Body mass and weight thresholds for increased prosthetic joint infection rates after primary total joint arthroplasty

• Published in: Acta orthopaedica Vol. 87; no. 2; pp. 132 - 138
• Main Authors: Lübbeke, Anne, Zingg, Matthieu, Vu, Diemlan, Miozzari, Hermes H, Christofilopoulos, Panayiotis, Uçkay, Ilker, Harbarth, Stephan, Hoffmeyer, Pierre
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 03-03-2016; Medical Journals Sweden
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Anti-Bacterial Agents - therapeutic use; Antibiotic Prophylaxis; Arthroplasty, Replacement, Hip - adverse effects; Arthroplasty, Replacement, Knee - adverse effects; Body Mass Index; Body Weight - physiology; Cefuroxime - therapeutic use; Female; Follow-Up Studies; Hip; Humans; Incidence; Male; Middle Aged; Prospective Studies; Prosthesis-Related Infections - epidemiology; Prosthesis-Related Infections - etiology; Risk Factors; Treatment Outcome; Young Adult
• ISSN: 1745-3674; 1745-3682
• DOI: 10.3109/17453674.2015.1126157

Background and purpose - Obesity increases the risk of deep infection after total joint arthroplasty (TJA). Our objective was to determine whether there may be body mass index (BMI) and weight thresholds indicating a higher prosthetic joint infection rate.
Patients and methods - We included all 9,061 primary hip and knee arthroplasties (mean age 70 years, 61% women) performed between March 1996 and December 2013 where the patient had received intravenous cefuroxime (1.5 g) perioperatively. The main exposures of interest were BMI (5 categories: < 24.9, 25-29.9, 30-34.9, 35-39.9, and ≥ 40) and weight (5 categories: < 60, 60-79, 80-99, 100-119, and ≥ 120 kg). Numbers of TJAs according to BMI categories (lowest to highest) were as follows: 2,956, 3,350, 1,908, 633, and 214, respectively. The main outcome was prosthetic joint infection. The mean follow-up time was 6.5 years (0.5-18 years).
Results - 111 prosthetic joint infections were observed: 68 postoperative, 16 hematogenous, and 27 of undetermined cause. Incidence rates were similar in the first 3 BMI categories (< 35), but they were twice as high with BMI 35-39.9 (adjusted HR = 2.1, 95% CI: 1.1-4.3) and 4 times higher with BMI ≥ 40 (adjusted HR = 4.2, 95% CI: 1.8-9.7). Weight ≥ 100 kg was identified as threshold for a significant increase in infection from the early postoperative period onward (adjusted HR = 2.1, 95% CI: 1.3-3.6).
Interpretation - BMI ≥ 35 or weight ≥ 100 kg may serve as a cutoff for higher perioperative dosage of antibiotics.