33 Impact of Disruption of Tibio-Fibular Joints During Distraction Osteogenesis on Knee and Ankle Joint Function

Abstract

Abstract Aim The aim of this study is to investigate whether a disruption of proximal and/or distal tibio-fibular joint correlates to patient’s function and osteoarthritis. Method Retrospective analysis of 44 patients with lower limb bone defects treated by tibial corticotomy and distraction osteogenesis was conducted. Analysis of lower limb x-rays before surgery, immediately post-surgery and after frame removal permitted calculations of changes in tibial length and changes in fibula position relative to the tibia at the proximal and distal tibio-fibular joints. X-rays before and after treatment were also graded for osteoarthritis severity using Alhbäck's classification. Functional ability was scored using the American Orthopaedic Foot & Ankle Society (AOFAS) score and the Knee society score (KSS). Results 15 patients showed a decrease in the distance between fibular tip and distal tibia, 5 showed no change and 12 showed an increase at the end of the treatment. No statistical significant association was noted with KSS or AOFAS score (p > 0.05), however one patient with a large distance increase exhibited severe radiological exacerbation of knee osteoarthritis. The distal corticotomy group achieved significantly higher length of new bone (p < 0.001) and were more likely to have exacerbation of knee osteoarthritis (p < 0.05). Conversely, proximal corticotomy group were significantly more likely to show an exacerbation of ankle osteoarthritis (p < 0.05). Conclusions Attempts should be made not to disrupt the tibio-fibular joints during bone transport, but disruption does not necessarily correlate to poorer outcomes. Our results show that lengthening index reduces with larger bone defects, suggesting that radical debridement/resection may not negatively affect the healing index.