Bone Transport to Arthrodesis for Ankle and Hindfoot Osseous Defects

CATEGORY: Trauma; Ankle; Hindfoot INTRODUCTION/PURPOSE: Distal tibia and hindfoot bone defects represent a challenging scenario for the foot and ankle surgeon. Recovering bone stock whilst achieving fusion in an infection-free environment with no soft tissue defects are the main objectives to obtain limb salvage. Bone transport to arthrodesis using distraction osteogenesis is a two-staged procedure for the management of intercalary defects. The initial stage consists of resection of non-vital osseous tissue and installation of a cement spacer. The second stage is performed after the infection process and soft tissue cover is completed and consists of a proximal tibial corticotomy with the installation of a circular external fixation. There are few reports in the literature of the salvage rate, functional/quality of life outcomes and satisfaction results of this technique. METHODS: Retrospective IRB-approved study including patients with distal tibial and hindfoot bone defect treated in a trauma level I center between January 2015 and February 2020. We included patients treated with bone transport to tibiotalar o tibiocalcaneal arthrodesis using a circular external fixator with a minimum 12 months follow-up after frame removal. Demographic and clinical data were obtained. In addition, union rates, external fixator times and complications were noted. SMFA and SF-12 scores were obtained for assessing functional results and quality of life respectively. Residual pain was evaluated using a visual analog scale and patient's satisfaction was assessed with a likert-type categorical scale. RESULTS: Eighteen patients with a mean age of 50.9 years (R:24-72) were included in this study. The mean defect size was 7.3 cm (R:3-12) with osteomyielitis of the distal tibia secondary to trauma as the most common etiology. Fifteen cases were transported to tibiotalar artrhodesis and in three cases to tibiocalcaneal artrhodesis. Free flaps were used to cover soft tissue defects in 10 patients (56%). Union rate was 94% (17/18 patients) with one patient requiring a below knee amputation for persistant infection during bone transport. The mean fixator time was 12 months (R:5-20). Conversion to internal fixation was performed in 12 patients. The mean SMFA dysfunction score was 37.9 and bother score 45.3. SF-12 results were 30.5 in the physical score and 45.5 regarding mental health. The mean VAS was 4 and sixteen patients were completely satisfied or satisfied with minor remarks with the procedure (89%). CONCLUSION: Bone transport to arthrodesis obtained a high rate of limb salvage in this series as a treatment for segmental osseous deficits of the hindfoot and ankle. Nevertheless is a technique that requires a long recovery and external fixation time. Patients at one-year follow-up after frame removal have lower functionality and quality of life scores than the general population but with a high rate of satisfaction.