Functional Outcome of Distraction Osteogenesis Using Linear Rail System (LRS) in Adults with Isolated Femoral Bone Gap

Background: The management of bone gap in the femoral shaft has remained difficult and challenging to the orthopaedic and trauma Surgeons. Distraction osteogenesis using the linear rail system (LRS) may be a useful tool in bridging such defects in our environment. Objective: To study the radiologic bone union, functional outcome and complications of distraction osteogenesis in the management of femoral bone gap using linear rail system (LRS). Methodology: A hospital based prospective interventional study conducted at National Orthopaedic Hospital, Dala and Albarka clinic, Dandishe, Kano, between March 2013 and March 2018. Sixty-eight cases were recruited. Every patient had LRS applied after adequate debridement when needed. Primary or interval corticotomy was done depending on the extent of soft tissue dissection in relation to the corticotomy site. Follow up was done until the regenerate had corticalized and LRS removed. Complications were noted and recorded. Radiologic union and functional outcome were assessed using the RUST and ASAMI outcome scores respectively. Data was analyzed using SPSS version 20. Results: Sixty-eight cases were recruited with M: F ratio of 16: 1. The mean age was 36.7 +/- 10.5years. The age range between 36-45years was more commonly treated representing 34(50.0%). Primary corticotomy was done in 52 (76.5%) while interval corticotomy was done in 16 (23.5%). The mean regenerate length achieved was 9.6 +/- 2.7cm. The mean duration of treatment was 20.3 +/- 6 months. Radiologic union was achieved in 66 (97.1%) patients. Sixty-four (94.1%) had excellent or good ASAMI functional outcome scores. Sixty-six (97.1%) were either very satisfied or satisfied with their treatment while 2 (2.9%) were indifferent. The common complications were intermittent pin tract infections recorded in 28 (41.2%), knee stiffness in 18 (26.5), proximal or distal varus deformity in 10 (14.7%) and non-union in 2 (2.9%) of cases. Conclusion: Distraction osteogenesis using LRS can achieve bone union and excellent outcome in the management of bone gap in the femur. However, intermittent pin tract infection, knee stiffness and varus deformities post significant challenges.