The value of synovial biopsy, joint aspiration and C-reactive protein in the diagnosis of late peri-prosthetic infection of total knee replacements

Abstract

We analysed the serum C-reactive protein level, synovial fluid obtained by joint aspiration and five synovial biopsies from 145 knee replacements prior to revision to assess the value of these parameters in diagnosing late peri-prosthetic infection. Five further synovial biopsies were used for histological analysis. Samples were also obtained during the revision and incubated and analysed in an identical manner for 14 days. A total of 40 total knee replacements were found to be infected (prevalence 27.6%). The aspiration technique had a sensitivity of 72.5% (95% confidence interval (CI) 58.7 to 86.3), a specificity of 95.2% (95% CI 91.2 to 99.2), a positive predictive value of 85.3% (95% CI 73.4 to 100), a negative predictive value of 90.1% (95% CI 84.5 to 95.7) and an accuracy of 89%. The biopsy technique had a sensitivity of 100%, a specificity of 98.1% (95% CI 95.5 to 100), a positive predictive value of 95.2% (95% CI 88.8 to 100), a negative predictive value of 100% and an accuracy of 98.6%. C-reactive protein with a cut-off-point of 13.5 mg/l had a sensitivity of 72.5% (95% CI 58.7 to 86.3), a specificity of 80.9% (95% CI 73.4 to 88.4), a positive predictive value of 59.2% (95% CI 45.4 to 73.0), a negative predictive value of 88.5% (95% 81.0 to 96.0 CI) and an accuracy of 78.1%. We found that biopsy was superior to joint aspiration and C-reactive protein in the diagnosis of late peri-prosthetic infection of total knee replacements.

Is There a Role for Tissue Biopsy in the Diagnosis of Periprosthetic Infection?

“…The serum level of CRP is regarded as an important diagnostic parameter and has a high sensitivity [59]. However, the specificity is generally lower, especially when patients with rheumatoid arthritis are included [20,25,65], and it does not identify the microorganism in question. Aspiration and biopsy offer the only chance of identifying the infective microorganism preoperatively [9,23,49,50].…”

“…However, Fink et al [20] examined the knee arthroscopically after biopsies were obtained and did not observe any damage. We observed no complications or technical problems with the use of the Tru-Cut needle.…”

“…In a study of 145 TKAs planned for revision surgery attributable to component loosening, Fink et al [20] showed that preoperative synovial biopsy, obtained using an arthroscopic biopsy forceps, was superior to joint aspiration for diagnosis of periprosthetic infection. Aspiration had a sensitivity of 72.5% and specificity of 95.2%.…”

“…However, the sensitivity of these tests reportedly varies from 12% to 100% (Table 1). Two studies reported a superiority of tissue biopsy over aspiration for diagnosis of periprosthetic infections in TKA [20,22]. However, one comparative study suggests tissue biopsy in THA offers no advantage over aspiration and should be avoided because it is a more invasive procedure [66].…”

Percutaneous interface biopsy in dry-aspiration cases of chronic periprosthetic joint infections: A technique for preoperative isolation of the infecting organism

“…Some authors have used synovial biopsy, obtained by various techniques, in an attempt to improve outcomes, but with inconsistent results [17][18][19].…”