The Impact of Shoulder Immobilization by Orthoses on Human Joint Biomechanics and Inter-joint Coordination

Shoulder joint orthoses are commonly used for patients with shoulder disorders to stabilize and protect shoulder joint after injury or surgery. These devices maintain proper anatomical alignment of the shoulder joint and surrounding soft tissues, reducing pain, facilitating proper recovery, and preventing further injury. Commonly used shoulder orthoses include shoulder sling, abduction brace, and figure-of-eight shoulder brace. The appropriate orthosis is selected based on patient's specific clinical needs, and it should be worn for an appropriate duration to avoid over or inadequate shoulder immobilization. When patients wear shoulder orthoses during daily activities, such as sit-to-stand, level walking, climbing stairs, or overcoming obstacles of a certain height, the immobilized shoulder reduces reciprocal arm swing, altering body's balance mechanism and potentially increasing the risk of falls. Different shoulder orthoses with various shoulder position affect human motor coordination and balance to varying degrees. Therefore, assessing the changes in body movements caused by shoulder immobilization with orthoses can provide crucial clinical information to aid in clinical decision-making. This study utilizes stereophotogrammetry to measure and analyze subjects' motion changes while their shoulders are immobilized with orthoses. It aims to understand the biomechanical changes when subjects participate in static balance tests and dynamic activities. Through corresponding biomechanical analyses, including kinematics, dynamics, and joint coordination, the study seeks to understand the extent of the impact of shoulder orthoses on human movements. This information would serve as important reference data for subsequent clinical decisions regarding whether to use orthoses or not, the duration of use, and the suitability of the orthoses for patients of different ages.