Exercise is universally recommended as a primary strategy for the management of knee osteoarthritis (OA) pain. The recommendations are based on results from more than 100 randomized controlled trials (RCTs) that compare exercise to no-attention control groups. However, due to the inherent difficulties with adequate placebo control, participant blinding and the use of patient-reported outcomes, the existing RCT evidence is imperfect. To better understand the evidence used to support a causal relationship between exercise and knee OA pain relief, we examined the existing evidence through the Bradford Hill considerations for causation. The Bradford Hill considerations, first proposed in 1965 by Sir Austin Bradford Hill, provide a framework for assessment of possible causal relationships. There are 9 considerations by which the evidence is reviewed: Strength of association, Consistency, Specificity, Temporality, Biological Gradient (Dose-Response), Plausibility, Coherence, Experiment, and Analogy. Viewing the evidence from these 9 viewpoints did neither bring forward indisputable evidence for nor against the causal relationship between exercise and improved knee OA pain. Rather, we conclude that the current evidence is not sufficient to support claims about (lack of) causality. With our review, we hope to advance the continued global conversation about how to improve the evidence-based management of patients with knee OA.

中文翻译：

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运动治疗膝骨关节炎疼痛：关联还是因果关系？


运动被普遍推荐作为治疗膝骨关节炎 (OA) 疼痛的主要策略。这些建议基于 100 多项随机对照试验 (RCT) 的结果，这些试验将运动组与不注意对照组进行比较。然而，由于充分的安慰剂对照、参与者盲法以及使用患者报告的结果等固有的困难，现有的随机对照试验证据并不完善。为了更好地理解支持运动与膝骨关节炎疼痛缓解之间因果关系的证据，我们通过 Bradford Hill 因果关系考虑因素检查了现有证据。 Bradford Hill 考虑因素由 Austin Bradford Hill 爵士于 1965 年首次提出，为评估可能的因果关系提供了一个框架。审查证据时需要考虑 9 个因素：关联强度、一致性、特异性、时间性、生物梯度（剂量-反应）、合理性、连贯性、实验和类比。从这 9 个观点来看，既没有提出无可争议的证据来支持也没有反对运动与改善膝骨关节炎疼痛之间的因果关系。相反，我们的结论是，当前的证据不足以支持关于（缺乏）因果关系的主张。通过我们的审查，我们希望推动关于如何改善膝关节骨关节炎患者循证治疗的持续全球对话。