Rate of progressive healing with a carbon-fiber orthosis in cases of partial union and nonunion after ankle arthrodesis using the Ilizarov external fixator

BACKGROUND: The Ilizarov fixator is a popular device for treating arthrodesis of the ankle joint in complex situations. However, the therapy can fail, with nonunion or partial union that might not be load stable. There is the possibility of follow-up surgery or extended wearing of the fixator. Full weight bearing with a carbon orthosis remains another treatment option, which has not yet been investigated.The aim of the study was to determine the rate of progress that can be obtained with a carbon orthosis in cases of partial union or nonunion after fixator removal. METHODS: In this retrospective observational study thirty-three patients received a carbon orthosis after fixator removal due to nonunion or partial union. All patients were allowed to walk with the orthosis under full load. The consolidation rate was determined radiologically and compared with the imaging data obtained during the last follow-up. In addition to demographic data, the Foot and Ankle Ability Measure and pain using a numeric rating scale were determined. Nine patients had to be excluded due to insufficient follow-up, and finally n = 24 patients were included in the study. RESULTS: The average duration of fixator use was 21 weeks (range 15–40 weeks), and the total average follow-up after removal of the fixator was 16 months (range 4- 56). For 14 (58.33%) patients, there was a further increase in consolidation with the orthosis after the fixator was removed. CONCLUSION: The results show that if there is only partial union or nonunion, further consolidations can be achieved after the application of a carbon orthosis. In a difficult patient population, using an orthosis should therefore be attempted to avoid unnecessary revision operations.