The Role of Perioperative C-Reactive Protein Measurement in Primary Hip and Knee Arthroplasty

C-reactive protein (CRP) is an established component of perioperative diagnostics in primary hip and knee arthroplasty; however, its clinical value and the validity of commonly used thresholds remain controversial. The aim of this study was to assess the pre- and postoperative handling of CRP at certified German arthroplasty centres (EPZ) and to critically appraise its clinical relevance.

A 12-item internet-based questionnaire on the perioperative use of CRP was mailed to all 659 centres certified in April 2024; 134 centres participated anonymously. In 2023, these centres had performed a total of 91793 primary hip and knee arthroplasties.

Preoperatively, 130 of 134 centres (97.0%) determined CRP routinely. The thresholds applied varied considerably (< 5 mg/l: 48 centres; < 10 mg/l: 69; > 10 mg/l: 11). When the threshold was exceeded, 78 centres primarily referred patients for external evaluation, whereas 39 performed the work-up themselves. Most centres considered the probability of identifying a treatable focus to be low; when no focus was found, 67 of 130 centres proceeded with surgery nonetheless. Postoperatively, 126 centres determined CRP, but only 93 considered this necessary. The timing varied markedly, with 40.5% measuring as early as the first postoperative day. Additional inflammatory parameters were rarely obtained. Only seven centres based the indication for revision primarily on the CRP value.

CRP is used frequently but heterogeneously in perioperative diagnostics. Given its limited specificity, particularly for mildly elevated values, and the well-known physiological postoperative increase, routine postoperative CRP measurement appears dispensable in uncomplicated cases. A standardised checklist and a stronger clinical focus could render diagnostics more efficient.