Rheumatology Department, Royal North Shore Hospital and Institute of Bone and Joint Research, Kolling Institute, University of Sydney, Sydney, New South Wales, Australia.
School of Public Health, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia; Faculty of Science and Engineering, Macquarie University, Sydney, New South Wales, Australia.
Osteoarthritis Cartilage. 2019 Feb;27(2):257-265. doi: 10.1016/j.joca.2018.09.015. Epub 2018 Oct 19.
There is significant variability in the trajectory of structural progression across people with knee osteoarthritis (OA). We aimed to identify distinct trajectories of femorotibial cartilage thickness over 2 years and develop a prediction model to identify individuals experiencing progressive cartilage loss.
We analysed data from the Osteoarthritis Initiative (OAI) (n = 1,014). Latent class growth analysis (LCGA) was used to identify trajectories of medial femorotibial cartilage thickness assessed on magnetic resonance imaging (MRI) at baseline, 1 and 2 years. Baseline characteristics were compared between trajectory-based subgroups and a prediction model was developed including those with frequent knee symptoms at baseline (n = 686). To examine clinical relevance of the trajectories, we assessed their association with concurrent changes in knee pain and incidence of total knee replacement (TKR) over 4 years.
The optimal model identified three distinct trajectories: (1) stable (87.7% of the population, mean change -0.08 mm, SD 0.19); (2) moderate cartilage loss (10.0%, -0.75 mm, SD 0.16) and (3) substantial cartilage loss (2.2%, -1.38 mm, SD 0.23). Higher Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) pain scores, family history of TKR, obesity, radiographic medial joint space narrowing (JSN) ≥1 and pain duration ≤1 year were predictive of belonging to either the moderate or substantial cartilage loss trajectory [area under the curve (AUC) 0.79, 95% confidence interval (CI) 0.74, 0.84]. The two progression trajectories combined were associated with pain progression (OR 1.99, 95% CI 1.34, 2.97) and incidence of TKR (OR 4.34, 1.62, 11.62).
A minority of individuals follow a progressive cartilage loss trajectory which was strongly associated with poorer clinical outcomes. If externally validated, the prediction model may help to select individuals who may benefit from cartilage-targeted therapies.
膝关节骨关节炎（OA）患者的结构进展轨迹存在显著差异。我们旨在确定 2 年内股胫软骨厚度的不同轨迹，并建立预测模型以识别发生进行性软骨丢失的个体。
我们分析了来自骨关节炎倡议（OAI）的数据（n=1014）。使用潜在类别增长分析（LCGA）来确定基线、1 年和 2 年时磁共振成像（MRI）评估的内侧股胫软骨厚度的轨迹。比较基于轨迹的亚组之间的基线特征，并建立预测模型，包括基线时有频繁膝关节症状的患者（n=686）。为了检验轨迹的临床相关性，我们评估了它们与 4 年内膝关节疼痛的同时变化和全膝关节置换（TKR）发生率之间的关系。
最佳模型确定了三个不同的轨迹：（1）稳定（人群中的 87.7%，平均变化-0.08mm，SD 0.19）；（2）中度软骨丢失（10.0%，-0.75mm，SD 0.16）和（3）大量软骨丢失（2.2%，-1.38mm，SD 0.23）。更高的西部安大略省和麦克马斯特大学骨关节炎指数（WOMAC）疼痛评分、TKR 家族史、肥胖、放射学内侧关节间隙狭窄（JSN）≥1 和疼痛持续时间≤1 年与属于中度或大量软骨丢失轨迹相关[曲线下面积（AUC）0.79，95%置信区间（CI）0.74，0.84]。两个进展轨迹合并与疼痛进展（OR 1.99，95%CI 1.34，2.97）和 TKR 发生率（OR 4.34，1.62，11.62）相关。
少数人遵循进行性软骨丢失轨迹，与较差的临床结局密切相关。如果经过外部验证，该预测模型可能有助于选择可能受益于软骨靶向治疗的个体。
