Surgical Site Infection After Total Knee Arthroplasty: Risk Factors in Patients With Timely Administration of Systemic Prophylactic Antibiotics

Background: Surgical site infection (SSI) after total knee arthroplasty (TKA) is a catastrophic complication. Administration of prophylactic antibiotics within 60 minutes before surgery is a well-established strategy to prevent SSI. The study is aimed to identify the risk factors for SSI regarding primary TKA in patients with timely administration of systemic prophylactic antibiotics. Methods: A retrospective review of patients with primary TKA between 2009 and 2013 was conducted. Patients who had prophylactic antibiotics administered after skin incision or >60 minutes before skin incision were excluded. Results: Of the 3152 patients enrolled, the incidence of SSI and deep-implant SSI was 1.52% and 0.79%, respectively. Charlson Comorbidity Index ≥3 was an independent risk factor for both SSI (odds ratio [OR], 2.34; 95% confidence interval [CI], 1.24-4.44, P = .01) and deep-implant SSI (OR, 3.46; 95% CI, 1.52-7.91, P < .01). Optimal dose of systemic antibiotics adjusted by patients' body weight for prophylaxis (OR, 0.29; 95% CI, 0.17-0.62, P < .01) and using antibiotic-laden bone cement (OR, 0.33; 95% CI, 0.17-0.64, P < .01) were significant protective factors for SSI. Meanwhile, using antibiotic-laden bone cement (OR, 0.31; 95% CI, 0.13-0.76, P = .01) also significantly decreased the risk of deep-implant SSI. Conclusion: Our findings highlight the importance of appropriate dosage of prophylactic antibiotics and use of antibiotic-laden cement in preventing SSI after primary TKA. For prevention of deep-implant SSI, using antibiotic-laden bone cement seems to be an advisable strategy.