David J Hunter

Objective To investigate which magnetic resonance imaging (MRI)–based articular pathologies are predictive of subsequent medial femorotibial compartment quantitative cartilage thickness loss and therefore suitable for enrichment of clinical trials with participants showing a high likelihood for structural progression. Methods Semiquantitative MRI Osteoarthritis Knee Score (MOAKS) assessments at baseline and quantitative cartilage thickness measurements at baseline and year‐2 follow‐up were performed in 599 participants (age 62 years; body mass index 31 kg/m 2 ; 59% female) from the Osteoarthritis Initiative–based Foundation for the National Institutes of Health Osteoarthritis Biomarkers Consortium. Knees were classified as medial femorotibial compartment (MFTC) progressors or nonprogressors based on MFTC cartilage thickness change (smallest detectable change threshold −111 μm). Logistic regression was used to investigate the association between baseline presence and severity of MFTC MOAKS pathologies with subsequent MFTC progression. The standardized response mean (SRM) was computed to estimate the sensitivity to change that can be achieved when selecting knees based on MOAKS pathologies. Results Presence of MFTC MOAKS cartilage damage (odds ratio [OR] 2.77 [95% confidence interval (95% CI) 1.76, 4.36]), MFTC bone marrow lesions (OR 2.69 [95% CI 1.89, 3.83]), medial meniscus extrusion or damage (OR 2.21 [95% CI 1.37, 3.55]), as well as MOAKS severity subscales for cartilage and meniscus damage were associated with subsequent progression. The SRM was greater in knees with than in knees without the presence of these pathologies and was associated with the severity of those pathologies. Conclusion MRI‐based grading of articular pathologies makes it possible to specifically select progressor knees suitable for inclusion in clinical trials but also to identify knees in which treatment is not indicated (e.g., knees without cartilage damage despite presence of radiographic osteoarthritis).

Objective Class III obesity (body mass index >40 kg/m 2 ) is associated with higher complications following total knee replacement (TKR), and weight loss is recommended. We aimed to establish the cost‐effectiveness of Roux‐en‐Y gastric bypass (RYGB), laparoscopic sleeve gastrectomy (LSG), and lifestyle nonsurgical weight loss (LNSWL) interventions in knee osteoarthritis patients with class III obesity considering TKR. Methods Using the Osteoarthritis Policy model and data from published literature to derive model inputs for RYGB, LSG, LNSWL, and TKR, we assessed the long‐term clinical benefits, costs, and cost‐effectiveness of weight‐loss interventions for patients with class III obesity considering TKR. We assessed the following strategies with a health care sector perspective: 1) no weight loss/no TKR, 2) immediate TKR, 3) LNSWL, 4) LSG, and 5) RYGB. Each weight‐loss strategy was followed by annual TKR reevaluation. Primary outcomes were cost, quality‐adjusted life expectancy (QALE), and incremental cost‐effectiveness ratios (ICERs), discounted at 3% per year. We conducted deterministic and probabilistic sensitivity analyses to examine the robustness of conclusions to input uncertainty. Results LSG increased QALE by 1.64 quality‐adjusted life‐years (QALYs) and lifetime medical costs by $17,347 compared to no intervention, leading to an ICER of $10,600/QALY. RYGB increased QALE by 0.22 and costs by $4,607 beyond LSG, resulting in an ICER of $20,500/QALY. Relative to immediate TKR, LSG and RYGB delayed and decreased TKR utilization. In the probabilistic sensitivity analysis, RYGB was cost‐effective in 67% of iterations at a willingness‐to‐pay threshold of $50,000/QALY. Conclusion For patients with class III obesity considering TKR, RYGB provides good value while immediate TKR without weight loss is not economically efficient.