Quantification of intra-articular fibrosis in patients with stiff knee arthroplasties using metal-reduction MRI

Abstract

Aims Stiffness is a common complication after total knee arthroplasty (TKA). Pathogenesis is not understood, treatment options are limited, and diagnosis is challenging. The aim of this study was to investigate if MRI can be used to visualize intra-articular scarring in patients with stiff, painful knee arthroplasties. Methods Well-functioning primary TKAs (n = 11), failed non-fibrotic TKAs (n = 5), and patients with a clinical diagnosis of fibrosis 1 (n = 8) underwent an MRI scan with advanced metal suppression (Slice Encoding for Metal Artefact Correction, SEMAC) with gadolinium contrast. Fibrotic tissue (low intensity on T1 and T2, low-moderate post-contrast enhancement) was quantified (presence and tissue thickness) in six compartments: supra/infrapatella, medial/lateral gutters, and posterior medial/lateral. Results Fibrotic tissue was identified in all patients studied. However, tissue was significantly thicker in fibrotic patients (4.4 mm ± 0.2 mm) versus non-fibrotic (2.5 mm ± 0.4 mm) and normal TKAs (1.9 mm ± 0.2 mm, p = < 0.05). Significant (> 4 mm thick) tissue was seen in 26/48 (54%) of compartments examined in the fibrotic group, compared with 17/30 (57%) non-fibrotic, and 10/66 (15%) normal TKAs. Although revision surgery did improve range of movement (ROM) in all fibrotic patients, clinically significant restriction remained post-surgery. Conclusion Stiff TKAs contain intra-articular fibrotic tissue that is identifiable by MRI. Studies should evaluate whether MRI is useful for surgical planning of debridement, and as a non-invasive measurement tool following interventions for stiffness caused by fibrosis. Revision for stiffness can improve ROM, but outcomes are sub-optimal and new treatments are required. Cite this article: Bone Joint J 2020;102-B(10):1331–1340.

Knee immobilization reproduces key arthrofibrotic phenotypes in mice

“…Evaluation of the joint via 3D imaging (i.e. MRI 42 or molecular approaches (e.g. RNA expression) would provide enhanced understanding of the architecture of periarticular fibrosis in mice.…”

Synovial inflammation in osteoarthritis progression

“…Fibrosis may contribute to joint stiffness and pain, which are the main symptoms in OA, but most of the clinical studies relate to postoperative synovial fibrosis. Intra-articular fibrosis can be detected by using MRI scans with advanced metal suppression and with gadolinium contrast 241 in patients with stiff and painful arthroplasty. Patients with diagnosed fibrosis 242 exhibit thicker tissue (4.4 mm ± 0.2 mm) than patients with a non-fibrotic phenotype (2.5 mm ± 0.4 mm) after total knee arthroplasty (1.9 mm ± 0.2 mm; P < 0.05) 241 .…”

“…Intra-articular fibrosis can be detected by using MRI scans with advanced metal suppression and with gadolinium contrast 241 in patients with stiff and painful arthroplasty. Patients with diagnosed fibrosis 242 exhibit thicker tissue (4.4 mm ± 0.2 mm) than patients with a non-fibrotic phenotype (2.5 mm ± 0.4 mm) after total knee arthroplasty (1.9 mm ± 0.2 mm; P < 0.05) 241 . A promising fibroblast radiotracer for PET, 18 F-labelled glycosylated FAPI, demonstrated highly specific uptake in bone structures and joints 243 and could aid in…”

Total Joint Replacement of Ankle, Knee, and Hip: How Do Patients Perceive Their Operative Outcomes at 10 Years?

“…Stiffness is a recognized complication post TKR surgery, Attard et al 2 in their recent article studying the cause for knee stiffness post TKR surgery have suggested intra-articular fibrosis to be an important contributing factor. Hinterman et al 10 in their article have suggested a preoperative diagnostic workup to be helpful in understanding the pathologic process behind the cause for stiffness following TAR surgery.…”