Accuracy, Efficacy and Limits of Hexapod External Fixators in the Treatment of Lower Limb Complex Deformity

Aim:The aim of the present study was to assess the precision, safety and limits of hexapod external fixator (HEF) systems for the correction of primary and secondary lower limb deformities and for the treatment of lower limb complex fractures [damage control setting -damage control orthopaedics (DCO)] in a consecutive series of 16 patients.Materials and methods: Clinical and radiographic data of 16 consecutive patients with primary and secondary complex lower limb deformities or lower limb complex fractures (DCO) were analysed.The difference between pre-operative and post-operative deformity measurements on X-rays was compared in order to assess the efficacy of the hexapod systems used.The precision of the hexapod systems in deformity correction was expressed as the agreement between pre-operative planning values and final correction values.Results: A statistically significant difference between pre-operative and post-operative deformity parameters (p = 0.01) for both angular and linear parameters was found confirming the deformity correction to be effective.The difference between planned values of correction and obtained values of correction was statistically significant for angular corrections (p = 0.010) but not for linear corrections (p = 0.12). Conclusion:The HEF is an efficient treatment of both acute traumatic and primary or secondary chronic complex deformities of the lower limbs.The difference found between software-generated correction planning and end-correction parameters for angular corrections reveals a limit of the hexapod system.