Trend of Perioperative CRP (C-Reactive Protein) Levels in Non-Infected Total Knee Arthroplasty.

The aim of this prospective study was to define the perioperative trend of C-reactive protein (CRP) in non-infected total knee arthroplasty (TKA). CRP was evaluated in 42 patients the day before surgery and 4 and 30 days after surgery. Functional and radiological evaluation was scheduled for 3, 6, and 12 months after surgery. Preoperatively, the median CRP was 3.2 mg/L (IQR,3.2-4.2) (reference range, 0-5 mg/L); 4 and 30 days after surgery, it measured 57.6 mg/L (IQR,36.1-96.4) and 5.3 mg/L (IQR,3.0-11.8), respectively. There were significant differences between the CRP preoperatively and 4 days after surgery (p<0.001) and between CPR levels 4 and 30 days after surgery (p<0.001) but not between CRP values preoperatively and 30 days after surgery (p=0.181). Higher preoperative CRP was associated to heart disease and chronic renal failure (r=0.329, p=0.036, and r=0.437, p=0.004, respectively). Four days after surgery, higher CRP was associated to older patients (r=0.311, p=0.048). In summary, 30 days after primary non-infected TKA, CRP levels were comparable to preoperative values. Older age and comorbidities should be carefully evaluated using postoperative CRP as diagnostic marker for the early detection of infection.