Mechanical solutions to salvage failed distraction osteogenesis in large bone defect management.

INTRODUCTION: Ilizarov bone transport for large bone defect is challenging and may end in distraction osteogenesis failure.

MATERIAL AND METHODS: Ten forearm and seven tibial defect cases with failed regeneration due to ischaemia during bone transport were studied retrospectively. Mean forearm and tibial defects were 5.5 ± 0.8 and 7.6 ± 1 cm respectively, or 22.3 ± 3.6 and 20 ± 2.3% as compared with healthy segments. Most patients had numerous previous operations (2.6 ± 0.5 and 3.4 ± 0.8 per patient, respectively), extensive scars locally and post-traumatic neuropathy. There were seven infected defects. Mechanical solutions used were (1) additional osteotomy and transport of the fragment to compact the ischaemic regenerate (10 forearms, 4 tibias) and (2) compaction of the connective tissue layer in the tibial regenerate with either two 5-mm steps (two cases) or gradually (one case).

RESULTS: Bone integrity was restored in all the cases. Complete compensation of the defects was achieved in 12 patients with the first technique. Two patients with 8-cm ulna defects remained with residual discrepancy. In the forearm, mean compaction was 1.7 ± 0.4 cm. It took 25.7 ± 5.4 days followed by an average fixation period of 107.1 ± 11.8 days. In the tibia, mean longitudinal compaction by distraction measured 1.7 ± 0.8 cm. The second technique ended up with an acceptable shortening of 1 cm in two cases. Four centimeters were compressed in the third case gradually.

CONCLUSION: The technical solutions used for mechanical effects on the ischaemic distraction regenerate resulted in its rescue and bone union in all the cases.