Dynamic fixation of distal femur fractures using far cortical locking screws: a prospective observational study.

OBJECTIVES: Document fixation and healing of distal femur fractures stabilized by plate osteosynthesis using far cortical locking (FCL) screws.

DESIGN: Prospective and observational.

SETTING: Two level 1 and 1 level 2 trauma centers.

PATIENTS: Thirty-two consecutive patients with 33 distal femur fractures (AO/OTA types 33A, 33C).

INTERVENTION: Fractures were stabilized by plate osteosynthesis with MotionLoc FCL screws without supplemental bone graft or bone morphogenic proteins. Patients were followed up for a minimum of 1 year with functional and radiographic assessments obtained at postoperative weeks 6, 12, and 24 and computed tomography scans at week 12. If union was not confirmed within 1 year, follow-up was continued until union or revision surgery.

MAIN OUTCOME MEASURES: The primary end point was fracture union in the absence of complications and secondary interventions. Fracture healing was defined by resolution of pain at the fracture site and cortical bridging on biplanar radiographs. Complications were defined by fixation failure, loss of reduction, implant breakage, infection, nonunion, and need for revision.

RESULTS: Thirty-one fractures were available for follow-up. None of the 125 FCL screws used for diaphyseal fixation broke or lost fixation. One of the 31 fractures displaced into varus (ΔVarus = 5.8 degrees). Thirty of the 31 fractures healed within 15.6 ± 6.2 weeks. At an average follow-up of 17 ± 4 months, there were 2 revisions: one to correct a malrotation at day 5 and one to treat a nonunion at 6 months.

CONCLUSIONS: Absence of implant and fixation failure suggests that dynamic plating of distal femur fractures with FCL screws provides safe and effective fixation.