Shoulder Impingement is a Myth!

Therapy is such a strange field in that it seems to change a bit every day. At the same time we seem to go through phases as clinicians in terms of what works and what doesn't. Whether this occurs because we streamline our techniques as we gain experience, are exposed to new evidence/methods, or are confronted with different types of patients isn't always clear. Something taken as law yesterday, might very quickly fall under scrutiny as the evidence becomes better. This is also true with some of the most common diagnoses. One in particular stands out above the rest: Shoulder Impingement Syndrome.

Shoulder impingement syndrome originally described an apparent structural flaw in the shape of the acromion process. The diagnosis then evolved to include mechanical flaws such that soft tissues are being pinched between the acromion and the head of the humerus during shoulder elevation. The first version of impingement syndrome has essentially been disproven via surgical studies comparing acromion resection and bursectomy vs bursectomy alone; both groups improved similarly without significant difference between the groups (Kolk et al. 2017). This seems to debunk the idea that the shape of the acromion could be at the root cause of shoulder pain. In the case of the second type of impingement, the soft tissues under the acromion exist in a compressed state, and are being "pinched" in healthy shoulders as well as painful ones (Girish et al. 2011, Frost et al. 1999). Essentially we have found that these tissues are designed to be compressed, and pain occurs when the shoulder becomes intolerant to such stress for one or more of many possible reasons.

Thus we are left with a new diagnosis and method of looking at the shoulder: Rotator Cuff Related Shoulder Pain (RCRSP) (Lewis et al. 2018). If this sounds like a non-descriptive garbage term, it is 100% just that. What's more, is that's OK. For years, l

eading experts in the ortho world have been pushing to do away with special testing for painful tissues in the shoulder due to poor specificity and sensitivity (Lewis et al. 2020). This new diagnosis is more in line with pain science and tissue loading models for physical therapy. These models don't altogether throw out mechanics and motor control, but place more emphasis on the need to apply an appropriate amount of stress to a painful shoulder to induce healing and analgesia, while reducing cortical inhibition and apprehension.

Additionally, this new diagnosis de-emphasizes the idea that some part of the body is broken, or that the individual must develop a complex over whether they are moving just perfectly or not in order to avoid pain. Of course there are instances where a structural fault must be repaired to restore function, i.e. massive cuff tear with rotator cable i

nvolvement. Additionally, movement correction and motor control exercises have been heavily backed by evidence to play a crucial role in the early phases of rehab. RCRSP simply reveals that there are more mechanisms at play than simply mechanical factors. Shifting focus away from pathological tissues is also less likely to create nocebo's in our patients, painting a picture that something simply hurts and can get better rather than stating that something hurts due to a mechanical or anatomical issue.

Bottom line, it's time we start the movement and update our terminology in a way that not only guides our treatment, but also puts our patients' interests first.

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