Management of Failed Ankle Fusion and Avascular Necrosis of the Talus with a Vascularized Fibular Graft

In cases of failed ankle fusion, it is also very difficult to achieve a solid talo-tibial fusion with conventional methods. Nonunion of talus fracture associated with avascular necrosis of the talus is a difficult problem in extremity reconstruction. Many modalities (techniques) have been introduced for the treatment of avascular necrosis of the talus and failed ankle fusion. The results of core decompression or conventional bone-grafting techniques used in treating avascular necrosis of the talus have been unpredictable. It can be expected that living bone inserted into the necrotic talus can promote bone circulation and new bone formation around the nonunited fracture site.

The authors applied free vascularized fibular grafts in 3 cases of avascular necrosis of the talus combined with non-union. The average follow-up period was 14 months. There were also 4 cases of failed ankle fusion managed with free vascularized fibular grafts.

In the avascualr necrosis of the talus procedure, the whole fibula with surrounding muscle sleeve and vascular pedicle is too big for a living bone graft in the small talus. The authors used sagittal split vascularized fibular transplantation based on periosteal circulation of the fibula.

Results of that procedure were encouraging. During an average 5.5 years follow-up period, the nonunited portion achieved bone union, and symptoms such as diminished tenderness and pain-free weight-bearing improved. Radiologic findings showed gradual diminishing of sclerosis of the talar dome, which is suggested for improving avascular necrosis of the bone. The average range of the ankle joint was 45% of the normal side. There was moderated pain during weight-bearing, which was diminished over the longer follow-up. Three of the 4 cases of failed ankle fusion achieved solid fusion with free vascularized fibular transfer.

The authors proposed vascularized fibular grafting as one of the better alternatives for treating avascular necrosis of the talus and managing failed ankle fusion. It is expected that vascularized fibular grafting can prevent the necrotic talar dome from progressing to collapse, and can promote directly restored vascularization and new bone formation.