Fibular mobility in chronic lateral instability of the ankle

Using roentgen stereophotogrammetric analysis we recorded the mobility of the lateral malleolus under maximum passive plantarflexion and dorsiflexion and during the anterior drawer and the adduction tests in 29 patients with chronic lateral instability of the ankle. Medial and anterior displacements were observed during plantarflexion, at the adduction test and at the posterior loading of the tibia. At dorsiflexion we recorded posterior fibular shifts. The simultaneously occurring fibular rotations were small. Chronic lateral instability of the ankle was associated with slightly increased fibular movements during plantarflexion and dorsiflexion, and at the adduction test in some patients with bilateral symptoms, perhaps reflecting a generalized joint laxity.