[Muscular stabilization of the upper ankle joint in lateral instability. An experimental study].

The mechanical stabilizing effect of artificially applied muscular strength to the peroneal tendons was examined in an experimental study using cadaveric lower legs with unstable ankle joints. Therefore the anterior fibulo-talar and the fibulo-calcanear ligament was dissected and the resulting instability with examination of the anterior drawer sign and the talar tilt was measured under standardized conditions. After initial measurement under standardized conditions a muscular strength of 75 N and 150 N was applied and the resulting stability was measured again. In a second experiment an additional orthotic device was applied and the stability was measured again under applied muscular strength. The results demonstrated that stable conditions at the lateral unstable ankle joint are only achievable when a muscular strength of 75 N (ant. drawer sign) or 150 N (talar tilt) is combined with the application of an orthotic device. For clinical treatment this means that functional treatment for ankle sprains with application of an orthotic device needs additional training for improvement of the muscular strength of the peroneal muscles.