The role of C-reactive protein to procalcitonin ratio in detecting early periprosthetic joint infections after total joint arthroplasty

Background: Periprosthetic joint infection (PJI) is a severe complication following total joint arthroplasty (TJA), leading to significant morbidity and mortality. Early diagnosis is crucial for effective treatment. The C-reactive protein / procalcitonin (CRP / PCT) ratio has emerged as a potential biomarker for the early detection of PJIs. This study aims to evaluate the utility of the CRP / PCT ratio in diagnosing early-stage PJIs following total knee arthroplasty (TKA). Methods: A prospective cross-sectional study was conducted on 51 patients who underwent unilateral primary TKA between April 2021 and August 2021. Patients were classified into three groups: (1) those who developed an infection within the first month (acute phase), (2) those who developed an infection within the first year, and (3) those without infection. Inflammatory markers, including CRP, PCT, erythrocyte sedimentation rate (ESR), and white blood cell (WBC) count, were recorded at multiple postoperative time points. The CRP / PCT ratio was calculated and analyzed for its diagnostic performance. Results: Patients in Groups 1 and 2 exhibited significantly higher CRP and PCT levels compared to Group 3. The CRP / PCT ratio was notably elevated in infected patients, particularly on postoperative days 3 and 28 (p < 0.05). Additionally, ESR levels remained elevated at 6 and 12 months in infected patients. These findings suggest that the CRP / PCT ratio may serve as an early indicator of PJI and offer superior diagnostic accuracy compared to each biomarker alone. Conclusions: The CRP / PCT ratio appears to be a promising biomarker for the early detection of PJI following TKA. Monitoring this ratio may facilitate timely intervention and potentially reduce morbidity associated with delayed diagnosis. Further studies with larger sample sizes are needed to validate these findings and optimize diagnostic protocols.