Weight Bearing as Tolerated After Intramedullary Nailing of the Femur: A Retrospective Analysis of Clinical and...

Intramedullary nailing of femur fractures has become the standard of care, with high union rates. Few high-level studies have discussed the effect that early weight bearing has on the healing of these fractures, regardless of nail size or fracture pattern. The goal of this study was to determine the clinical and radiographic outcomes of femoral shaft fractures for patients allowed immediate weight bearing after intramedullary nailing. We performed a retrospective review of 341 femoral shaft fractures, with 131 allowed immediate weight bearing, 99 allowed partial weight bearing, and 111 kept non-weight bearing. Demographic, intraoperative, and postoperative variables were collected and analyzed. Increased fracture complexity was associated with higher likelihood of delayed weight bearing. No significant difference was found for nail size or rate of failure with different nail sizes. A total of 50 nonunions were noted (14.7%), with no difference in nonunion rates between weight bearing cohorts. The only significant predictor of nonunion was Orthopaedic Trauma Association (OTA) classification of OTA32B fractures (P=.02), which were 2 times and 4 times as likely to occur compared with OTA32A and OTA32C fractures, respectively. Failure of interlocking screws occurred among 15 patients (4.4%) and was more common with older patients, osteoporotic bone, and larger diameter nails. In summary, unilateral intramedullary nailing of adult femoral shaft fractures does not show a difference in fracture union rates or implant failure with unrestricted, immediate weight bearing, regardless of nail characteristics. [Orthopedics. 2022;45(3):e148-e153.].