Perioperative complications stratified by body mass index for the direct anterior approach to total hip arthroplasty.

Background: Previous studies have addressed the increased risk of perioperative complications in the obese and morbidly obese populations undergoing total hip arthroplasty. Over the last 15 years, the direct anterior approach has increased in popularity. The purpose of this study is to compare the 90-day perioperative complication rate of total hip arthroplasty performed through the direct anterior approach stratified by body mass index (BMI).

Methods: Perioperative complications both intraoperative and up to 90 days postoperative were identified in a case series of 1808 primary total hip arthroplasties performed through a direct anterior approach. The patients were stratified according to BMI. Demographics of age, side, sex, and American Society of Anesthesiologists score were recorded. Medical and surgical complications including National Surgical Quality Improvement Program complications, length of stay, reoperation rate, readmission rate, and length of operation were recorded. Bivariate analysis and analysis of variance were performed.

Results: Morbidly obese patients (BMI > 40) demonstrated increased American Society of Anesthesiologists scores, increased surgical times with statistically significant increase in number of patients with surgical complications, National Surgical Quality Improvement Program complications, deep infection, and wound breakdown. Grading the severity of complications also demonstrated the morbidly obese had a higher risk of experiencing more severe complications. Underweight patients (BMI < 18.5) demonstrated a statistically significant readmission rate.

Conclusion: In stratifying patients undergoing the direct anterior approach for total hip arthroplasty by BMI, a greater rate of surgical complications both in number and in severity occurs with the morbidly obese undergoing total hip arthroplasty through a direct anterior approach.