New Review Targets Better Infection Diagnosis in Inflammatory Arthritis Patients

Diagnosing an infection around an artificial hip or knee is one of the trickier challenges in orthopaedic medicine, and it becomes even harder when the patient has an inflammatory form of arthritis. A team of researchers from Shaoxing, China, has now registered and published a detailed protocol for a systematic review and diagnostic test accuracy meta-analysis that will examine how well blood- and joint-fluid-based biomarkers perform in this specific population. The protocol, published in Frontiers in Medicine, sets out the methods for a study that has not yet been carried out, so it reports planned analyses rather than results.

The clinical problem the review will address is well described in the protocol itself. Periprosthetic joint infection, often abbreviated as PJI, can sometimes be difficult to diagnose in patients with inflammatory arthritis because autoimmune disease activity and immunomodulatory treatment can alter both systemic and synovial inflammatory responses. In practical terms, the blood tests and synovial fluid markers that orthopaedic surgeons rely on may behave differently in someone whose immune system is already activated by rheumatoid arthritis or a related condition, or whose immune system is deliberately suppressed by medication.

Most of the diagnostic thresholds in current use were derived predominantly from patients with osteoarthritis. According to the protocol’s background section, this mismatch may produce false-positive or false-negative classifications when the same cut-offs are applied to people with inflammatory arthritis. The authors argue that recent rheumatoid arthritis-specific cohorts and studies of synovial host-response biomarkers have expanded the evidence base beyond what was available to earlier reviews, making a fresh synthesis timely.

The planned review will focus on studies evaluating serum, plasma, whole-blood, or synovial host-response biomarkers for hip or knee periprosthetic joint infection in adults with inflammatory arthritis.

The team will search MEDLINE, Embase, Web of Science, Scopus, CINAHL, the Cochrane Library, and four Chinese databases, CNKI, Wanfang, VIP, and SinoMed, from inception without language restrictions. Two reviewers will independently screen records, extract data, and assess risk of bias and applicability using QUADAS-3, the current standard tool for diagnostic accuracy studies.

For studies that directly compare the accuracy of two or more biomarkers in the same patients, the protocol specifies an adapted QUADAS-C assessment, a companion tool designed for comparative diagnostic accuracy evidence.

The statistical plan is also laid out in detail. For each biomarker and each clinically coherent threshold group, the authors will synthesize paired sensitivity and specificity using bivariate random-effects models or hierarchical summary receiver operating characteristic models. Where the data permit, the team plans subgroup analyses, meta-regression, and sensitivity analyses examining threshold effects, reference-standard incorporation bias, joint type, infection chronicity, disease activity, and immunosuppressive therapy. Each of these factors could plausibly modify how a biomarker performs in inflammatory arthritis, but the protocol is careful to state that such analyses will only be run when the underlying data allow them.

The protocol is registered with PROSPERO under registration number CRD420261449928.

The stated aims of the review are threefold: to determine whether commonly used and emerging host-response biomarkers retain adequate diagnostic performance in inflammatory arthritis, to identify candidate population-specific thresholds that require prospective external validation, and to clarify where the evidence is insufficient for clinical implementation. Because this is a protocol, no findings on biomarker accuracy yet exist, and any candidate thresholds the review eventually proposes would still need validation in new prospective cohorts before they could inform patient care. The article was received on 13 July 2026 and accepted on 5 October 2026, and the work is led by Jixin Chen, Qinxin Zhou, Yongming Zhang, Jianliang Chen, Xiaodong Zheng, and Feng Ye, based at two Shaoxing hospitals of traditional Chinese medicine.

Subject of Research: A protocol for a systematic review and diagnostic accuracy meta-analysis of host-response biomarkers for prosthetic joint infection in inflammatory arthritis.

Article Title: Diagnostic performance and reported diagnostic thresholds of serum and synovial host-response biomarkers for periprosthetic joint infection in patients with inflammatory arthritis: protocol for a systematic review and diagnostic test accuracy meta-analysis

Article References: Chen, J., Zhou, Q., Zhang, Y., Chen, J., Zheng, X., & Ye, F. (2026). Diagnostic performance and reported diagnostic thresholds of serum and synovial host-response biomarkers for periprosthetic joint infection in patients with inflammatory arthritis: protocol for a systematic review and diagnostic test accuracy meta-analysis. Frontiers in Medicine, 13, Article 1936572. https://doi.org/10.3389/fmed.2026.1936572

Image Credits: AI Generated

DOI: 10.3389/fmed.2026.1936572

Keywords: periprosthetic joint infection, inflammatory arthritis, diagnostic accuracy, biomarkers, systematic review, meta-analysis, synovial fluid, rheumatoid arthritis, QUADAS-3, GRADE, PROSPERO, orthopaedics