Project Summary/Abstract Shoulder pain and joint disease is a serious threat to health and mobility for manual wheelchair users living with spinal cord injury. There are subsequent implications for functional independence, quality of life, caregiver burden, and healthcare utilization. In particular, rotator cuff tears are devastating for these individuals as the usual clinical course (repair) is not typically viable. Their upper extremities have become their primary means of mobility, and post-surgical shoulder immobilization is impractical. As such, it is critical that shoulder joint health is preserved for this population. In order to address the major challenges of preventing shoulder disease and dysfunction progression for manual wheelchair users, we need to assess the impact of and need for various interventions relative to rotator cuff soft tissue health. In addition to inverse dynamic calculations of joint torques or electromyographic measures, measuring the impact of interventions on rotator cuff soft tissue compression is an important advancement in mechanistic understanding and outcomes assessment. Our proposal will combine existing data sets from the University of Minnesota (20 precise 3D shoulder reconstructions including soft tissue) and Mayo Clinic (10 participants’ precise 3D shoulder kinematics during wheelchair propulsion) to measure rotator cuff compression for 200 unique combinations of shoulder geometry and kinematics. Aim 1 will “Characterize the effect of anatomical features and movement patterns on rotator cuff tendon compression during manual wheelchair propulsion”. Clinicians and transformational scientists need to know the relative impacts of motion and anatomy/geometry on rotator cuff stresses during wheelchair propulsion. Outcomes of this investigation will inform both mechanistic investigations and clinical trials assessing preventive interventions. In addition, methods to directly assess soft tissue impact are labor- and technology-intensive. Our proposed Aim 2 will “Determine the capability of low-fidelity models to predict in vivo tendon compression during manual wheelchair propulsion” by directly comparing high- and low-fidelity techniques. Successful completion of this project will determine the necessity or benefit of labor-intensive, subject-specific models over lower fidelity alternatives in studying rotator cuff tendon injury mechanisms, and preventative outcomes. This knowledge can then be applied extensively in future work by our group and others, including assessment of transfers and other functional activities. Appropriate sample sizes for future work can also be planned with the knowledge gained through this proposed project. This project provides a unique opportunity for collaboration between experienced investigators and to combine existing data to determine relative utility of various approaches for larger scale investigation planning. Our approach is responsive to the NICHD Notice of Special Interest (NOT-HD-20-200) in that it leverages valuable existing data to advance understanding of shoulder soft tissue disease and planning for future investigations by our multidisciplinary groups and others.

Project Narrative Shoulder pain in people living with spinal cord injury is a serious threat to public health, with implications for functional independence, quality of life, caregiver burden, and healthcare utilization. To better understand shoulder pain, researchers have used musculoskeletal models to understand how muscle tendons may be injured during daily activities. Our investigation will use secondary analysis of existing data to understand the relative impact of anatomy versus movement patterns of the shoulder on the muscle tendon during wheelchair propulsion.