Subtrochanteric Femur Fractures: The Association Between Obesity and Perioperative, Clinical, and Radiographic Outcomes

Abstract

To evaluate the association between obesity and treatment approaches, perioperative factors, and clinical and radiographic outcomes following subtrochanteric fracture fixation. METHODS: Design: Retrospective Cohort Academic Medical Center Patients operatively treated for an AO/OTA 32Axa, 32Bxa, or 32Cxa subtrochanteric femur fracture. Outcome Measures and Comparisons: Injury characteristics, perioperative parameters, fixation information, postoperative complications, clinical and radiographic outcomes. Univariable analyses were conducted between the obese (BMI > 30 kg/m2) and the non-obese (BMI < 30 kg/m2) cohorts. Regression analyses were performed to assess BMI as a continuous variable Of 230 operatively treated subtrochanteric fracture patients identified, 49 (21%) were obese and 181 (79%) were non-obese. The average age of the obese cohort was 69.6 ± 17.2 years, with 16 (33%) males and 33 (77%) females. The average age of the non-obese cohort was 71.8 ± 19.2 years, with 60 (33%) males and 121 (77%) females. Aside from BMI, there were no significant differences in demographics between the obese and non-obese (age [p=0.465], gender [p=0.948], ASA Score [p=0.739]). Both cohorts demonstrated similar injury characteristics including mechanism of injury, atypical fracture type, and AO/OTA fracture pattern (32A, 32B, 32C). Obese patients underwent more open reduction procedures (59% open obese, 11% open non-obese, p<0.001), a finding further quantified by a 24% increased likelihood of open reduction for every 1 unit increase in BMI (OR: 1.2, 95% CI: 1.2-1.3, p<0.001). There was no difference in average nail diameter, 1 vs 2-screw nail design, or number of locking screws placed. The obese cohort was operated on more frequently on a fracture table (p<0.001) when compared to the non-obese cohort which was operated on more frequently on a flat table (p<0.001). There were no significant differences (p>0.050) in postoperative complications, mortality/readmission rates, hospital quality measures, fixation failure or time to bone healing. The treatment of subtrochanteric fractures in obese patients is associated with a higher likelihood of surgeons opting for open fracture reduction and the use of different operating room table types, but no difference was observed in postoperative complications, mortality or readmission rates, or healing timeline when compared to non-obese patients. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.