Humeral elevation workspace during daily life of adults with spinal cord injury who use a manual wheelchair compared to age and sex matched able-bodied controls

Abstract

Shoulder pain and pathology are extremely common for individuals with spinal cord injuries (SCI) who use manual wheelchairs (MWC). Although risky humeral kinematics have been measured during wheelchair-based activities performed in the lab, little is known about arm motion in the free-living environment. The purpose of this study was to measure the humeral elevation workspace throughout a typical day for individuals with SCI and able-bodied matched controls. Thirty-four individuals with SCI who use a MWC (42.7 +/- 12.7 years of age, 28 males/6 females, C6-L1) and 34 age-and sex-matched controls were enrolled. Participants wore three inertial measurement units (IMU) on their upper arms and torso for one to two days. Humeral elevation angles were estimated and the percentage of time individuals spent in five elevation bins (0-30 degrees, 30-60 degrees, 60-90 degrees, 90-120 degrees, and 120-180 degrees) were calculated. For both arms, the SCI cohort spent a significantly lower percentage of the day in 0-30 degrees of humeral elevation (Dominant: SCI= 15.7 +/- 12.6%, Control= 32.1 +/- 15.6%, p<0.0001; Non-Dominant: SCI= 21.9 +/- 17.8%, Control= 34.3 +/- 15.5%, p=0.001) and a significantly higher percentage of time in elevations associated with tendon compression (30-60 degrees of humeral elevation, Dominant: SCI= 62.8 +/- 14.4%, Control= 49.9.1 +/- 13.0%, p<0.0001; Non-Dominant: SCI= 58.8 +/- 14.9%, Control= 48.3 +/- 13.6%, p=0.003) than controls. The increased percentage of time individuals with SCI spent in elevations associated with tendon compression may contribute to increased shoulder pathology. Characterizing the humeral elevation workspace utilized throughout a typical day may help in understanding the increased prevalence of shoulder pain and pathology in individuals with SCI who use MWCs.

Duration of Static and Dynamic Periods of the Upper Arm During Daily Life of Manual Wheelchair Users and Matched Able-Bodied Participants: A Preliminary Report

“…Participants were asked to wear the sensors for two typical days for at least 8 h, excluding bathing and swimming, and take them off before going to bed. Participants were also asked to charge the sensors overnight (between data collections) and perform a functional calibration at the beginning of each day and after re-donning the sensors if they were taken off in the middle of the day (Goodwin et al, 2020 ). Both cohorts were instructed to perform their regular daily routines; the control cohort did not use MWCs.…”

“…Custom MATLAB (Mathworks, Natick, Massachusetts) code was written to calculate the humeral elevation and static vs. dynamic status of each second of the day. This process is described in detail elsewhere (Goodwin et al, 2020 , 2021 ). In short, the signal magnitude area (SMA) of the raw acceleration data was calculated for each second and used to determine if each arm was static or dynamic.…”

“…The humeral elevation angles were calculated using the functional calibration to align the inertial reference frame with the anatomical axes. Humeral elevation and thorax deviation angles were defined as the angle between the long axis of the body segment (defined from the function calibration) and vertical; these angles are only dependent on the estimated direction of gravity relative to the body segment and, therefore, are drift-free metrics for quantifying body segment motions (Goodwin et al, 2020 ). The humeral elevation angles have previously been validated in unpublished data where five individuals with SCI performed 10 reaching tasks.…”

“…Each second of the data was classified as static or dynamic in one of the humeral elevation ranges (0–30°, 30–60°, 60–90°, 90–120°, and >120°). The humeral elevation angle was calculated with respect to the neutral humerus position and not with respect to the thorax; therefore, we eliminated data when the average torso angle was over 30° (Goodwin et al, 2020 ). By eliminating data where the trunk was at high deviation angles from upright, periods where the humeral elevation angle was likely much different than the humerothoracic angle were not included in the analysis.…”

“…Our group's investigation into the link of arm use and shoulder pain and pathology has focused on differentiating arm use patterns during daily life between MWC users and matched controls with the goal of explaining the striking difference in shoulder pain and pathology between groups. We have previously used IMUs in the free-living environment to capture the humeral elevation workspace during typical days for these two cohorts (Goodwin et al, 2020 ), and we have investigated the use of a threshold to decipher static from dynamic arm use during daily life (Goodwin et al, 2021 ). The motivation for this line of investigation is evidence-based knowledge that factors that affect overall health and damage to the rotator cuff tendons are multifactorial, ultimately resulting from different types of motion and loading patterns (Lewis, 2010 ; McCreesh and Lewis, 2013 ).…”