Elbow Ligaments Hold Tight, Despite Heavy Strains of Athletics

Keep bending a green twig back and forth, and it will eventually break. Keep pitching fast balls at 90 mph, and the shoulder joint will soon become stretched and loose. But what about the elbow joint? Do the ligaments that support the elbow loosen with the repeated elbow strains common to athletes?

A recent study calls into question popular opinion. Until now, it was generally believed that stability in the elbow joint was much like that of the shoulder. Repeated actions in the shoulder tend to cause the shoulder to loosen and become painful over the years, a condition called laxity. Researchers questioned whether players without elbow pain tend to show signs of greater laxity in the elbow joint.

This study compared the elbows of 136 male college athletes. More than one-third played sports that required overhand actions, such as baseball and tennis. The other participants did sports in which the shoulder and elbow were not routinely used in overhand actions, sports such as wrestling and track.

Each athlete had both his elbows tested in a device that pushed against the forearm, angling the elbow outward. This test was used to see how well the ulnar collateral ligament on the inside edge of the elbow held under pressure. Applying stress to a joint causes it to "open" or separate slightly. Healthy ligaments prevent joints from opening too far. The doctor then took an X-ray to tell if the joint had become lax by measuring the separation when stress was applied.

There were no major differences between players, even those doing overhand sports and those who had been playing for many years. Nor was there much difference between each players' dominant and nondominant elbows. (The dominant elbow is the one on the arm most frequently used--the right elbow on a right-handed person.) Surprisingly, over half the players' nondominant elbow joints had equal or greater laxity than their dominant elbow joints. These findings led the authors to conclude that extra laxity of the elbow doesn't occur in athletes who are free of elbow pain.

This is likely because the elbow joint fits together so snugly that the joint is generally stable. This bony stability helps protect the ulnar collateral ligament. However, it also makes it challenging for scientists to specify a cut-off measurement that lets doctors know when a player has developed a loose ulnar collateral ligament.

References: Hardayal Singh, MD, et al. Valgus Laxity of the Ulnar Collateral Ligament of the Elbow in Collegiate Athletes. In The American Journal of Sports Medicine. September/October 2001. Vol. 29. No. 5. Pp. 558-561.