Evaluation of clinical and radiographic measures and reliability of the quadriceps angle measurement in elderly women with knee osteoarthritis

Introduction Knees osteoarthritis (OA) is a complex degenerative disease with intra-articular changes affecting the amplitude of the quadriceps angle (Q). To measure this variable, it is necessary to use reliable protocols aiming at methodological reproducibility. The objective was to evaluate the intra-examiner and inter-examiner reliability of clinical and radiographic measures of the Q angle and to investigate the relationship between the degree of OA and the magnitude of this angle in the elderly. Materials and methods 23 volunteers had the Q angle measured by two evaluators at 48-h interval. Clinical measurements were collected by using the universal goniometer in the same position adopted in the radiographic examination. Results The intra-examiner reliability was good (0.722 to 0.763) for radiographic measurements and low (0.518 to 0.574) for clinical assessment, while inter-examiner reliability was moderate (0.634) for radiographic measurements and low (0.499) to the clinics. The correlation analysis between the radiographic values with the OA classification showed no correlation between them (p = 0.824 and r = -0.024). Conclusion Clinically, it is suggested that the radiographic examination is preferable to evaluate the Q angle of elderly women with knee osteoarthritis. Moreover, the magnitude of this angle did not correlate with the degree of impairment of OA in this population.

引言 膝关节骨关节炎（knee osteoarthritis, OA）是一种复杂的退行性疾病，其关节内改变会影响股四头肌角（quadriceps angle, Q角）的幅度。为精准测量该变量，需采用具备方法学可重复性的可靠方案。本研究旨在评估股四头肌角临床与影像学测量的检查者内及检查者间信度，并探讨老年人群中骨关节炎严重程度与该角幅度之间的关联。

材料与方法 招募23名志愿者，由两名评估者间隔48小时分别测量其股四头肌角。临床测量采用通用量角器（universal goniometer），测量体位与影像学检查时保持一致。

结果 影像学测量的检查者内信度良好（0.722~0.763），临床评估的检查者内信度较低（0.518~0.574）；影像学测量的检查者间信度为中等（0.634），临床测量的检查者间信度较低（0.499）。影像学测量值与骨关节炎分级的相关性分析显示二者无显著关联（p=0.824，r=-0.024）。

结论 临床层面而言，评估老年女性膝关节骨关节炎患者的股四头肌角时，影像学检查更具优势。此外，该研究人群中，股四头肌角的幅度与骨关节炎的损伤程度并无相关性。