Role of the forearm interosseous ligament: Is it more than lust longitudinal load transfer?

The objective of our study was to measure 3-dimensional force vectors (magn itude and direction) acting in the forearm when load is applied to the hand and to measure the actual force in the interosseous ligament (IOL). Fourte en cadaveric forearms were loaded to 136 N of compression while special loa d cells measured force vectors in the forearm. Computer forearm models were used to display the 3-dimensional force vector directions. The study resul ts showed that the radius bears most of the toad at the wrist but load on t he radius at the elbow is reduced because the IOL transfers load to the uln a between the wrist and the elbow. In addition to this role in longitudinal load transfer, our measurement of 3-dimensional forces allowed identificat ion of transverse vectors which suggest that the IOL also functions to keep the radius and ulna from splaying apart. Our results imply that the IOL pa rticipates not only in longitudinal load transfer but also in the maintenan ce of transverse stability of the forearm during compressive load transfer from the hand to the elbow. (J Hand Surg 2000;25A: 683-688. Copyright (C) 2 000 by the American Society for Surgery of the Hand).