Laboratory of Kinesiology Willy Taillard, Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
IFSTTAR, LBMC UMR_T9406, LBMC, Univ Lyon, Université Claude Bernard Lyon 1, Lyon, France.
PLoS One. 2020 Apr 24;15(4):e0232064. doi: 10.1371/journal.pone.0232064. eCollection 2020.
Clinical gait analysis is widely used in clinical routine to assess the function of patients with motor disorders. The proper assessment of the patient's function relies greatly on the repeatability between the measurements. Marker misplacement has been reported as the largest source of variability between measurements and its impact on kinematics is not fully understood. Thus, the purpose of this study was: 1) to evaluate the impact of the misplacement of the lateral femoral epicondyle marker on lower limb kinematics, and 2) evaluate if such impact can be predicted. The kinematic data of 10 children with cerebral palsy and 10 aged-match typical developing children were included. The lateral femoral epicondyle marker was virtually misplaced around its measured position at different magnitudes and directions. The outcome to represent the impact of each marker misplacement on the lower limb was the root mean square deviations between the resultant kinematics from each simulated misplacement and the originally calculated kinematics. Correlation and regression equations were estimated between the root mean square deviation and the magnitude of the misplacement expressed in percentage of leg length. Results indicated that the lower-limb kinematics is highly sensitive to the lateral femoral epicondyle marker misplacement in the anterior-posterior direction. The joint angles most impacted by the anterior-posterior misplacement were the hip internal-external rotation (5.3° per 10 mm), the ankle internal-external rotation (4.4° per 10 mm) and the knee flexion-extension (4.2° per 10 mm). Finally, it was observed that the lower the leg length, the higher the impact of misplacement on kinematics. This impact was predicted by regression equations using the magnitude of misplacement expressed in percentage of leg length. An error below 5° on all joints requires a marker placement repeatability under 1.2% of the leg length. In conclusion, the placement of the lateral femoral epicondyle marker in the antero-posterior direction plays a crucial role on the reliability of gait measurements with the Conventional Gait Model.
临床步态分析广泛应用于临床常规中，以评估运动障碍患者的功能。患者功能的适当评估在很大程度上依赖于测量之间的可重复性。已报道标记物错位是测量值之间变异性的最大来源，但其对运动学的影响尚未完全了解。因此，本研究的目的是：1）评估外侧股骨髁标记物错位对下肢运动学的影响，以及 2）评估这种影响是否可以预测。本研究纳入了 10 名脑瘫儿童和 10 名年龄匹配的典型发育儿童的运动学数据。在不同幅度和方向上，虚拟地将外侧股骨髁标记物放置在其测量位置的周围。代表每次标记物错位对下肢影响的结果是，从每次模拟错位和原始计算运动学得出的运动学结果之间的均方根偏差。在腿长百分比表示的错位幅度和均方根偏差之间估计了相关和回归方程。结果表明，下肢运动学对前-后方向上的外侧股骨髁标记物错位非常敏感。前-后错位对髋关节内外旋转（每 10mm 5.3°）、踝关节内外旋转（每 10mm 4.4°）和膝关节屈伸（每 10mm 4.2°）影响最大。最后，观察到腿长越低，错位对运动学的影响越大。使用腿长百分比表示的错位幅度的回归方程可以预测这种影响。所有关节的误差低于 5°，则需要标记物放置的重复性低于腿长的 1.2%。总之，在传统步态模型中，外侧股骨髁标记物在前后方向上的放置对步态测量的可靠性起着至关重要的作用。
