Relative shortening of the fibula may occur after any type of ankle fracture when the lateral malleolus is involved. Patients complain of pain and restriction of their daily and sporting activities. Clinically, there is valgus of the hind foot due to abduction and lateral rotation of the talus. The goal of treatment is to restore the initial length of the fibula by a horizontal or Z-osteotomy, which will also correct the malposition of the talus. This study shows that the operative reconstruction of a widened mortise is a relatively safe procedure, independent of the type of osteotomy used. Lengthening of the fibula is an important step in the treatment of the painful ankle when the fibula is short after trauma, even when degenerative changes of the joint are already present.