External fixation followed by cast immobilization in the management of gustilo-anderson iiia and iiib open tibial fractures

Background: The ideal method for definitive management of open tibia fractures has been a subject of debate. Several techniques have been tried with mixed results. Objectives: To describe and present our experience using external fixator interrupted by cast immobilization in the management of Gustillo-Anderson IIIA and IIIB open tibia fractures guided by the radiographic union scale of tibia fractures. Methods: Patients with Gustillo-Anderson IIIA and IIIB tibia fractures admitted into Nnamdi Azikiwe University Teaching Hospital had debridement and stabilization with external fixators. Subsequently, fracture healing was monitored with radiographs while wounds were cared for with dressings. At Radiographic Union Scale for Tibial Fractures (RUST) score of 4, external fixators were taken down and above knee plaster of Paris cast applied. Partial weight bearing was commenced at RUST 6 (cast still in place). Cast was removed at RUST 11 and full weight bearing commenced at RUST 12. Outcome of this method was assessed. Results: Gustillo-Anderson IIIA accounted for 43.1% while IIIB accounted for 56.9%. Mean presentationintervention interval was 41.5 hours ±3.3. Mean time to partial weight bearing was 14.2 weeks ±1.8 (GA IIIA) and 15.6 weeks ±2.6 (GA IIIB). Mean duration on cast was 12.4 weeks (GA IIIA) and 17.5 weeks (GA IIIB). Union occurred at a mean time of 29.9 weeks (GA IIIA) and 35.6 weeks (GA IIIB). Polymicrobes were seen in both classes. Non union rate was 17.6%. Conclusions: Management of open tibia fractures with external fixator and conversion to cast immobilization results in good healing. Presentation-intervention interval of close to 48 hours does not significantly affect pin tract infection rates. RUST is a useful guide for safe graduation of patients with tibia fractures across the stages of treatment rehabilitation.