The role of the interosseous membrane on tibiofibular weightbearing.

Three in vitro, strain gauge instrumented lower legs were loaded in positions ranging from 10 degrees dorsiflexion to 10 degrees plantarflexion with loads corresponding to those seen in normal gait. The interosseous membrane was found to play a critical role in the load-sharing ability of the fibula. After incision of the membrane, fibular strains decreased to essentially zero, thus supporting the hypothesis that the interosseous membrane acts as a conduit for stress transmission to the fibula. An intact membrane keeps the fibula active during the loads and motions of normal gait.