Evaluation of BMI and fat distribution as potential risk factors for infection and wound healing complications in total hip arthroplasty

Obesity has been associated with surgical post-operative complications after joint replacement, such as surgical site infection (SSI) and other wound healing complications (WHCs), which are feared complications associated with worsened outcomes for both the patient and the healthcare. However, there are conflicting reports regarding utilization of body mass index (BMI) as a measure of risk, as it does not consider body-composition nor the distribution of fat relative to the surgical site. This study evaluated the relationship between site-specific fat distribution and wound healing complications following total hip arthroplasty (THA). Incidence rates were calculated for surgical site fat depth (SSFD), BMI, SSI, and WHCs according to the total number of surgeries. SSFD was measured intraoperatively for 97 consecutive THA procedures in 88 patients. Retrospective chart reviews were conducted on the cohort with minimum of 3-month follow-up to assess incidence of SSI/WHC and possible association with SSFD with subgroup analysis performed to identify other patient-specific risk factors. Eight patients (9%) experienced WHCs, in which two patients (2%) experienced SSI. Fat depths at the hip joint were associated with obesity and increased in a BMI-dependent manner. High BMI values and fat depths ≥3 cm were associated with greater risk for post-operative WHCs, with obesity Type 2 and 3 demonstrating a higher observed risk for SSI. BMI and SSFD may both be predictors in evaluating the probability of a WHC/ SSI risk and warrant further prospective evaluation.