Freehand Ultrasound to Evaluate Scapular Kinematics in People With Paraplegia

Shoulder pain is very common in people with spinal cord injury (SCI). Persons with high-level paraplegia have higher chances to suffer shoulder pain and injury than those with lower-level paraplegia due to the shoulder muscle imbalance. As people with SCI overuse the shoulder during routine daily activities, the onset of pain or injury lead to increased healthcare expenses, limitation in activity, depression, decreased participation, and reduced quality of life. One of the main reasons of shoulder pain is believed to have a altered scapular movement. To clarify the mechanism of the shoulder pain and injury, comprehensive understanding of three-dimensional scapular kinematics is required. Ultrasound is a low-cost and non-invasive imaging system and has been used to diagnose the shoulder pain and injury in individuals with SCI. A freehand ultrasound (FUS) combining ultrasound with motion capture system to evaluate scapular movement was developed and presented favorable results in able-bodied population. The purpose of this study is to compare the FUS and widely used skin-based method against a radiographic based gold standard in people with paraplegia, and to elucidate the relationship among scapular movement and shoulder pain, pathology. This study will also allow us to gain more understanding of how level of injury influences the scapular behavior during functional activities. The investigators believe more severe shoulder pain and pathology will be associated with greater abnormal scapular movement. The investigators also believe that people with high-level paraplegia will have greater scapular abnormality than people with low-level paraplegia during arm elevation and weight relief raise tasks. By completing this study, the investigators will expect to deliver a reliable and valid tool to evaluate scapular movement and gain a better understanding how the altered scapular movement is related to shoulder pain and pathology. The investigators will also learn how the level of injury affects the scapular behavior during functional activities. The results of this study may help the shoulder pain management leading to the improvement in the quality of life of individuals with SCI.