Injury patterns and outcomes associated with fractures of the native distal femur in adults

Purpose: Previous studies on distal femur fractures had a high degree of inclusion criteria in their sample populations, some even including pre-existing implants. The authors look to define an injury pattern unique to fractures of the distal femur by detailing demographics, associated injuries, and outcomes.

Methods: This retrospective chart review identified 171 patients who presented to our Level 1 academic trauma center with a distal femur fracture, of which 91 injuries met inclusion for final analysis. For each patient, demographics, fracture classification, associated injuries, hospital outcomes, union rate, and complication rate were recorded. These characteristics were compared in high-energy injury versus low-energy injuries.

Results: Additional orthopedic injuries, most commonly an ipsilateral patella or tibia fracture (p = 0.02), were more likely to occur in patients who sustained high-energy injuries (86%, p = 0.0001). High-energy injuries resulted in more severe distal femur fracture types and significantly greater rate of open fractures (19.8% of all fractures, p = 0.0001). High-energy injuries were also associated with long operating room times during fixation (p < 0.001), estimated blood loss during surgery (p = 0.03), and hospital length of stay (p = 0.04). Finally, high-energy injuries were also associated with lower union rates (p = 0.036) and a higher rate of additional surgeries (p = 0.011).

Conclusion: Patients who sustain a distal femur fracture have a greater risk for additional fractures (particularly ipsilateral tibia and patella fractures), open injuries, and non-orthopedic traumatic injuries. These high-energy injuries are also associated with a more complicated clinical course and lower rate of union compared to low-energy injuries.

Level of evidence: Prognostic level III.