Optimizing the rehabilitation of elbow lateral collateral ligament injuries: a biomechanical study.

BACKGROUND Elbow lateral collateral ligament (LCL) injury may arise after trauma or lateral surgical approaches. The optimal method of rehabilitating the LCL-insufficient elbow is unclear. Therapists often prescribe active motion exercises with the forearm pronated. Recently, overhead exercises have become popular as they may enable gravity to compress the elbow joint, improving stability, although this has not been proved biomechanically. This investigation aimed to quantify the effects of several variables used in LCL injury rehabilitation on elbow stability. METHODS Seven cadaveric specimens were tested in a custom elbow motion simulator in 3 arm positions (overhead, dependent, and varus) and 2 forearm positions (pronation and supination) during passive and simulated active elbow extension. Three injury patterns were studied (intact, LCL injury, and LCL with common extensor origin injury). An electromagnetic tracking device measured ulnohumeral kinematics. RESULTS Following combined LCL and common extensor origin injury, overhead positioning enhanced elbow stability relative to the other arm positions (P < .01 in pronation; P = .04 in supination). Active motion stabilized the LCL-deficient elbow in the dependent (P = .02) and varus (P < .01) positions. Pronation improved stability in the overhead (P = .05), dependent (P = .06), and varus (P < .01) positions. CONCLUSIONS Rehabilitation with the arm overhead improves elbow stability after LCL injury. Initiating earlier range of motion in this "safe position" might decrease elbow stiffness and allow optimal ligament healing. If exercises are done in the dependent position, active motion with forearm pronation should be encouraged. Varus arm positioning should be avoided.