Early versus delayed weight bearing after surgical fixation of distal femur fractures: a non-randomized comparative study

Distal femur fractures are rare injuries with a bimodal distribution (high-energy injury in young males and low-energy fragility fractures in old females). Their management can be challenging: open reduction and internal fixation (ORIF) with distal femur locking plates is a commonly performed procedure especially in comminuted fractures with articular involvement. Anxiety regarding the stability of the fixation, especially in osteoporotic bone, leads to post-operative restrictive instructions with limitations regarding the weight-bearing status. Early weight bearing (EWB), however, was shown to enhance bone healing and was not correlated with an increased risk of fracture displacement or implant failure in previous published studies, which reported the results of proximal femur, tibia and ankle fractures surgical treatment. The current study analysed the results of a series of distal femur fractures (51 patients, mean age 64.3 ± 20.7) all treated with ORIF in a level-I major trauma centre, but differently rehabilitated. Group A was, in fact, instructed not to weight bear or to touch weight bear, while group B started to weight bear soon after surgery without specific restrictions. The objective was to compare the outcome and the complication rate in the two groups at 6 and 12 weeks after surgery. The results showed no statistically significant differences in the two groups and no post-operative complications in the EWB group. Six complications were observed in the non-weight-bearing group (four fractures displacement and two implants failure at 12-week follow-up). Distal femur fractures treated with locking plates can be rehabilitated with EWB to allow early return to function. There is no evidence that EWB increases the risk of fracture displacement or implant failure in distal femur fractures treated with distal locking plates. Instead, it is possible that post-operative non-weight-bearing status delays the fracture-healing process increasing the risk of failure of the fixation.