Distal femur fractures stabilized using titanium lateral locked plates with nonlocking diaphyseal fixation: a retrospective review.

Objectives: Multiple treatment modalities exist for treating distal femur fractures. Lateral locked plating has become the method of choice because it prevents loss of reduction due to varus collapse, but has been associated with nonunion rates of up to 30%. Titanium implants may provide a more optimal biomechanical environment for fracture healing. The primary aim of this study is to evaluate nonunion rates and risk factors for nonunion in a series of distal femur fractures stabilized with modern locked titanium implants using all nonlocking diaphyseal fixation. A secondary aim is to evaluate whether diaphyseal fixation with nonlocking screws is associated with fixation complications.

Methods: A 6-year retrospective study identified patients undergoing operative fixation of distal femur fractures with lateral locked plating and nonlocking diaphyseal fixation. Patient demographics, fracture and fixation characteristics were recorded. Follow-up data recorded included fracture union, implant failure in the setting of nonunion and secondary procedures. Statistical analyses used include t test, Mann-Whitney U, and logistic regression.

Results: Eighty-one fractures met inclusion criteria with 16 fractures resulting in nonunion (19.75%). Comparing union and nonunion cohorts, nonunions were found to be associated with higher body mass index (P = 0.001). Fixation construct data found nonunions had a higher average number of diaphyseal screws (4.25 vs. 3.74, P = 0.038). Subgroup analysis found a nonunion rate of 4.2% (1 out of 24) in fractures with 3 diaphyseal screw fixation versus 26.3% (15 out of 57) with 4 or more diaphyseal screws (P = 0.038). No diaphyseal fixation failures were noted with nonlocking diaphyseal screw fixation.

Conclusion: Our study found using a titanium construct produced a nonunion rate of 19.75%, comparable with historic rates. Interestingly, diaphyseal fixation with more than 3 screws led to higher nonunion rates. No catastrophic failures were observed involving the diaphyseal nonlocking screw fixation.