Obese and overweight individuals have greater knee synovial inflammation and associated structural and cartilage compositional degeneration: data from the osteoarthritis initiative

Abstract

Objective This work aims to study (i) the relationship between body mass index (BMI) and knee synovial inflammation using non-contrast-enhanced MRI and (ii) the association of synovial inflammation versus degenerative abnormalities and pain. Materials and methods Subjects with risk for and mild to moderate radiographic osteoarthritis were selected from the Osteoarthritis Initiative. Subjects were grouped into three BMI categories with 87 subjects per group: normal weight (BMI, 20-24.9 kg/m 2), overweight (BMI, 25-29.9 kg/m 2), and obese (BMI, ≥ 30 kg/m 2), frequency matched for age, sex, race, Kellgren-Lawrence grade, and history of knee surgery and injury. Semi-quantitative synovial inflammation imaging biomarkers were obtained including effusion-synovitis, size and intensity of infrapatellar fat pad signal abnormality, and synovial proliferation score. Cartilage composition was measured using T 2 relaxation time and structural abnormalities using the whole-organ magnetic resonance imaging score (WORMS). The Western Ontario and McMasters (WOMAC) Osteoarthritis Index was used for pain assessment. Intra-and inter-reader reproducibility was assessed by kappa values. Results Overweight and obese groups had higher prevalence and severity of all synovial inflammatory markers (p ≤ 0.03). Positive associations were found between synovial inflammation imaging biomarkers and average T 2 values, WORMS maximum scores and total WOMAC pain scores (p < 0.05). Intra-and inter-reader kappa values for imaging biomarkers were high (0.76-1.00 and 0.60-0.94, respectively). Conclusion Being overweight or obese was significantly associated with a greater prevalence and severity of synovial inflammation imaging biomarkers. Substantial reproducibility and high correlation with knee structural, cartilage compositional degeneration, and WOMAC pain scores validate the synovial inflammation biomarkers used in this study.

Presence of Magnetic Resonance Imaging–Defined Inflammation Particularly in Overweight and Obese Women Increases Risk of Radiographic Knee Osteoarthritis: The POMA Study

“…Concerning the second part of our analysis focusing on cases only regarding prevalence of inflammatory markers in the different subgroups, we found that up to 4 years prior to radiographic OA incidence, in general, the combined overweight/ obese subgroup did not show significantly increased rates of local inflammation, with the exception of effusion 2 years prior to radiographic OA incidence, while at 1 year prior, the association was close to being significant. A recent study also from the OAI reported a significantly greater prevalence and severity of synovial inflammation imaging biomarkers in knees of overweight and obese participants compared to those that have normal weight (15). In contrast to our study, however, almost 20% of included subjects exhibited radiographic OA grades 2 and 3, and for those without radiographic OA, it is not known how many developed radiographic OA at later time points.…”

Synovial inflammation in osteoarthritis progression

“…FLS isolated from patients with obesity with hip OA who underwent joint replacement surgery secrete higher amounts of IL-6 than FLS from lean patients, which was enhanced by crosstalk with chondrocytes via leptin 137 . Although patients with obesity have a higher prevalence and severity of synovial inflammation, as assessed by conventional MRI 25 , improvement in knee pain in patients with obesity with >20% weight loss at 1 year after dietary intervention or bariatric surgery was not mediated by a decrease in synovitis or bone marrow lesions (BMLs), as evaluated by MRI, but was partially explained by improvement in pressure pain threshold (at the patella and wrist) and depression score (CES-D) 138 . Furthermore, there was no noticeable improvement in BMLs (number and volume on MRI) or synovitis score after weight loss, which is in agreement with results of previous studies 139,140 .…”

“…More than 2 years before onset, patients with AKOA present with more pain, synovitis-effusion of larger volumes and signal alterations in the infrapatellar fat pad (IFP) compared with patients who develop typical knee OA 17,18 . MRI and ultrasonography have also been used to evaluate associations between synovitis and pain 5,[19][20][21][22][23][24][25][26][27] , finding that synovitis contributes to pain in OA. Of note, a study found that synovitis partially mediates the association between cartilage damage loss and worsening pain: each 0.1-mm loss of cartilage over 24 months translated to an increase in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain subscale score of 0.32 (95% CI 0.21-0.44) 28 .…”

Increased signal intensity, not volume variation of infrapatellar fat pad in knee osteoarthritis: A cross-sectional study based on high-resolution magnetic resonance imaging

“…However, this study has its potential limitations. First, a cross-sectional study could not speculate on causal relationships, and the modest sample size, which might hinder 22 Ann Anat 2020 Austria 3 mm Kanthawang et al 23 Skeletal Radiol 2020 USA 3 mm with 0.5 mm gap Okita et al 24 Knee 2019 Japan 1 mm Teichtahl et al 25 Arthritis Res Ther 2015 Australia 1.5 mm Pan et al 6 Ann Rheum Dis 2015 Australia 4 mm with 1 mm gap the ability to rule out the actual association between parameters. Second, the characteristics of groups are significantly different in age and height, which might reduce the comparability and produce bias as confounders.…”

“…Moreover, most of the MRI studies concerning the role of IPFP in OA only analyze IPFP in one aspect and use outdated MRI scanning with 1-3 mm slice thickness. 6,[21][22][23][24][25] In our study, we applied a high-resolution technique (with as little as a slice thickness of 0.35 mm and without inter-slice gap), calculated the IPFP maximal sagittal area and IPFP volume (relate to structural factors) and the quantitated signal intensity (relates to metabolism factors), compared the differences between healthy controls and OA patients, and analyze the relationship between IPFP and knee degeneration (or patellar maltracking) indicators to reveal which factor is more related to OA.…”