The Management of Tibial Bone Defects: A Multicenter Experience of Hexapod and Ilizarov Frames.

INTRODUCTION: Bone defects may be managed with bone transport or acute shortening and lengthening using circular external fixation devices. We performed a multicenter retrospective cohort study to compare the outcomes between the Ilizarov frames and hexapod frames for the management of bone defects. METHODS: Patients treated for bone defects using either Ilizarov or hexapod frames were included for analysis in two specialist institutions. Primary outcomes were time to consolidation, bone healing index (BHI), and external fixator index (EFI). Radiographic parameters included the medial proximal tibial angle, lateral distal tibial angle, posterior proximal tibial angle, and anterior distal tibial angle. RESULTS: There were 137 hexapods and 90 Ilizarov frames in total. The mean time to follow-up was 3.7 years in the hexapod group and 4.0 years in the Ilizarov group. Hexapods had a significantly lower time to consolidation (253 days versus 449 days) (P < 0.0001) and BHI (59.1 days/cm versus 87.5 days/cm) (P < 0.0001). Hexapods had a significantly better EFI (72.3 days/cm versus 96.1 days/cm) (P = 0.0009). CONCLUSION: Hexapods may confer a significant advantage over Ilizarov frames in the management of bone defects. Time to consolidation, radiographic parameters, BHI, and EFI are all superior in hexapods.

Biomechanical Analysis of the Behaviour at the Metaphyseal-Diaphyseal Junction of Complex Tibial Plateau Fractures Using Two Circular Fixator Configurations.

BACKGROUND: High-energy tibial plateau fractures are challenges in treatment with controversy over operative stabilisation, especially for fractures with metaphyseal-diaphyseal dissociation. Treatment with percutaneous or minimally invasive direct reduction techniques, usually associated with circular external fixation, has generated interest although there is no consensus regarding the type of external fixation to be used. AIM: This study aims to compare the two hybrid circular external fixation mountings used to treat the high-energy tibial plateau fractures. METHODS: Two different groups of hybrid circular external fixation frame mountings were assembled using composite tibiae with proximal metaphyseal osteotomies simulating tibial plateau fractures with metaphyseal-diaphyseal dissociation. The standard all-wire frame mounting was assembled, and the comparison frame mounting had the distal K-wires replaced with half-pins. Both groups were tested through cyclic loading between 300 and 1000 N for 10,000 cycles. Interfragmentary linear and rotational displacements were analysed. RESULTS: The standard frame mounting behaved similarly to a classic Ilizarov frame, allowing greater axial movement (mean, 3.76 ± 0.26 mm in the standard group and 3.02 ± 0.23 mm in the test group) and smaller mediolateral displacement compared with the test frame (mean, 0.17 ± 0.16 mm compared to 0.56 ± 0.12 mm). The test frame behaved more similarly to a linear external fixator and provided greater axial stability, similar anteroposterior displacement, and lower mediolateral stability. Despite these differences, in both groups the axial displacement was greater than the prejudicial nonaxial movements. CONCLUSION: Increasing the number of half-pins and decreasing the number of K-wires in hybrid circular external fixation generate frames that tend to behave more similarly to the linear external fixators. HOW TO CITE THIS ARTICLE: Cardoso GS, Amorim R, Penha FM, et al. Biomechanical Analysis of the Behaviour at the Metaphyseal-Diaphyseal Junction of Complex Tibial Plateau Fractures Using Two Circular Fixator Configurations. Strategies Trauma Limb Reconstr 2020;15(3):138-145.