Normal CRP and WBC values in total hip arthroplasty (THA) with signs of loosening. Do we need a joint aspiration?

Abstract

Purpose: Overall Total hip arthroplasty (THA) is a very successful procedure. However, in case of complication dedicated management is required. Two major complications of THA failures are aseptic loosening (AL) and periprosthetic joint infection (PJI). The primary hypothesis of this study was that joint aspirations in patients with signs of loosening after THA are capable to detect PJI in suspected AL with negative serologic testing. Methods: In this study a total of 108 symptomatic patients with radiographic signs of prosthetic loosening and hip pain in THA were included. Based on a standardized algorithm all patients underwent serological testing followed by joint aspiration preoperatively. Intraoperatively harvested samples were subjected to microbiological testing and served as the gold standard in differential diagnosis. Demographics, as well as the results of serologic and microbiological testing were collected from the medical records. Results: Of the included patients 85 were finally diagnosed with an AL and 23 with PJI. Within the patients with PJI 13 (56%) patients demonstrated elevated CRP and WBC counts, as well as positive synovial cultures after joint aspiration. In ten patients (44%) diagnosed with PJI neither CRP nor WBC were abnormal. Conclusion:The diagnosis of PJI can be difficult in THA with radiographic signs of loosening. Clinical features including pain, fever, and local sings of infection are uncommon especially a long period after index operation. First-line screening testing relies on serological evaluation of CRP and WBC. However, normal CRP and WBC values cannot rule out a PJI. These cases can be detected by joint aspiration and synovial cultures reliably.

Aseptic Loosening after THA and TKA - Do gender, tobacco use and BMI have an impact on implant survival time?

“…These controversial results may be a result of different follow-up-times and inhomogeneous study designs. In contrast to most other studies, in the current study all THA and TKA patients were undergoing the same diagnostic algorithm for AL according to Schiffner et al 15 The impact of tobacco use on the incidence of AL and implant survival time is discussed controversially in literature. Meldrum et al 17 reported a significantly higher rate of component revision with shorter survival time in THA in smokers.…”

“…The diagnosis of AL was suspected in cases with a periimplant lucency of greater than 2 mm 14 in serial anteroposterior and lateral radiographs in absence of local or systemic signs of an infection. Diagnosis was confirmed by the serologic parameter CRP within normal https://doi.org/10.1016/j.jor.2019.03.018 Received 27 January 2019; Accepted 31 March 2019 T limits in combination with a negative result of a microbiologic testing of a synovial fluid aspiration according to Schiffner et al 15 These tests were performed in all patients. To allow a retrospective control of the diagnosis soft tissue samples were obtained in all cases during the revision surgery and were subjected to a microbiological analysis.…”

Current Clinical Methods for Detection of Peri-Prosthetic Joint Infection

“…With regard to MSIS minor criteria, current research demonstrates both promising and disappointing results. Methods using the detection of biomarkers indicative of an inflammatory response to an infection can be inconclusive at differentiating PJI from aseptic loosening [18,19]. Such biomarkers, measured in the serum and synovial fluid, include CRP detection, leukocyte counts and differential, and measurement of interleukin (IL)-6 levels.…”

“…Studies have shown that CRP cannot stand alone as a diagnostic tool for distinguishing PJI, but it is helpful when paired with other inflammatory markers. Schiffner et al [19] found that at the 1 mg/dL threshold for CRP, there was a 65% sensitivity and a 56% specificity. When CRP is measured from synovial fluid, sensitivity and specificity both increase to 88% and 82%, respectively, suggesting that synovial CRP may be a better diagnostic test for PJI than serum CRP.…”

“…When CRP is measured from synovial fluid, sensitivity and specificity both increase to 88% and 82%, respectively, suggesting that synovial CRP may be a better diagnostic test for PJI than serum CRP. Alone, however, regardless of source, CRP is not specific enough to distinguish PJI from aseptic loosening [19,43]. Despite this, CRP is a useful complementary test, because patients with higher CRP levels had significant correlation to having more positive intra-operative cultures [44].…”