Clinical outcomes of locked plating of distal femoral fractures in a retrospective cohort

Purpose: Locked plating (LP) of distal femoral fractures has become very popular. Despite technique suggestions from anecdotal and some early reports, knowledge about risk factors for failure, nonunion (NU), and revision is limited. The purpose of this study was to analyze the complications and clinical outcomes of LP treatment for distal femoral fractures. Materials and methods: From two trauma centers, 243 consecutive surgically treated distal femoral fractures (AO/OTA 33) were retrospectively identified. Of these, 111 fractures in 106 patients (53.8% female) underwent locked plate fixation. They had an average age of 54 years (range 18 to 95 years): 34.2% were obese, 18.9% were smokers, and 18.9% were diabetic. Open fractures were present in 40.5% with 79.5% Gustilo type III. Fixation constructs for plate length, working length, and screw concentration were delineated. Nonunion and/or infection, and implant failure were used as outcome complication variables. Outcome was based on surgical method and addressed according to Pritchett for reduction, range of motion, and pain. Results: Eighty-three (74.8%) of the fractures healed after the index procedure. Twenty (18.0%) of the patients developed a NU. Four of 20 (20%) resulted in a recalcitrant NU. Length of comminution did not correlate to NU (p = 0.180). Closed injuries had a higher tendency to heal after the index procedure than open injuries (p = 0.057). Closed and minimally open (Gustilo/Anderson types I and II) fractures healed at a significantly higher rate after the index procedure compared to type III open fractures (80.0% versus 61.3%, p = 0.041). Eleven fractures (9.9%) developed hardware failure. Fewer nonunions were found in the submuscular group (10.7%) compared to open reduction (32.0%) (p = 0.023). Fractures above total knee arthroplasties had a significantly greater rate of failed hardware (p = 0.040) and worse clinical outcome according to Pritchett (p = 0.040). Loss of fixation was related to pain (F = 3.19, p = 0.046) and a tendency to worse outcome (F = 2.43, p = 0.071). No relationship was found between nonunion and working length. Conclusion: Despite modern fixation techniques, distal femoral fractures often result in persistent disability and worse clinical outcomes. Soft tissue management seems to be important. Submuscular plate insertion reduced the nonunion rate. Preexisting total knee arthroplasty increased the risk of hardware failure. Further studies determining factors that improve outcome are warranted.