Department of Physiotherapy, Singapore General Hospital, Singapore; Medicine Academic Programme, Duke-NUS Graduate Medical School, Singapore.
Department of Orthopaedic Surgery, Woodlands Health Campus, National Healthcare Group, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
J Arthroplasty. 2023 Sep;38(9):1705-1713.e1. doi: 10.1016/j.arth.2023.03.044. Epub 2023 Mar 20.
Although self-reported measures of physical disability are strong indication criterion for total knee arthroplasty (TKA) in painful knee osteoarthritis (OA), some patients may report greater-than-observed disability. Contributing factors to this discordance are relatively unexplored. We aimed to examine whether pain and negative affect, including anxiety and depression, were associated with the discordance of self-reported measures with performance-based measures (PPM) of physical function.
We used cross-sectional data (n = 212) from two randomized rehabilitation trials in knee OA. All patients were assessed for knee pain intensity and symptoms of anxiety and depression. Self-reported function was assessed by the Western Ontario and McMaster Universities Arthritis Index (WOMAC) physical-function subscale. Objective performance-based measures (PPMs) of physical function were assessed by timed gait and stair tests. Continuous discordance scores were quantified by the difference in percentiles between WOMAC and PPMs (WOMAC-PPM), where a positive discordance, WOMAC-PPM >0, implied greater perceived than observed disability.
Around 1 in 4 patients had >20 percentile units in WOMAC-PPM discordance. In Bayesian regression analyses, knee pain intensity had >99% posterior probability of positive associations with WOMAC-PPM discordance. Among patients awaiting TKA, anxiety intensity had approximately 99% probability of positive associations with discordance, and these associations had >65% probability of exceeding 10 percentile units. In contrast, depression had low (79% to 88%) probability of any association with discordance.
In patients who have knee OA, a sizable proportion reported substantially greater physical disability than actually observed. Pain and anxiety intensity, but not depression, were meaningful predictors of this discordance. If validated, our findings may help in refining patient selection criteria for TKA.
尽管自我报告的身体残疾程度是膝关节置换术（TKA）治疗疼痛性膝关节骨关节炎（OA）的有力指标，但一些患者可能会报告比实际观察到的更大的残疾程度。造成这种差异的因素尚未得到充分探讨。我们旨在研究疼痛和负性情绪（包括焦虑和抑郁）是否与自我报告的身体功能测量结果与基于表现的测量（PPM）之间的差异有关。
我们使用了两项膝关节骨关节炎随机康复试验的横断面数据（n=212）。所有患者均评估了膝关节疼痛强度和焦虑及抑郁症状。自我报告的功能通过西安大略和麦克马斯特大学骨关节炎指数（WOMAC）的身体功能子量表进行评估。客观的基于表现的测量（PPM）通过计时步行和楼梯测试进行评估。通过 WOMAC 与 PPM 之间的百分位数差异量化连续的不匹配得分（WOMAC-PPM），其中，WOMAC-PPM＞0 表示感知到的残疾程度大于实际观察到的残疾程度。
大约有 1/4 的患者在 WOMAC-PPM 不匹配中存在＞20 个百分位单位的差异。在贝叶斯回归分析中，膝关节疼痛强度与 WOMAC-PPM 不匹配有＞99%的后验概率存在正相关。在等待 TKA 的患者中，焦虑强度与不匹配有大约 99%的正相关概率，并且这些关联有＞65%的概率超过 10 个百分位单位。相比之下，抑郁与不匹配的关联可能性较低（79%至 88%）。
在患有膝关节骨关节炎的患者中，相当一部分患者报告的身体残疾程度明显大于实际观察到的残疾程度。疼痛和焦虑强度是这种差异的有意义的预测指标，而抑郁不是。如果得到验证，我们的发现可能有助于完善 TKA 的患者选择标准。
