Subacromial impingement syndrome is the most common diagnosis for shoulder pain in adults and remains one of the most common reasons patients seek care from physicians and Physical Therapists. Shoulder impingement may occur secondary to functional and structural changes within the shoulder joint. Individuals with these symptoms often present with weakness in their rotator cuff and shoulder blade muscles which can lead to abnormal forces being placed upon the shoulder joint and its’ tendons. Previously, the shape of one of the shoulder bones (acromion) was thought to predict who may require a surgical decompression of the shoulder, but new research is challenging the importance of this space.
Park and colleagues conducted a review of the available research on the subacromial space and its’ relationship to shoulder pain in adults (Scientific Reports. 2020). Authors included 15 studies on close to 800 participants. They reported no significant association was found between the amount of structural space and the presence of shoulder pain. The researchers concluded treatment interventions including surgery should not focus only on improving subacromial space. This also may help explain, in part, the lack of difference between Physical Therapy, including manual therapy and strengthening exercises, and surgery for treatment of subacromial impingement syndrome.