Management of bone defects at tibial metaphysis by bone transport technique with linear-circular hybrid external fixators

Abstract

Objective To report our successful clinical experience of managing tibial metaphyseal bone defects with linear-circular hybrid external fixators to restore limb functions.Methods We managed and fully followed 9 male patients with tibial metaphyseal bone defects from December of 2009 to February of 2013.They were aged from 25 to 66 years (average,45.0 years).Four had a proximal end and 5 a distal end affected;5 cases were infected and 4 non-infected.The average length of tibial shortening was 13.0 mm (from-2 to 30 mm) before operation;the mean length of bone defects was 8.3 cm (from 4 to 13 cm).The non-infected patients were managed with debridement and trimming at the defect end,and primary fixation with linear-circular hybrid external fixators,followed by immediate or delayed osteotomy and bone lengthening after one or two months at the normal metaphyseal end.The infected patients were managed with debridement and fixation before the defects were filled with antibiotics-impregnated bone cement or artificial bone.The osteotomy and bone lengthening was performed secondarily.The fixators were not removed until consolidation was noticed in both the distracted area and the docking site and the patients were able to ambulate without aids.Results On average the 9 were followed up for 22.4 months (from 16 to 35 months).They achieved bony healing in both the distracted area and the docking site.Their average distraction length was 8.9 cm (from 5 to 13 cm).The leg length discrepancy was 4 mm (from1 to 14 mm)shorter on average after operation except in one patient with shortening and equinus deformity who refused correction.The average external fixation index (EFI) was 1.8 month/cm (from 1.2 to 2.6 month/cm).No infection relapsed.According to Paley's criteria,the bony results were excellent in 7 and good in 2 cases,and the functional results were excellent in 4 and good in 5 cases.The total complication rate was 1.4 per patient.Conclusions Bone transport technique with linear-circular hybrid external fixators is effective in management of tibia1 non-union with metaphyseal bone defects because it can preserve functions of the adjacent joints and stabilize securely the small peri-articular segments of cancellous bone.However,surgeons should be prudent in stimulating bone union at the docking site by gradual compression through linear-circular hybrid external fixators.Autograft is strongly recommended at the docking site. Key words: Tibia; Ilizarov technique; Bone lengthening