Is there a relationship between narrowed subacromial space and shoulder pain?
Shoulder pain, especially subacromial pain (Subacromial Pain Syndrome - SAPS), is one of the most common musculoskeletal disorders. Often, a narrow subacromial space, also known as Acromiohumeral Distance (AHD), has been associated with this condition. However, scientific literature has raised doubts about the validity of this correlation. A study published in *Nature* in 2020, conducted by Park et al., addressed the issue through a systematic review and meta-analysis, aiming to clarify whether there is a relationship between AHD and shoulder pain.
The analysis focused on three key questions:
1) Is there a difference in the subacromial space (AHD) between subjects with and without shoulder pain?
The authors' first goal was to determine if there was a significant difference in the subacromial space between people with shoulder pain and those without. The result? There were no statistically significant differences between the two groups. This implies that the reduction in the subacromial space alone may not be a determining factor for pain. This result challenges the traditional idea that a reduced AHD is directly related to shoulder pain symptoms.
2) Is there a linear correlation between the subacromial space and pain and function?
The second question sought to understand whether there was a linear relationship between AHD and pain or functional disability. The results, however, were inconclusive. Although some studies reported a weak correlation, most of the literature failed to demonstrate a clear and consistent connection between the subacromial space and patient symptoms. This suggests that complex and multiple factors, rather than simply reduced AHD, may be involved in the development of pain and dysfunction associated with SAPS.
Conclusions
Narrow subacromial space does not appear to be a contributing factor to shoulder pain, and there is no clear linear relationship between AHD and symptoms. This challenges some of the traditional approaches to treating shoulder pain, prompting practitioners to consider other variables in their patient care.
Source :
Park, S.W., Chen, Y.T., Thompson, L. et al. No relationship between the acromiohumeral distance and pain in adults with subacromial pain syndrome: a systematic review and meta-analysis. Sci Rep 10, 20611 (2020). https://doi.org/10.1038/s41598-020-76704-