Takahashi T, Yamanaka N, Komatsu M, Ogawa Y, Yoshida S, Yamamoto H
Department of Orthopaedics, Kochi Medical School, Oko-cho, Nankoku, Kochi, 783-8505, Japan.
Osteoarthritis Cartilage. 2004 Mar;12(3):256-9. doi: 10.1016/j.joca.2003.10.005.
The purpose of this study was to evaluate the inter- and intraobserver variability in measuring the tibio-femoral angle using our new computer-assisted method, and to compare it with a conventional manual method.
Radiography of all patients of osteoarthritis of the knee in outpatient were performed with standing on both legs, and with conventional antero-posterior weight bearing view of the knee fully extended. Three examiners measured the tibio-femoral angle with the computerized method in 52 subjects with osteoarthritis (73 knees). The tibio-femoral angle was measured using a computer-assisted method in which the observer must visually determine and select eight points on the margins of the femur and tibia on a radiographic image displayed on a computer monitor. The inter- and intraobserver Intra-class correlation (ICC) was analyzed.
The interobserver mean correlation of computer-assisted method was 0.970 with a mean difference of 0.38 degrees (S.D. 1.125 degrees). The intraobserver mean ICC of computer-assisted method was 0.973, with a mean difference of 0.16 degrees (S.D. 1.12 degrees). An analysis of the difference between conventional methods and our new system showed a mean ICC of 0.922, with an intersystem mean difference of 0.295 degrees (S.D. 1.82 degrees).
Our computer-assisted method of measuring the tibio-femoral angle was simple, easy, and quick, and should be considered as an alternate method for measurement.
本研究旨在评估使用我们新的计算机辅助方法测量胫股角时观察者间和观察者内的变异性，并将其与传统手动方法进行比较。
对门诊所有膝骨关节炎患者进行双腿站立位、膝关节完全伸直的常规前后位负重X线摄影。三名检查者采用计算机化方法对52例骨关节炎患者（73个膝关节）测量胫股角。采用计算机辅助方法测量胫股角，观察者必须在计算机显示器上显示的X线图像上目视确定并选择股骨和胫骨边缘的八个点。分析观察者间和观察者内的组内相关系数（ICC）。
计算机辅助方法的观察者间平均相关系数为0.970，平均差异为0.38度（标准差1.125度）。计算机辅助方法的观察者内平均ICC为0.973，平均差异为0.16度（标准差1.12度）。对传统方法与我们新系统之间差异的分析显示，平均ICC为0.922，系统间平均差异为0.295度（标准差1.82度）。
我们的计算机辅助测量胫股角的方法简单、易行、快速，应被视为一种替代测量方法。
