Chapman Ryan M, Taylor Kelly B, Kaczynski Emily, Khodabakhsh Shayan, Richards Skye, Hutchinson Jayson B, Marchand Robert C
University of Rhode Island, Department of Kinesiology, 25 West Independence Way, Kingston, RI 02881, USA; University of Rhode Island, Department of Electrical, Computer, and Biomedical Engineering, 4 East Alumni Avenue, Kingston, RI 02881, USA.
Ortho Rhode Island, 70 Kenyon Avenue, Wakefield, RI 02879, USA.
Knee. 2025 Jun;54:316-328. doi: 10.1016/j.knee.2025.03.001. Epub 2025 Apr 1.
Commercially available wearable sensors monitoring knee range of motion (ROM) are gaining traction in orthopaedics, but few studies validate against optical motion capture (MOCAP) in total knee arthroplasty (TKA) patients. Furthermore, wearable calibration is essential for accurate measurements, yet few investigations evaluate calibration and ROM accuracy. This study assessed one commercial wearable sensor system's calibration (goniometric versus MOCAP) and sagittal knee angle computation accuracy in TKA patients during activities.
Twenty TKA patients were recruited (5 lost to follow-up). Following a sensor tutorial (MotionSense, Stryker, Mahwah, NJ), participants self-applied sensors for pre-TKA data capture. TKA was then performed by one surgeon followed by identical post-TKA data captures. MOCAP and wearable sensor data were collected during activities. MOCAP sagittal knee angles (θ) were compared to two wearable sensor knee angles: 1) θ = goniometric calibration, 2) θ = MOCAP calibration. Two-way ANOVAs evaluated the impact of time (pre-TKA vs. post-TKA) and calibration type (goniometry vs. MOCAP) on calibration angles and wearable sensor error. Variance equality tests compared pre-TKA vs. post-TKA and goniometric vs. MOCAP calibration.
No significant differences were noted pre-TKA vs. post-TKA. Calibration angles differed significantly with goniometry yielding significantly more error than MOCAP. MOCAP calibration reduced error below clinically acceptable levels (<5°) during activities and with significantly less error variance.
MOCAP calibration significant improved accuracy of knee angle computations to acceptable levels (<5°). Accordingly, these wearables are suitable for continuous knee ROM monitoring after calibrating with correct angles, Future studies should investigate specific activities and sensor misplacement on angle measurements.
市面上用于监测膝关节活动范围（ROM）的可穿戴传感器在骨科领域越来越受到关注，但很少有研究在全膝关节置换术（TKA）患者中与光学运动捕捉（MOCAP）进行对比验证。此外，可穿戴设备的校准对于准确测量至关重要，但很少有研究评估校准和ROM准确性。本研究评估了一种商用可穿戴传感器系统在TKA患者活动期间的校准（测角法与MOCAP）以及矢状面膝关节角度计算的准确性。
招募了20名TKA患者（5名失访）。在进行传感器使用指导（MotionSense，史赛克公司，新泽西州马哈瓦）后，参与者自行佩戴传感器进行TKA术前数据采集。然后由一名外科医生进行TKA手术，随后进行相同的TKA术后数据采集。在活动期间收集MOCAP和可穿戴传感器数据。将MOCAP矢状面膝关节角度（θ）与两个可穿戴传感器膝关节角度进行比较：1）θ = 测角法校准，2）θ = MOCAP校准。双向方差分析评估时间（TKA术前与术后）和校准类型（测角法与MOCAP）对校准角度和可穿戴传感器误差的影响。方差齐性检验比较TKA术前与术后以及测角法与MOCAP校准。
TKA术前与术后未发现显著差异。校准角度存在显著差异，测角法产生的误差明显大于MOCAP。MOCAP校准在活动期间将误差降低到临床可接受水平（<5°），且误差方差显著更小。
MOCAP校准显著提高了膝关节角度计算的准确性至可接受水平（<5°）。因此，这些可穿戴设备在用正确角度校准后适用于连续膝关节ROM监测。未来的研究应调查特定活动以及传感器放置不当对角度测量的影响。
