Natural History of Shoulder Pathology in Wheelchair Users

PROJECT SUMMARY/ABSTRACT This competitive renewal 1) expands on a prospective longitudinal study that defines the natural history of shoulder pathology in manual wheelchair users and an age and sex matched able-bodied referent group, 2) improves the arm use metrics measured during daily living, and 3) determines risk factors of arm use that accelerate shoulder pathology and pain progression beyond that of natural aging. Additionally, this proposal performs a large retrospective population-based cohort study to investigate the risks of comorbidities and medication to a future clinical diagnosis of shoulder pathology or pain. Abundant evidence exists that individuals with spinal cord injury who use manual wheelchairs are much more likely than age matched able- bodied individuals to have rotator cuff pathology and/or shoulder pain. This clinical problem has been receiving attention for decades, yet shoulder pain and dysfunction continues at unacceptably high rates. To maintain the health and independence of a population that relies on their upper extremities for all activities of daily living, our objective is to define the natural history of rotator cuff disease in MWC users with the long-term goal of advancing evidence-based guidelines to decelerate the disease progression. The rate of pathology progression is largely unknown for MWC users, especially early in the disease when nonsurgical interventions may be appropriate. Aim 1 addresses this need by tracking the progression of rotator cuff tendinopathy, partial tears, and pain worsening while quantifying the effect of sex, SCI lesion level, and time since SCI. Inarguably, higher rotator cuff pathology rates among manual wheelchair users is attributable to the altered shoulder function during daily living. However, clinical care would be improved if it was known which extrinsic factors of daily arm use differentiated MWC users whose pathology progression was more accelerated from those whose pathology did not progress or progressed more slowly. Aim 2 uses wearable sensor technologies to determine the association between daily arm use (arm posture, repetitive movement, and recovery) and progression of rotator cuff pathology and pain. Intrinsic factors, including comorbidities and medication use, have been associated with tendon pathology in the able-bodied literature but they are unstudied in the spinal cord injured population. Therefore, Aim 3 will evaluate the contribution of comorbidities and medication use to the onset of rotator cuff pathology and pain in a population-based cohort. By studying factors that differentiate those who have increased rates of pathology progression from those with stable or improving pathology; actionable intrinsic and extrinsic risk factors can be defined. These steps are fundamental for providing a basis for patient education and rehabilitation strategies. By focusing on the early stages of rotator cuff pathology, this study is likely to lead to rehabilitation strategies to implement prior to the development of shoulder dysfunction among individuals who rely on their shoulders for independence.