Total Knee Arthroplasty: Diagnostic Accuracy of Patterns of Synovitis at MR Imaging

Abstract

Purpose To determine the diagnostic accuracy of magnetic resonance (MR) imaging for differentiating synovial patterns in patients with total knee arthroplasty (TKA), whether diagnostic accuracy differs in index versus revision TKA, and interobserver and intraobserver reliability for assessment of synovial patterns at MR imaging. Materials and Methods This retrospective cross-sectional study included 108 consecutive patients with TKAs who underwent MR imaging within 1 year prior to revision surgery from 2012 to 2014. Institutional review board approval was obtained, with waiver of the need to obtain informed consent. MR images were reviewed, and cases were qualitatively categorized by the appearance of the synovium as one of the following: frondlike and hypertrophied (particle-induced synovitis), lamellated and hyperintense (infection), and a homogeneous effusion with the signal intensity of fluid (nonspecific synovitis). The MR imaging appearance was compared with surgical and microbiology reports as the reference standard to determine the sensitivity, specificity, and positive and negative predictive values for the index TKA and revision TKA cohorts. Results For all patients combined, MR imaging had 0.907-0.930 sensitivity and 0.723-0.738 specificity for a surgical diagnosis of complications related to polyethylene wear (including osteolysis and loosening); 0.652-0.783 sensitivity and 0.976-0.988 specificity for infection; and 0.643-0.667 sensitivity and 0.894-0.939 specificity for stiffness, instability, and nonspecific pain. Diagnostic accuracy was higher in the index TKA cohort than in the revision TKA cohort. Interobserver and intraobserver reliabilities were almost perfect (κ = 0.82 and κ = 0.83, respectively). Conclusion MR imaging can help distinguish qualitative differences in the appearance of the synovium in TKA between particle-induced synovitis, infection, and nonspecific synovitis, with almost perfect interobserver and intraobserver reliability. Diagnostic accuracy is higher for index TKA than for revision TKA. RSNA, 2016.

MRI as Diagnostic Modality for Analyzing the Problematic Knee Arthroplasty: A Systematic Review

“…Periprosthetic joint infections were associated with signs of lamellated hyperintense synovitis on MRI. Almost excellent reproducibility results were found regarding lamellated hyperintense synovitis, with an interrater reproducibility of (K = 0.82 and K = 0.82) and intrarater reproducibility of (K = 0.83 and K = 0.89) . Loosening was evaluated in two studies by assessing the implant–bone interface.…”

“…First, MRI to identify periprosthetic joint infection based on MRI findings of hypertrophied synovitis compared with the reference standard was evaluated by two studies of adequate quality. Diagnostic properties were found in terms of sensitivity and specificity (0.89 and 0.89; 0.96 and 0.71) with "almost excellent" reliability . Nonetheless, it should be noted that both TKA studies were conducted by the same research group.…”

“…This made evaluation with the reference standard possible. However, it induces selection bias, and leads to the possibility that sensitivity and specificity values were overestimated . Moreover, if image observers had known that there was always some pathology to find on the MRI, this certainly may have led them to overestimate the inter‐ and intrareproducibility values.…”

“…19,25,29,30,34 Criterion validity was assessed by comparing MRI findings with perioperative findings. 10,19,25,29,[31][32][33][35][36][37] Construct validity was determined by using different standards as comparators, such as CT, 30,34 knee pain, 38 and healthy controls. 26 Due to the retrospective designs of the included studies, which is thought to increase susceptibility to selection bias, none of the retrospective studies scored "low risk" for the patient selection bias by QUADAS-2.…”

MRI of synovitis and joint fluid

“…A study by Li et al, utilizing surgical pathology and microbiology as a reference, found that MRI could distinguish between particle-induced synovitis, infection, and nonspecific synovitis, with almost perfect reliability and diagnostic accuracy, which was higher for index TKA than for a revision TKA. 99 MRI Assessment of Other Miscellaneous Synovial Diseases PSORIATIC ARTHRITIS (PSA). PsA is a chronic, systemic inflammatory disease, which is histologically characterized by less pronounced hyperplasia of the intimal lining layer, marked vascularity, and a synovial infiltrate composed of B cells, plasma cells, dendritic cells, CD 163+ macrophages, larger influx of neutrophils, and fewer synovial T cells compared with RA.…”