Risk factors for failure of locked plate fixation of distal femur fractures: an analysis of 335 cases.

OBJECTIVES: Locked plating has become a standard method to treat supracondylar femur fractures. Emerging evidence indicates that this method of treatment is associated with modest failure rates. The goals of this study were to determine risk factors for complications and to provide technical recommendations for locked plating of supracondylar femur fractures. DESIGN: Retrospective review. SETTING: Three level I or II trauma centers. PATIENTS/PARTICIPANTS: Three hundred twenty-six patients with 335 distal femur fractures (OTA 33A or C, 33% open) treated with lateral locked plates were studied. The average patient age was 57 years (range 17-97 years), 55% were women, 34% were obese, 19% were diabetic, and 24% were smokers. INTERVENTION: All patients were managed with open reduction internal fixation using a lateral distal femoral locked plate construct that included locked screws in the distal fragment and nonlocked, locked, or a combination of locked and nonlocked screws in the proximal fragment. MAIN OUTCOME MEASUREMENTS: Risk factors for reoperation to promote union, deep infection, and implant failure. RESULTS: After the index procedure, 64 fractures (19%) required reoperation to promote union, including 30 that had a planned staged bone grafting because of the metaphyseal defect after debridement of an open fracture. Independent risk factors for reoperation to promote union and deep infection included diabetes and open fracture. Risk factors for proximal implant failure included open fracture, smoking, increased body mass index, and shorter plate length. CONCLUSIONS: The identified risk factors for reoperation to promote union and complications included open fracture, diabetes, smoking, increased body mass index, and shorter plate length. Most factors are out of surgeon control but are useful when considering prognosis. Use of relatively long plates is a technical factor that can reduce risk for fixation failure. LEVEL OF EVIDENCE: Prognostic level II. See instructions for authors for a complete description of levels of evidence.