A pull function attachment to manual wheelchairs: a case report on usability and shoulder pain in people with spinal cord injury

INTRODUCTION: Shoulder pain mostly due to high biomechanical load of the anterior-shoulder musculature is prevalent among manual wheelchair users with spinal cord injury or disorder (SCI/D). This case study showcases a novel pull-function attachment to the wheelchair that reverses the propulsion motion by pulling rather than pushing the wheelchair. Additionally, the study reports its preliminary usability and impact on shoulder pain.

CASE PRESENTATION: Four individuals with SCI/D (median age: 33; 1 female) used the novel pull-function attachment to the manual wheelchair for six weeks. Usability (System Usability Scale; ranging from 1 = 'strongly disagree' to 5 = 'strongly agree') and daily usage time were assessed. Shoulder pain intensity was explored before and after the six weeks using the Wheelchair User's Shoulder Pain Index. Median usability scores were ≥3.0 for 5/6 items, indicating high usability of the assistive technology. Shoulder pain intensity was reduced in all participants at the post-test (median change: -6.3), with the change in shoulder pain exceeding the minimal detectable change for 2/3 participants.

DISCUSSION: The results of this case study suggest high usability of the pull-function attachment to the wheelchair. The decreases in shoulder pain intensity reported following six weeks of use were noticeable and may have clinical relevance. This novel assistive technology that enables forward propulsion by pulling rather than pushing the wheelchair may therefore have the potential to reduce shoulder pain in manual wheelchair users with SCI/D.