Die Bedeutung des C-reaktiven Proteins in der Diagnostik von postoperativen periprothetischen Infektionen nach Primärimplantation von Hüftgelenksendoprothesen

The primary objective of this doctoral thesis was to develop a cost-efficient diagnostic tool for the detection of postoperative periprosthetic joint infection (PJI) following primary total hip arthroplasty (THA). Additionally, risk factors for the development of PJI as well as postoperative laboratory parameters and their kinetic behavior were evaluated with respect to early infection detection. Particular focus was placed on the postoperative kinetics of C-reactive protein (CRP) as a key inflammatory marker. In this retrospective study, biometric, clinical, and laboratory data from 802 patients were analyzed. After exclusion of 94 patients due to quality control criteria, 708 patients were included in the final statistical analysis. The cohort consisted predominantly of female patients (54.7%), and a pronounced imbalance was observed between the non-infection group (98.9%) and the infection group (1.1%). Male sex was identified as a significant risk factor for the development of postoperative PJI, potentially related to a higher prevalence of smoking. Prolonged length of hospital stay was also associated with an increased infection risk, possibly reflecting nosocomial infections and pre-existing comorbidities. Among the analyzed laboratory parameters, only serum CRP demonstrated significant diagnostic relevance. A postoperative second peak or failure-to-decline pattern in CRP levels occurred significantly more frequently in patients with PJI and was therefore incorporated into predictive modeling. Using a multinomial logistic regression model including five variables, PJI was predicted with a sensitivity of 87.5% and a specificity of 78.85%. These values exceeded those reported in comparable studies relying primarily on laboratory parameters alone. The proposed model represents a cost-efficient diagnostic approach for estimating postoperative PJI following THA. Incorporation of synovial leukocyte count may further improve diagnostic accuracy.