Multidisciplinary Diagnostic Algorithm for Evaluation of Patients Presenting with a Prosthetic Problem in the Hip or Knee:A Prospective Study

The predominant indications for revision surgery after total hip (THA) or knee arthroplasty (TKA) are an aseptic failure (AF) and prosthetic joint infection (PJI). Accurate diagnosis is crucial. Therefore, we evaluated prospectively a multidisciplinary diagnostic algorithm including multi-modal radionucleid imaging (RNI) and extended microbiological diagnostics. If the surgeon suspected PJI or AF, revision surgery was performed with multiple samples obtained in parallel for special culture procedures and later molecular analyses. Alternatively, if the underlying cause was not evident, RNI was scheduled comprising 99Tc—HDP SPECT/CT, 111In-labeled white blood cells combined with 99Tc-nanocoll bone marrow SPECT/CT, and 18F-FDG PET/CT. A multidisciplinary clinical team made a recommendation on the indication for a diagnostic procedure guided by RNI images or revision surgery. A total of 156 patients with 163 arthroplasties were included. Fifty-five patients underwent RNI. In all, 118 revision surgeries were performed in 112 patients: 71 on the indication of AF and 41 revision of PJI. Thirty-four patients were concluded with chronic pain, and revision surgery refrained. The effective median follow-up period was 13 months. A structured approach offered by the algorithm was useful for the clinician in the evaluation of patients with a failing TKA or THA. Surgical revision was possibly obviated in approximately 20% of patients where an explanation or cause of failure was not found. The algorithm served as an effective tool

Differential contributions of specimen types, culturing, and 16S rRNA sequencing in diagnosis of prosthetic joint infections

ABSTRACT Prosthetic joint failure is mainly caused by infection, aseptic failure (AF), and mechanical problems. Infection detection has been improved with modified culture methods and molecular diagnostics. However, comparisons between modified and conventional microbiology methods are difficult due to variations in specimen sampling. In this prospective, multidisciplinary study of hip or knee prosthetic failures, we assessed the contributions of different specimen types, extended culture incubations, and 16S rRNA sequencing for diagnosing prosthetic joint infections (PJI). Project specimens included joint fluid (JF), bone biopsy specimens (BB), soft-tissue biopsy specimens (STB), and swabs (SW) from the prosthesis, collected in situ , and sonication fluid collected from prosthetic components (PC). Specimens were cultured for 6 (conventional) or 14 days, and 16S rRNA sequencing was performed at study completion. Of the 156 patients enrolled, 111 underwent 114 surgical revisions (cases) due to indications of either PJI ( n = 43) or AF ( n = 71). Conventional tissue biopsy cultures confirmed PJI in 28/43 (65%) cases and refuted AF in 3/71 (4%) cases; one case was not evaluable. Based on these results, minor diagnostic adjustments were made. Fourteen-day cultures of JF, STB, and PC specimens confirmed PJI in 39/42 (93%) cases, and 16S rRNA sequencing confirmed PJI in 33/42 (83%) cases. One PJI case was confirmed with 16S rRNA sequencing alone and five with cultures of project specimens alone. These findings indicated that JF, STB, and PC specimen cultures qualified as an optimal diagnostic set. The contribution of sequencing to diagnosis of PJI may depend on patient selection; this hypothesis requires further investigation. </jats:p