Poor performance of open incisional biopsy for the microbiological diagnosis of periprosthetic knee joint infection

Abstract

The accurate preoperative diagnosis of periprosthetic joint infection (PJI) of total knee arthroplasty (TKA) can be difficult despite the use of a combination of serum and synovial markers. In such inconclusive cases, incisional open biopsy might be considered. This study investigates the usefulness of biopsies in patients with inconclusive diagnostic findings. We retrospectively identified 63 patients who underwent incisional biopsy for chronic PJI in the operation theatre following TKA revision between 2010 and 2018 after inconclusive preoperative diagnostics for PJI. In all cases, 5 independent biopsies were taken. Results from open biopsy for PJI were analyzed for diagnostic accuracy using the intraoperative results from following revision surgery as gold standard. 27 patients (43%) had a positive culture taken during biopsy. 15 cases (24%) met the diagnostic criteria for a chronic PJI. Most common organisms were Coagulase-negative staphylococci (67%) and Cutibacterium acnes (30%). Compared to the findings during revision surgery, biopsies showed a sensitivity of 47% and a specificity of 77% for PJI. Open incisional biopsy following inconclusive serum- and synovial diagnostics for low grade PJI may be considered for identification of microorganisms. Due to its low sensitivity and moderate specificity found in the present cohort, microbiological analysis should be combined with additional diagnostic markers and histological investigation.Level of Evidence. Retrospective cohort study (Level III).

Microbiological Advantages of Open Incisional Biopsies for the Diagnosis of Suspected Periprosthetic Joint Infections

“…In our cohort, we observed unexpected positive cultures in 7.89% of the patients, of which one patient needed additional revision surgeries due to persisting PJI. That rate was lower when compared to data of previous authors who found unexpected positive cultures in 23% of all cases [ 33 ]. Revision surgeries related to unexpected cultures were not reported by the authors.…”

“…A recent meta-analysis concluded that OIB is not superior to synovial fluid aspirations alone but contributes to the already existing diagnostic algorithms and improves diagnostic accuracy [ 34 ]. Since that analysis, few authors published results concerning the usage of OIB for the diagnosis of PJI [ 32 , 33 ]. Klaber et al assessed OIB as a diagnostic tool following two culture-negative aspirations in suspected PJI in THA and TKA [ 32 ].…”

“…A possible explanation for this may be the assessed endpoints, as Klaber et al investigated the predictability of OIB for the diagnosis of PJI according to the MSIS criteria, while we assessed the predictability of the causative germ spectrum by comparing OIB and revision surgery. Schwarze et al investigated the use of OIB in patients with TKA component loosening and inconclusive previous diagnostic results [ 33 ]. They observed a sensitivity of 47%, specificity of 77%, PPV of 39%, and NPV of 62%.…”

“…This might be explained by the surgical approach applied. In the cohort of Schwarze et al [ 33 ], supra-patellar mini-arthrotomy was adopted to collect samples, while we used an arthroscopic approach in all but one of the TKA patients. The latter approach potentially allows an easier sample collection in different representative regions when compared to mini-arthrotomies.…”

“…In order to enhance causative microorganism identification, open incisional joint biopsy (OIB) sampling of periprosthetic and synovial tissue can be considered when previous diagnostics remain inconclusive [ 15 ] or are not feasible due to dry tap aspirations. Although the role of OIB is currently discussed [ 32 , 33 , 34 ], fundamental clinical data remain limited. Therefore, this study aims to provide further evidence on the potential benefit of OIB in cases of inconclusive microbiological results in suspected PJI of THA and TKA.…”