The accuracy of measuring glenohumeral motion with a surface humeral cuff

Abstract

Conclusions about normal and pathologic shoulder motion are frequently made from studies using skin surface markers, yet accuracy of such sensors representing humeral motion is not well known. Nineteen subjects were investigated with flock of birds electromagnetic sensors attached to transcortical pins placed into the scapula and humerus, and a thermoplastic cuff secured on the arm. Subjects completed two repetitions of raising and lowering the arm in the sagittal, scapular and coronal planes, as well as shoulder internal and external rotation with the elbow at the side and abducted to ninety degrees. Humeral motion was recorded simultaneously from surface and bone fixed sensors. The average magnitude of error was calculated for the surface and bone fixed measurements throughout the range of motion. ANOVA tested for differences across angles of elevation, raising and lowering, and differences in body mass index. For all five motions tested, the plane of elevation rotation average absolute error ranged from 0-2°, while the humeral elevation rotation average error ranged from 0-4°. The axial rotation average absolute error was much greater, ranging from 5° during elevation motions to approaching 30° at maximum excursion of internal/external rotation motions. Average absolute error was greater in subjects with body mass index greater than 25. Surface sensors are an accurate way of measuring humeral elevation rotations and plane of elevation rotations. Conversely, there is a large amount of average error for axial rotations when using a humeral cuff to measure glenohumeral internal/external rotation as the primary motion.

Relationship Between Skin Intrinsic Fluorescence—an Indicator of Advanced Glycation End Products—and Upper Extremity Impairments in Individuals With Diabetes Mellitus

“…In addition, participants with BMI over 35 kg/m 2 were excluded as the kinematic measurement errors are known to be large in people with high BMI. 33 Control participants were phone screened for shoulder pain because we wanted the group with DM to be compared to a control group without any shoulder impairments.…”

“…Using the same methods, the difference between the surface marker versus a bone pin marker for humerus motion was 0-4º for elevation angle and 1.7-2.3º for axial rotation movements. 33 The angles extracted for this study were the peak humerothoracic elevation and peak glenohumeral external rotation.…”

Measurement and Description of Three-Dimensional Shoulder Range of Motion With Degrees of Freedom Interactions

“…Lower arm was added to correct soft tissue artifacts affecting arm axial rotation [11], Then, the model was calibrated to the participants using six setup trials for functionally locating shoulder centers and elbow axes of rotation [21,22]. Joints angletime-histories were estimated using inverse kinematics [23] from the recorded marker trajectories.…”

“…According to the American Academy of Orthopaedic Sur geons, electromagnetic tracking system gave the "best available data for anatomic shoulder RoM" of normal shoulder motion [9], However, electromagnetic systems are limited for elevation angles higher than 120 deg [10] and arm axial rotation [11], Opti cal measurement is expected to increase the angular accuracy. Specifically, a redundant marker set coupled with least square optimization algorithm and kinematic chain model has shown to reduce skin movement artifacts [12].…”

The role of scapular kinematics in patients with different shoulder musculoskeletal disorders: A systematic review approach

“…Furthermore, these comparisons were provided using surface electromagnetic sensors. However, skin-motion artifacts related to surface electromagnetic sensors may create the differences among the groups (Hamming, Braman, Phadke, LaPrade, & Ludewig, 2012;Karduna, McClure, Michener, & Sennett, 2001).…”