Early Weight Bearing on Supracondylar Distal Femur Fractures in Elderly Patients

Supracondylar femur fractures represent 4-7% of femur fractures. These are a common orthopaedic injury with an overall incidence of 37 per 100,000 person-years. These fractures are complex and challenging for orthopaedic surgeons. The fracture needs to be correctly reduced and, like nearly all fractures, fixed with enough stability to permit early joint motion. This allows for earlier patient rehabilitation, which can improve outcomes. There are a number of different fixation devices. Fixed angle implants such as retrograde intramedullary nails, angled blade plates, and 95-degree side plates have had good clinical outcomes with resistance to varus collapse. Recently, locking plates have become the standard method for distal femoral fracture fixation. Hendersen et al. provided a systematic review of locking plate fixation and demonstrated the range of complications as 0% to 32% and implant failure occurring late with 75% of failures occurring after 3 months and 50% occurring after 6 months. Ricci et al. sought to determine risk factors associated with failure of locked plate fixation of distal femur fractures and found that 19% required reoperation. The risk factors for reoperation found in this study were diabetes, smoking, increased body mass index, shorter plate length and open fracture. Most factors are out of surgeon control but are important to evaluate when considering prognosis.

After the fracture has been open reduced and internally fixed, there is debate on postoperative management of weight bearing. Weight bearing following fixation is generally restricted for 6 to 12 weeks until radiologic evidence of evidence demonstrates sufficient callous. This restricted weight bearing is primarily due to concerns of implant failure and loss of reduction. A study by Brumback et al. examined intramedullary nail fixation of distal femur fractures and concluded to allow full weight bearing of comminuted femoral shaft fractures with antegrade intramedullary nail. This study led surgeons to accelerate their rehabilitation protocols.

The post-operative weight bearing recommendations for distal femur fractures treated with locking plate vary widely which motivated Granata et al. to evaluate the biomechanics of immediate weight bearing of distal femur fractures treated with locked plate fixation. They found that the fatigue limit of the locked plate constructs was 1.9 times body weight for an average 70-kilogram patient over a simulated 10-week postoperative course. Although this study could not fully support immediate weight bearing due to the fact that femoral loads during gait have been estimated to be around 2 times body weight, it demonstrated adequate hardware fixation with weight bearing.

The benefits of early weight bearing are accelerated functional recovery, increased independence, decreased impact on the family, increased psychological benefits, reduced use of healthcare resources, decreased need for family intervention, and family to take care of the patient. The downside is the strength of fixation, the risk of implant failure, and the risk of loss of reduction. The goals are to evaluate the fracture, the complication rate, the mortality rate, and the risks of healthcare resources that have been used.