Relationship between body mass index and the risk of periprosthetic joint infection after primary total hip arthroplasty and total knee arthroplasty

Background: Periprosthetic joint infection (PJI) is a disastrous complication after total hip arthroplasty (THA) and total knee arthroplasty (TKA). The relationship between body mass index (BMI) and the incidence of PJI remains controversial. To better understand the impact of increasing BMI on PJI, we conducted this study to investigate the dose-response relationship between BMI and the risk of PJI after primary THA or TKA. Methods: A systematic search was conducted in PubMed, Embase, and Cochrane Library databases from inception to August 17, 2019. After study selection and data extraction, a dose-response meta-analysis was performed to investigate the relationship between BMI and PJI. Adjusted relative risks (RRs) with 95% confidence intervals (CIs) were pooled using fixed-effects or random-effects models. Results: Eleven studies comprising 505,303 arthroplasties were included. The dose-response analysis showed a significant non-linear relationship between BMI and the risk of PJI (Pnon-linearity <0.001). Patients following THA (RR, 1.489; 95% CI, 1.343-1.651; P<0.001) were more likely to suffer from PJI than patients following TKA. Furthermore, American Society of Anesthesiologists (ASA) score >= 3 (RR, 2.287; 95% CI, 1.650-3.170; P< 0.001), lung disease (RR, 1.484; 95% CI, 1.208-1.823; P<0.001) and diabetes (RR, 1.695; 95% CI, 1.071-2.685; P=0.024) were identified as risk factors for PJI, but male (RR, 1.649; 95% CI, 0.987-2.755; P=0.056) and hypertension (RR, 0.980; 95% CI, 0.502-1.916; P=0.954) were not recognized as risk factors for PJI. Conclusions: The J-shaped non-linear relationship demonstrated that increased BMI was associated with an increased risk for PJI after primary THA or TKA. Patients following THA were more likely to suffer from PJI than patients following TKA. Also, patients with ASA score >= 3, lung disease and diabetes have a higher risk of PJI. Gender and hypertension did not influence the incidence of PJI.