Increased Complications in Obese Patients Undergoing Direct Anterior Total Hip Arthroplasty

The direct anterior (DA) approach for total hip arthroplasty (THA) has demonstrated successful short term outcomes in several studies. However, there is no consensus about which patients are appropriate candidates for DA total hip arthroplasty. It is also unclear if short term outcomes in obese patients undergoing THA through a DA approach are elevated in comparison to non-obese patients. The purpose of this study was to evaluate complication rates and short term outcomes of obese, pre-obese, and normal body mass index (BMI) patients undergoing THA with a DA approach in a consecutive group of patients. This study was a retrospective review of 210 consecutive patients who underwent unilateral THA through a DA approach for osteoarthritis or avascular necrosis during the early peri-operative period. The study included 61 patients with normal BMI, 70 pre-obese patients, and 79 obese patients according to World Health Organization (WHO) classification (49 class I obese, 22 class II obese, and 8 class III obese patients). Patient charts were reviewed to determine differences in surgical time, length of stay, disposition, major complications, wound complications, and short term outcome measures. When comparing normal and pre-obese patients (BMI <30) to a combined group of WHO class I, II, and III obese patients (BMI >30), the obese group demonstrated increased surgical times by 12.7 minutes (P<0.0001), as well as increased length of stay (P=0.0303), narcotic use (P=0.0037), and assistive device use at two weeks (P<0.0030). In addition, major complications and wound complications were both significantly increased in the obese group (odds ratio [OR], 8.8; P=0.0493 and OR, 3.6; P=0.0431, respectively). There was also a trend toward increased use of rehabilitation facilities in the obese group at disposition, 15.4% vs 7.6% (P=0.0774). This study demonstrates that obese patients undergoing a DA approach have a 8.8 and 3.6 times increase in major and wound complications, respectively, compared to patients with a BMI <30. Obese patients also demonstrated significant increases in operative time, use of narcotics, use of assistive devices, and length of stay. There was a trend toward higher use of rehabilitation placement. While significant, these findings are similar to complication rates in the literature for other THA operative approaches. This study further defines the risks associated with performing THA on obese patients regardless of approach.