Surgical Site Fat Thickness Is More Predictive of Postoperative Wound Complications than Body Mass Index Following Posterior Approach Total Hip Arthroplasty

摘要

BACKGROUND: Body mass index (BMI) is widely utilized to counsel patients on complication risk following total hip arthroplasty (THA). However, BMI is unable to account for fat distribution. The existing literature is sparse regarding the effect of surgical site fat thickness (SSFT) on perioperative risk in THA. The purpose of the study was to compare BMI and SSFT with acute postoperative complications following THA. METHODS: A retrospective review of 167 consecutive, posterior approach, robotic-arm-assisted THAs between May 2022 and May 2024 at a tertiary academic institution was performed. Computed tomography scans were available for all cases. On the axial computed tomography, SSFT from the iliotibial band to skin at the level of the vastus ridge was measured in mm. A chart review was performed for perioperative variables and acute (within 90 days postoperatively) surgical complications, reoperations, and revisions. T-tests, bivariate regression, and receiver operating characteristic curve analyses were performed. RESULTS: Mean BMI was 33.1 (range, 18.9 to 44.3), and mean SSFT was 52.4 mm (range, eight to 99). Within 90 days, there were 15 (9%) complications, all of which were wound- or infection-related; seven (4.2%) were managed with reoperation. Of these, four (2.4%) underwent debridement, antibiotics, and implant retention (DAIR), and three (1.8%) had superficial incision and drainage. With univariate analysis, SSFT was associated with complications (P < 0.01), reoperations (P < 0.01), and DAIR (P = 0.03). Body mass index (BMI) was associated with complications (P = 0.02), but was not associated with reoperations (P = 0.05) or DAIR (P = 0.27). With bivariate regression, SSFT was predictive of complications (P = 0.03, odds ratio 1.04) and reoperations (P = 0.04, odds ratio 1.05), while BMI was not (P > 0.05 for both). Threshold values for complications and reoperations were SSFT of 51.5 mm area under the curve, 0.73) and 64.5 mm (area under the curve, 0.81), respectively. CONCLUSIONS: Compared to BMI, SSFT was more predictive of postoperative wound complications following THA and may be a more reliable measure to counsel patients on early postoperative complication risk.