The impact of a significant weight loss on inflammation assessed on DCE-MRI and static MRI in knee osteoarthritis: a prospective cohort study.

OBJECTIVE: To study the impact of weight loss on inflammation in individuals with overweight and knee osteoarthritis (OA) using both static- and dynamic contrast-enhanced (DCE)-MRI and assess the association of these changes to pain. DESIGN: Individuals with overweight (BMI > 27) and knee OA were examined before and after a >5% weight loss over 8 weeks (ClinicalTrials.gov NCT02905864). Using 3-T MRI, inflammation was quantified from non-contrast enhanced static-MRI according to MOAKS and contrast enhanced static MRI according to BLOKS and 11-point whole-knee synovitis score. DCE-MRI was used to assess the inflammation in the infra patellar fat pad (IPFP). Pain was assessed using KOOS. RESULTS: Complete data were available in 117 participants with a mean age of 60 years, BMI of 35 kg/m2 and KOOS pain score of 64. Mean weight loss was 12 kg and KOOS pain was improved by 13 points at follow-up. Change in inflammation was not associated with weight loss in static MRI. None of the MRI variables correlated with the change in KOOS pain. CONCLUSION: Weight loss did not induce a significant change in inflammation in individuals with overweight and OA. The significant clinical beneficial effect of weight loss on knee pain in individuals with overweight and knee OA seems uncoupled to changes in imaging markers of synovitis.

The effects of weight loss on imaging outcomes in osteoarthritis of the hip or knee in people who are overweight or obese: a systematic review.

OBJECTIVE: To evaluate the structural effects of weight loss on hip or knee osteoarthritis (OA) and to summarize which structural joint pathologies have been examined and the evidence for the outcome measurement instruments applied. DESIGN: Based on a pre-specified protocol (available: PROSPERO CRD42017065263), we conducted a systematic search of the bibliographic databases, Medline, Embase and Web of Science identifying longitudinal articles reporting the effects of weight loss on structural imaging outcomes in OA of the hip or knee in people who are overweight or obese. RESULTS: From 1625 potentially eligible records, 14 articles (from 6 cohorts) were included. 2 cohorts were derived from RCTs. Evaluated pathologies were: articular cartilage (n = 7), joint space width (n = 3), bone marrow lesions (n = 5), synovitis (n = 2), effusion (n = 1), meniscus (n = 3), bone marrow density (n = 1) and infrapatellar fat pad (IPFP; n = 2). Cartilage showed conflicting results when evaluating cartilage thickness by direct thickness measurements. Compositional dGEMRIC and T2 mapping measures in early knee OA showed trends towards reduced cartilage degeneration. Joint space width on conventional radiographs showed no change. Weight loss reduced the size of the IPFP. Synovitis and effusion were not affected. Following weight loss DXA showed bone loss at the hip. CONCLUSION: We did not find consistent evidence of the effects of weight loss on OA structural pathology in people who are overweight or obese. There is a need to achieve consensus on which structural pathologies and measurements to apply in weight loss and OA research.