Comparison of Strain-Gage and Fiber-Optic Goniometry for Measuring Knee Kinematics During Activities of Daily Living and Exercise

Abstract

There is increasing interest in wearable sensor technology as a tool for rehabilitation applications in community or home environments. Recent studies have focused on evaluating inertial based sensing (accelerometers, gyroscopes, etc.) that provide only indirect measures of joint motion. Measurement of joint kinematics using flexible goniometry is more direct, and still popular in laboratory environments, but has received little attention as a potential tool for wearable systems. The aim of this study was to compare two goniometric devices: a traditional strain-gauge flexible goniometer, and a fiberoptic flexible goniometer, for measuring dynamic knee flexion/extension angles during activity of daily living: chair rise, and gait; and exercise: deep knee bends, against joint angles computed from a "gold standard" Vicon motion tracking system. Six young adults were recruited to perform the above activities in the lab while wearing a goniometer on each knee, and reflective markers for motion tracking. Kinematic data were collected simultaneously from the goniometers (one on each leg) and the motion tracking system (both legs). The results indicate that both goniometers were within 2-5 degrees of the Vicon angles for gait and chair rise. For some deep knee bend trials, disagreement with Vicon angles exceeded ten degrees for both devices. We conclude that both goniometers can record ADL knee movement faithfully and accurately, but should be carefully considered when high (>120 deg) knee flexion angles are required.

Accurate Prediction of Knee Angles during Open-Chain Rehabilitation Exercises Using a Wearable Array of Nanocomposite Stretch Sensors

“…The magnitude of these effects was not found to affect the accuracy of the current analysis, and additional work characterizing these important sensor properties is currently underway. The impact of these errors is similar to previous IMUs [ 61 , 62 , 63 , 64 , 65 ] and high deflection strain gauges [ 54 , 66 , 67 ] used to measure joint angles. By including the derivatives of the sensor outputs in the model, the average improvement of the RMSE in the flexion/extension and internal/external rotation degrees of freedom were −16.9% and −9.3%, respectively.…”

Biomechanical Study of a Tricompartmental Unloader Brace for Patellofemoral or Multicompartment Knee Osteoarthritis

“…This resulted in a sample of eight participants (age 25 ± 5 years, mass 66 ± 12 kg, height 164 ± 8 cm, six females). The DKB test protocol is detailed elsewhere (Mohamed et al, 2012). Briefly, participants stood with each foot on side-by-side force plates and completed the DKB task three times.…”

A Lightweight Exoskeleton-Based Portable Gait Data Collection System

“…By aligning the rotation axis of the goniometer with the corresponding biological joint, the sensor output directly reflects the joint displacement (i.e., no complex data processing needed). The most commonly used type of goniometer is the traditional rotary potentiometer, and magnetic encoders and fiber-optical sensors can also serve as the goniometers for joint measurement purposes [14][15][16]. Note that, when portable goniometers are used, these devices can be used for mobile gait measurement without being limited to the lab environments, facilitating the gait data collection in people's real-world daily-living scenarios.…”