Hexapod Circular Frame Fixation for Tibial Non-union: A Systematic Review of Clinical and Radiological Outcomes

INTRODUCTION: Tibial non-unions present with complex deformities, bone loss, infection, leg length discrepancy (LLD), and other features which influence function. Circular frame-based treatment is popular with the hexapod system used increasingly. This systematic review aims to determine the clinical and radiological outcomes of hexapod fixation when used for tibial non-unions. MATERIALS AND METHODS: The review was performed in accordance with preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. The search strategy was applied to MEDLINE and Embase databases on 15 December 2021. Studies reporting either clinical or radiological outcomes following hexapod fixation on tibial non-unions were included. Primary outcomes were radiological union and patient-reported outcome measures (PROMs). Secondary outcomes included LLD, tibial alignment deformity (TAD), return to pre-injury activity and post-operative complications. RESULTS: After the abstract and full-text screening, 9 studies were included; there were 283 hexapod frame fixations for tibial non-unions. Infection (46.6%) and stiff hypertrophic non-union (39.2%) accounted for most non-unions treated. The average age and mean follow-up were 42.2 years and 33.1 months, respectively. The average time to union was 8.7 months with a union rate of 84.8%. A total of 90.3% of patients had TAD below 5° in all planes, with an LLD ≤1.5 cm of the contralateral leg in 90.5%. Bony and functional results were at least good in over 90% of patients when using the Association for the Study of the Method of Ilizarov (ASAMI) criteria. A total of 84% of patients returned to pre-injury activities. There were complications as follows: a total of 34% developed pin-site infection, almost 9% experienced half-pin breakage and 14% developed an equinus ankle contracture. CONCLUSION: Hexapod frames for the treatment of tibial non-unions produce favourable functional outcomes. Complication rates are present and need to be discussed when this modality of treatment is proposed. Further comparative studies will allow for this option to be evaluated against that of the traditional Ilizarov frame and other methods of non-union surgery. HOW TO CITE THIS ARTICLE: Boksh K, Kanthasamy S, Divall P, et al. Hexapod Circular Frame Fixation for Tibial Non-union: A Systematic Review of Clinical and Radiological Outcomes. Strategies Trauma Limb Reconstr 2022;17(3):172–183.