Functional implications of structural “anomalies” in shoulder pain

The shoulder joint is a frequent anatomic site of musculoskeletal pain. Most middle-aged adults with shoulder pain have been diagnosed with subacromial bursitis, or subacromial impingement syndrome. Attrition underneath the acromion have been presumed to cause painful inflammation of subacromial tissues for years, but scientific evidence was limited. The real cause for subacromial pain is still unknown, which resulted in the diagnostic label “subacromial pain syndrome”. In this thesis, we focused on the effectiveness of acromioplasty in the treatment of patients with subacromial pain. We found no effect of acromioplasty over bursectomy alone on long-term shoulder pain and function. We also examined shoulder kinematics and muscle activation in patients with subacromial pain. We found an association between the size of rotator cuff tears as well as subacromial pain syndrome with shoulder kinematics, and described an increase in teres major muscle activity in subacromial pain syndrome. The project contributed to changed recommendations in guidelines regarding the treatment of subacromial pain syndrome. Our kinematic and biomechanical studies may create a biomechanical rationale for physiotherapeutic strategies targeted at the teres major muscle in the treatment of subacromial pain.