Journal of Hand Surgery

H. James Pfaeffle, Ph.D., Kenneth J. Fischer, Ph.D., Theodore T. Manson, M.S., Matthew M. Tomaino, M.D., Savio L-Y. Woo, Ph.D., D.Sc., James H. Herndon, M.D.


An improved understanding of forces acting in the forearm may help provide a scientific basis for reconstruction of the interosseous ligament in cases of longitudinal radioulnar dissociation. The objective of this study was to measure 3-D forces in the forearm when load is applied to the hand. 14 cadaveric forearms were loaded to 136 N of compression, while six-degree-of-freedom load cells measured forced vectors acting in the forearm. Computer forearm models were used to visualize force vector directions in 3-D. Results showed that the radius bears most of the load at the wrist while force in the interosseous ligament (IOL) acts to transfer load from the radius to the ulna. Force in the IOL displayed longitudinal and transverse components, suggesting that the IOL normally acts to provide longitudinal load transfer and transverse forearm stability. Transverse force exerted by the IOL pulls the radius and ulna together and results in transverse reaction forces at the distal and proximal radioulnar joints. In-situ in the IOL was highest in neutral rotation (31 N) and lowest in pronation (16 N). The IOL normally acts to relieve load on the radial head and provide stability to the radioulnar joints. In the setting of radial head arthroplasty for treatment of longitudinal radioulnar dissociation, reconstruction of the IOL may help stabilize the forearm and restore normal patterns of load transfer.