Intramedullary Fixation of Distal Fibula Fractures

Abstract

Category: Ankle; Trauma Introduction/Purpose: For unstable ankle fractures, surgeons typically employ the long-time standard of care; that is, open reduction and internal fixation with plate and screws. For patients with increased risk of soft tissue complications, a relatively newer construct includes intramedullary distal fibula fixation offering a viable option providing similar union rates, fracture alignment, and theoretical lower infection rate. Our study examines an intramedullary system with a novel design featuring fixation by proximal talons ensuring maintenance of alignment, rotation, and prevention of fracture settling. Our research builds on recent published work evaluating this intramedullary device. However, our study is the largest case-series, to our knowledge to assess time to weightbearing, fracture union and union rate as well as the first to assess safety and reproducibility of percutaneous reduction. Methods: A retrospective case-series was conducted on all skeletally mature patients with unstable ankle fractures treated with the same intramedullary distal fibular fixation. Surgeries were performed by a single surgeon between September 2015 and August 2019. Patient post-operative imaging was carefully assessed for quality of reduction, classifying reductions as ‘good,’ ‘acceptable,’ or ‘poor,’ also assessing for union and fracture settling. Patient charts were also assessed for comorbidities, injury pattern, fracture classification, associated injuries, fracture reduction method, perioperative complications, tourniquet time, characteristics of fracture union, time to weight bearing, and need for additional surgery. Results: Fifty-one patients were included in the study. Mean follow-up time was 32.2 weeks. Four fractures were bimalleolar (7.8%), 44 were isolated distal fibula fractures (86.3%), and 3 were trimalleolar fractures (5.9%). Two percent were Weber A, 77% Weber B, and 11% Weber C. Thirty-five (69%) reductions were achieved closed or percutaneously without complications. Based on reduction classification system, 47 fracture reductions (92%) were classified as ‘good’ and 4 (8%) were ‘acceptable’. All but one fracture (98%) went on to union. Average time to union was 10.3 weeks. Average weightbearing in a walking boot was at 6.8 weeks and 11.2 weeks without immobilization. One patient (2%) had a superficial wound infection, and there were no deep infections. Diabetes, smoking, and neuropathy were not predictive of complications. Conclusion: Our study strengthens the growing body of evidence supporting the safety and efficacy for a novel intramedullary device with unique proximal fixation. To our knowledge, this is currently the largest retrospective case-series in the literature evaluating this device. Fracture union and union rates were found to be acceptable for unstable ankle fracture patterns and infections rates were found to be very low, consistent with previous research. Percutaneous reduction of the lateral malleolus did not result in any injury to nearby anatomic structures or unsatisfactory fracture alignment. Lastly, consistent time to weight bearing following surgery could safely be achieved without consequence.