Incidence, Risk Factors, and Subsequent Complications of Postoperative Hematomas Requiring Reoperation After Primary Total Hip Arthroplasty

BACKGROUND: Studies analyzing the incidence and clinical implications of postoperative hematomas after total hip arthroplasty (THA) remain limited. The purpose of the present study was to use the National Surgical Quality Improvement Program (NSQIP) dataset to determine rates, risk factors, and subsequent complications of postoperative hematomas requiring reoperation after primary THA. METHODS: Study population included patients who underwent primary THA (CPT code: 27130) from 2012-2016 recorded in NSQIP. Patients who developed a hematoma requiring reoperation in the 30-day postoperative period were identified. Multivariate regressions were created to identify patient characteristics, operative variables, and subsequent complications that were associated with a postoperative hematoma requiring reoperation. RESULTS: Among the 149,026 patients who underwent primary THA, 180 (0.12%) developed a postoperative hematoma requiring reoperation. Risk factors included body mass index (BMI) ≥ 35 (relative risk [RR]: 1.83, P = .011), American Society of Anesthesiologists (ASA) class ≥3 (RR: 2.11, P < .001), and history of bleeding disorder (RR: 2.71, P < .001). Associated intraoperative characteristics were an operative time ≥100 minutes (RR: 2.03, P < .001) and use of general anesthesia (RR: 1.41, P = .028). Patients developing a hematoma requiring reoperation were at higher risk of subsequent deep wound infection (RR: 21.57, P < .001), sepsis (RR: 4.3, P = .012), and pneumonia (RR: 3.69, P = .023). CONCLUSIONS: Surgical evacuation for a postoperative hematoma was performed in about 1 in 833 cases of primary THA. Several nonmodifiable and modifiable risk factors were identified. Given the 21.6 times increased risk of subsequent deep wound infection, select, at-risk patients may benefit from closer monitoring for signs of infection.