Pelletier Jean-Pierre, Paiement Patrice, Abram François, Dorais Marc, Raynauld Jean-Pierre, Martel-Pelletier Johanne
University of Montreal Hospital Research Centre (CRCHUM), Osteoarthritis Research Unit, 900 Saint-Denis, Room R11.412A, Montreal, Quebec, H2X 0A9, Canada.
StatSciences Inc, Notre-Dame de-l'Île-Perrot, Notre-Dame, Quebec, Canada.
Arthritis Res Ther. 2025 Apr 26;27(1):98. doi: 10.1186/s13075-025-03513-y.
No established markers can effectively phenotype knee osteoarthritis (OA) patients into subgroups. Infrapatellar fat pad (IPFP) morphology data that can forecast disease symptoms, structural changes, and knee replacement (KR) are sparse and conflicting. This 96-month longitudinal exploratory study aimed to identify which IPFP morphological features were the most effective independent prognostic markers against these outcomes.
This longitudinal study analyzed 1075 target knees (one knee per participant) from the Osteoarthritis Initiative (OAI) progression cohort. Structural changes include cartilage, bone marrow lesions (BMLs), and joint effusion volumes assessed using automated and quantitative magnetic resonance imaging systems (MRI). The IPFP global and signal (hyper- and hypo-) intensity volumes and areas were assessed using MRI combined with a newly developed, fully automated neuron-driven technology. Symptoms were evaluated using WOMAC scores. Data on KR was obtained from the OAI database. Data were collected at baseline and 12, 24, 48 and 96 months and analyzed using a mixed model for repeated measures (MMRM) or ANCOVA.
The baseline characteristics were mild to moderate knee OA. Over time, disease symptoms (WOMAC), cartilage volume, IPFP global and hypointense signal volumes, and maximal and hypointense signal areas decreased (all p≤0.001). Joint effusion and hyperintense signal volume and area increased (both p≤0.001). Associations were found between IPFP morphologies at inclusion and changes in cartilage volume (hypointense and hyperintense volumes, 48, 96 months, p≤0.04), BML volume (global volume 48 months, p=0.05; hyperintense area, 12 months, p≤0.04), and effusion volume (hypointense volume 48 months and hyperintense volume 96 months, p≤0.05). At inclusion, smaller IPFP sizes (below median) were associated with cumulative KR at 96 months (global and hypointense volumes, p≤0.04 and maximum area, p=0.05).
This longitudinal exploratory study, leveraging a fully automated technology, highlights that i) IPFP volume (global and both signals) is superior to area metrics in predicting long-term structural changes in OA, and ii) smaller IPFP volume and area are linked with reduced need for KR. These findings provide new insights into the usefulness of IPFP morphology as a predictive biomarker of knee OA outcomes, offering a new approach to stratifying knee OA patients.
目前尚无既定的标志物能够有效地将膝骨关节炎（OA）患者分为不同亚组。能够预测疾病症状、结构变化和膝关节置换（KR）的髌下脂肪垫（IPFP）形态学数据稀少且相互矛盾。这项为期96个月的纵向探索性研究旨在确定哪些IPFP形态学特征是针对这些结局最有效的独立预后标志物。
这项纵向研究分析了来自骨关节炎倡议（OAI）进展队列的1075个目标膝关节（每位参与者一个膝关节）。结构变化包括使用自动化定量磁共振成像系统（MRI）评估的软骨、骨髓损伤（BMLs）和关节积液量。IPFP的总体积和信号（高信号和低信号）强度体积及面积通过MRI结合新开发的全自动神经元驱动技术进行评估。症状使用WOMAC评分进行评估。KR数据从OAI数据库中获取。在基线以及第12、24、48和96个月收集数据，并使用重复测量混合模型（MMRM）或协方差分析（ANCOVA）进行分析。
基线特征为轻度至中度膝OA。随着时间推移，疾病症状（WOMAC）、软骨体积、IPFP总体积和低信号体积以及最大和低信号面积均下降（所有p≤0.001）。关节积液以及高信号体积和面积增加（两者p≤0.001）。在纳入时的IPFP形态与软骨体积变化（低信号和高信号体积，第48、96个月，p≤0.04）、BML体积（总体积第48个月，p = 0.05；高信号面积，第个月，p≤0.04）和积液量（低信号体积第48个月和高信号体积第96个月，p≤0.05）之间存在关联。在纳入时，较小的IPFP尺寸（低于中位数）与96个月时的累积KR相关（总体积和低信号体积，p≤0.04；最大面积，p = 0.05）。
这项纵向探索性研究利用全自动技术强调，i）IPFP体积（总体积和两种信号）在预测OA长期结构变化方面优于面积指标，ii）较小的IPFP体积和面积与KR需求降低相关。这些发现为IPFP形态作为膝OA结局预测生物标志物的实用性提供了新见解，为膝OA患者分层提供了新方法。
