnar collateral ligament are also at risk for valgus extension overload. In two studies at ASMI, we investigated the effects of varying amounts of posteromedial olecranon osteotomy on ulnar collateral ligament stress in a cadaveric specimen.

Methods

In one study, five fresh-frozen human cadaveric elbows were dissected and mounted to allow strain gauge monitoring of the ulnar collateral ligament with varying valgus stress, elbow flexion angle, and medial osteotomy. In the second study, ten cadaveric arms underwent posterior olecranon resection in 4-mm increments. After each bone resection, three different valgus loads were applied to the elbow at 70 degrees and 90 degrees of flexion.

Results

In the first study, no statistically significant changes in strain were found for the different levels of osteotomy. The greatest differences in ulnar collateral ligament strain were seen when the elbow was flexed 50 degrees. The average strain to failure was 11.96% ą 6.51%, corresponding to a load of 347.71 ą 46.42 N. The maximum tensile force recorded at failure was 416.24 N.

In the other study, ulnar collateral ligament strain significantly increased with each load. Significantly more strain occurred on the ulnar collateral ligament at 90 degrees compared with 70 degrees of elbow flexion. This difference may be the result of the relative importance of the ulnar collateral ligament and the posterior olecranon at different position of elbow flexion.