Tsamassiotis Spiros, Schwarze Michael, Gehring Philipp, Karkosch Roman F, Tücking Lars-René, Einfeldt Ann-Kathrin, Jakubowitz Eike
Department of Orthopaedic Surgery Hannover Medical School, Diakovere Annastift Hannover Germany.
Department of Orthopaedic Surgery Hannover Medical School, Laboratory for Biomechanics and Biomaterials Hannover Germany.
J Exp Orthop. 2025 Jan 3;12(1):e70134. doi: 10.1002/jeo2.70134. eCollection 2025 Jan.
Effective rehabilitation after orthopaedic surgery is critical. The early post-operative phase is increasingly managed in outpatient settings, necessitating objective measures such as step counts to monitor rehabilitation progress. However, it remains unclear if commercially available wearables or accelerometers using simple algorithms can accurately count steps in early post-operative conditions. We hypothesised that only accelerometers could accurately determine the number of steps under these conditions.
This case series involved 20 healthy subjects, 7 female and 13 males, walking in a circle at varying speeds under partial loading with three different walking aids (forearm crutches, walking frame and rolling walker) and four wearables (Vivofit 4, Fenix 3HR, Fitbit Charge 3 and Omron HJ-325) and one accelerometer (AX6) worn on the wrist, hip and ankle. The two-point and modified three-point gait patterns commonly used post-operatively were simulated. The primary end point was the relative error (RE), defined as RE = (manual count - automated count)/manual count, of each wearable measurement compared to visual and video step counting, the gold standard.
The RE of AX6 and Fitbit was less than 0.1 for all walking aids except the rolling walker, with AX6 showing the lowest standard deviation (SD) compared to other wearables. Other wearables had significantly higher RE. Increased gait speed generally improved accuracy, reducing RE in most devices, except for the AX6, which showed the opposite trend. At 0.6 m/s, only AX6 achieved an RE below 0.1. The ankle was identified as the best measuring location.
During the early post-operative period, commercial wearables can only accurately count steps under specific conditions and should be used cautiously for monitoring steps in the early post-operative phase. However, accelerometers with appropriate coding appear suitable for this purpose.
Level III diagnostic study.
骨科手术后有效的康复治疗至关重要。术后早期阶段越来越多地在门诊环境中进行管理，因此需要诸如步数计数等客观指标来监测康复进展。然而，尚不清楚市售的可穿戴设备或使用简单算法的加速度计能否在术后早期准确计数步数。我们假设在这些条件下只有加速度计能够准确确定步数。
本病例系列研究纳入了20名健康受试者，其中7名女性和13名男性，他们在部分负重情况下使用三种不同的助行器（前臂拐杖、步行架和滚动助行器），并佩戴四种可穿戴设备（Vivofit 4、Fenix 3HR、Fitbit Charge 3和欧姆龙HJ-325）以及一个佩戴在手腕、髋部和脚踝处的加速度计（AX6），以不同速度绕圈行走。模拟了术后常用的两点和改良三点步态模式。主要终点是与视觉和视频步数计数（金标准）相比，每个可穿戴设备测量的相对误差（RE），定义为RE =（手动计数 - 自动计数）/手动计数。
除滚动助行器外，AX6和Fitbit在所有助行器上的RE均小于0.1，与其他可穿戴设备相比，AX6的标准差（SD）最低。其他可穿戴设备的RE明显更高。步态速度增加通常会提高准确性，大多数设备的RE降低，但AX6除外，其显示出相反的趋势。在0.6 m/s时，只有AX6的RE低于0.1。脚踝被确定为最佳测量位置。
在术后早期，市售可穿戴设备仅在特定条件下能准确计数步数，在术后早期用于监测步数时应谨慎使用。然而，具有适当编码的加速度计似乎适用于此目的。
III级诊断研究。
