Eckstein Felix, Cotofana Sebastian, Wirth Wolfgang, Nevitt Michael, John Markus R, Dreher Donatus, Frobell Richard
Institute of Anatomy and Musculoskeletal Research, Paracelsus Medical University, Salzburg, Austria.
Arthritis Rheum. 2011 Aug;63(8):2257-67. doi: 10.1002/art.30414.
To investigate whether rates of cartilage loss differ in knees with frequent baseline pain versus those without pain, after adjustment for radiographic osteoarthritis (OA) stage.
One knee in each of 718 Osteoarthritis Initiative participants was examined: 310 with calculated Kellgren/Lawrence (K/L) grade 2, 299 with calculated K/L grade 3, and 109 with calculated K/L grade 4. Twelve-month change in (subregional) cartilage thickness was assessed by magnetic resonance imaging. Change in cartilage thickness in the central subregion of the weight-bearing medial femoral condyle and ordered value 1 (OV1) were selected as primary end points. Frequent knee symptoms were defined as pain, aching, or stiffness on most days of at least 1 month during the previous year.
The mean 12-month rate of change in cartilage thickness in the central subregion of the medial femoral condyle was -12 μm (standardized response mean [SRM] -0.15) in knees without pain (n = 146), -27 μm (SRM -0.25) in those with infrequent pain (n = 255), and -54 μm (SRM -0.32) in those with frequent pain (n = 317). Rates differed significantly between frequently painful knees and pain-free knees after adjustment for age, sex, body mass index, and calculated K/L grade (P = 0.011, R(2) = 2.6%, partial R(2) for frequent pain = 1.4%). Similar results were found in stratified samples of calculated K/L grade 2/calculated K/L grade 3 knees, and in analyses restricted to knees with consistent pain frequency between baseline and followup. OV1 results showed similar trends but were not significant.
Knees with frequent pain display greater rates of medial cartilage loss longitudinally than knees without pain, with or without adjustment or stratification for radiographic disease stage. Enrollment of participants with frequent knee pain in clinical trials can increase the observed rate of structural progression (i.e., cartilage loss) and sensitivity to change.
在对影像学骨关节炎（OA）分期进行校正后，研究基线时频繁疼痛的膝关节与无疼痛的膝关节相比，软骨丢失率是否存在差异。
对骨关节炎倡议项目的718名参与者的一侧膝关节进行检查：310例计算得出的Kellgren/Lawrence（K/L）分级为2级，299例计算得出的K/L分级为3级，109例计算得出的K/L分级为4级。通过磁共振成像评估（亚区域）软骨厚度的12个月变化。选择负重内侧股骨髁中央亚区域的软骨厚度变化和有序值1（OV1）作为主要终点。频繁的膝关节症状定义为在前一年至少1个月的大多数日子里出现疼痛、酸痛或僵硬。
内侧股骨髁中央亚区域软骨厚度的平均12个月变化率在无疼痛的膝关节中为-12μm（标准化反应均值[SRM]-0.15）（n = 146），在偶尔疼痛的膝关节中为-27μm（SRM -0.25）（n = 255），在频繁疼痛的膝关节中为-54μm（SRM -0.32）（n = 317）。在对年龄、性别、体重指数和计算得出的K/L分级进行校正后，频繁疼痛的膝关节与无疼痛的膝关节之间的变化率存在显著差异（P = 0.011，R² = 2.6%，频繁疼痛的偏R² = 1.4%）。在计算得出的K/L分级为2级/计算得出的K/L分级为3级的膝关节分层样本中，以及在仅限于基线和随访期间疼痛频率一致的膝关节的分析中，发现了类似结果。OV1结果显示出类似趋势，但不显著。
无论是否对影像学疾病分期进行校正或分层，频繁疼痛的膝关节纵向内侧软骨丢失率均高于无疼痛的膝关节。在临床试验中纳入频繁膝关节疼痛的参与者可提高观察到的结构进展率（即软骨丢失）和对变化的敏感性。
