Application of subacromial Bursa replacement implant designed for treatment of rotator cuff tear in the shoulder biomechanical model

Rotator cuff arthropathy (RCA) accompanied by rotator cuff tear (RCT) is on the rise globally due to aging population, increased involvement of elderly in jobs requiring muscle strength, and participation in sports activities by people of all ages. RCT is a common orthopedic problem that disrupts shoulder functions and causes pain. It impairs the physiological biomechanical function of the shoulder and leads to RCA. The aim of the treatments is to restore the ideal biomechanical function of the shoulder joint while preserving it. A prototype implant was designed to prevent or reduce the changes caused by RCT in the glenohumeral joint. Additionally, the efficacy of the developed computer simulation model in explaining changes in shoulder biomechanics in different situations was intended to be demonstrated. In the study anatomical and biomechanical characteristics of the structures in the shoulder were defined, and a shoulder simulation model was created in MSC ADAMS program. Four different tear models were created by making changes according to each pathology in the healthy shoulder simulation model. After the results were confirmed with the literature, the changes obtained by applying the prototype to these four different RCT models were examined. The data obtained with the prototype were compared with the data obtained without the prototype. The data obtained from the healthy shoulder and five models with four different tear models are compatible with the biomechanical data in the literature and can be verified. This shows that the computer simulation model is a successful and applicable biomechanical model. An increase in the abduction angle was observed in all tear models after the prototype was applied. Additionally, a decrease in the force on the glenoid was observed in all tear models, indicating a protective effect of the prototype on the glenohumeral joint. The designed prototype is a potential joint-protecting implant that can provide function by increasing the abduction angle.