Monofocal distraction treatment of stiff aseptic tibial nonunions with hexapod circular external fixation

Background: Tibial nonunions remain a significant and challenging clinical problem. Nonunions occur due to a failure of biology, a failure of biomechanics, or both. The cells in and around the nonunion site have an osteogenic potential that can be activated when torsional, axial, and shearing instabilities are eliminated by establishment of an appropriate biomechanical milieu. Hexapod external fixators may be able to provide this milieu. Materials and Methods: In this retrospective study, consecutive patients with tibial nonunions treated in a single center were analyzed. They were all treated by the application of a hexapod circular fixator before deformity correction and distraction. This was followed by functional rehabilitation. We determined general health status with the use of the Short Form 12 measurement tool. Results: A total of 32 patients with 33 stiff hypertrophic nonunions were treated with circular fixators. The average age was 44 years, there were 24 males and 8 females. Out of the 33 nonunion cases, 29 united with closed distraction only; 3 required bone graft and 1 underwent amputation. The average time to union was 170 days. Overall on the final examination, all patients had a health status that was similar to the general population norm. Conclusion: A success rate in excess of 80% can be achieved with mechano-biological manipulation using hexapod external fixation in tibial nonunions without bone grafting.