Academic Rheumatology, Clinical Sciences Building, City Hospital, Nottingham NG5 1PB, UK.
BMC Med Res Methodol. 2010 Jun 18;10:57. doi: 10.1186/1471-2288-10-57.
For large scale epidemiological studies clinical assessments and radiographs can be impractical and expensive to apply to more than just a sample of the population examined. The study objectives were to develop and validate two novel instruments for self-reported knee malalignment and foot rotation suitable for use in questionnaire studies of knee pain and osteoarthritis.
Two sets of line drawings were developed using similar methodology. Each instrument consisted of an explanatory question followed by a set of drawings showing straight alignment, then two each at 7.5 degrees angulation and 15 degrees angulation in the varus/valgus (knee) and inward/outward (foot) directions. Forty one participants undertaking a community study completed the instruments on two occasions. Participants were assessed once by a blinded expert clinical observer with demonstrated excellent reproducibility. Validity was assessed by sensitivity, specificity and likelihood ratio (LR) using the observer as the reference standard. Reliability was assessed using weighted kappa (kappa). Knee malalignment was measured on 400 knee radiographs. General linear model was used to assess for the presence of a linear increase in knee alignment angle (measured medially) from self-reported severe varus to mild varus, straight, mild valgus and severe valgus deformity.
Observer reproducibility (kappa) was 0.89 and 0.81 for the knee malalignment and foot rotation instruments respectively. Self-reported participant reproducibility was also good for the knee (kappa 0.73) and foot (kappa 0.87) instruments. Validity was excellent for the knee malalignment instrument, with a sensitivity of 0.74 (95%CI 0.54, 0.93) and specificity of 0.97 (95%CI 0.94, 1.00). Similarly the foot rotation instrument was also found to have high sensitivity (0.92, 95%CI 0.83, 1.01) and specificity (0.96, 95%CI 0.93, 1.00). The knee alignment angle increased progressively from self reported severe varus to mild varus, straight, mild valgus and severe valgus knee malalignment (ptrend <0.001).
The two novel instruments appear to provide a valid and reliable assessment of self-reported knee malalignment and foot rotation, and may have a practical use in epidemiological studies.
对于大规模的流行病学研究，对除了样本之外的人群进行临床评估和 X 光检查既不实际也不经济。本研究的目的是开发和验证两种适用于膝关节疼痛和骨关节炎问卷研究的新型膝关节对线不良和足部旋转的自我报告工具。
使用类似的方法开发了两组线条图。每个工具都由一个解释性问题组成，后面跟着一组显示直线对齐的图片，然后分别是 7.5 度和 15 度内翻/外翻（膝关节）和内翻/外翻（足部）方向的各两张图片。41 名参加社区研究的参与者在两次不同时间完成了这些工具。参与者由一位经过验证的具有良好可重复性的盲法临床观察专家进行了一次评估。使用观察者作为参考标准，通过敏感性、特异性和似然比（LR）来评估有效性。使用加权 kappa（kappa）评估可靠性。对 400 张膝关节 X 光片进行了膝关节对线测量。使用一般线性模型评估自报严重内翻至轻度内翻、直线、轻度外翻和严重外翻畸形时膝关节对线角度（内侧测量）的线性增加。
观察者的可重复性（kappa）分别为膝关节对线不良和足部旋转工具的 0.89 和 0.81。自我报告的参与者可重复性也很好，膝关节（kappa 0.73）和足部（kappa 0.87）工具。膝关节对线不良工具的有效性非常好，灵敏度为 0.74（95%CI 0.54, 0.93），特异性为 0.97（95%CI 0.94, 1.00）。同样，足部旋转工具也具有很高的灵敏度（0.92, 95%CI 0.83, 1.01）和特异性（0.96, 95%CI 0.93, 1.00）。自报严重内翻至轻度内翻、直线、轻度外翻和严重外翻膝关节对线不良时，膝关节对线角度逐渐增加（ptrend<0.001）。
这两种新型工具似乎提供了一种有效且可靠的自我报告膝关节对线不良和足部旋转的评估方法，并且可能在流行病学研究中具有实际用途。
