[The ankle joint in fibula malformations]

The ankle joints of 109 extremities with fibula reductions wer examined. The authors' findings led them to conclude that the shape of the ankle joint must be regarded as the result of an adaptation to altered functions. Ball-shaped ankle joints are frequently found in cases of hypoplasia of the fibula; partial and subtotal aplasias of the fibula are more likely to be associated with a valgus deformity of the ankle joint (known as Volkmann's ankle joint deformity) or, if more severe, with kyphosis of the tibia. If there is no laterodorsal restraint by coarse fibrous strands in cases of fibular aplasia, it is also possible that ball-shaped ankle joints will develop.