Is Your Scapula The Root Of The Problem?

R scapula lower than L and 'sticking' out more

Both my shoulders have been aching over the past few weeks, even when I was on holiday in Japan (I did not see any patients nor exercise much). I did carry a slightly heavy backpack throughout though. Anyway, it has been estimated that 67 percent of the adult population will experience shoulder pain at some point throughout their lifetime (Luime et al, 2004).

Although there are numerous factors related to the cause of shoulder pain, many clinicians attribute the presence of scapular dyskinesis (SD) as a contributing factor to shoulder pain/ problem.  

SD is defined as mal-positioning/ mal-alignment in scapular position at rest as well as during movement. Since the identification of SD is a common part of patient evaluation, it is often used to guide clinical decision making, although there is considerable debate regarding SD and shoulder pain/ problem. The evaluation is expecially common in predicting or preventing injury in over head athletes even though there is conflicting evidence regarding the link.

Some studies have shown no difference in the prevalence of SD between symptomatic and asymtomatic populations. This then raises the question of usefulness when screening for SD in patients seeking treatment for shoulder pain as well as those asymptomatic patients with SD.

Another patient -R scapula lower than L

Besides, not every clinician agrees what is the best way to classify and assess SD. Clinicians often direct their treatment towards correcting the SD which may be normal movement variability.There is also a lack of evidence to support the idea that identification and correction of SD may help to prevent or treat SD.  

The following systematic review investigated the prevalence of SD among both symptomatic and asymtomatic patients with the hypothesis that SD is a common finding that has been 'medicalized'  i.e. clinical findings suggest treatment but ultimately is a normal finding.

34 studies were found suitable out of 11,619 found. That is a lot out of material to go through.

60 percent among the subjects (total 650) in the systematic review with shoulder pain presented with SD. 48 percent of the asymptomatic (no pain) subjects (1048 total) presented with SD. Almost half of those studied presented with SD even though they were asymptomatic.

Consider the following. 2 studies in the review found that as swim training progessed, the number of swimmers presenting with SD increased with a large number of them presenting with SD at the end of the same training session. All these competitive swimmers were aysmptomatic. 

The initial perception may be that there is some weakness or compensatory mechanism that may require attention. Or it may be normal adaptation related to the overall shoulder complex that caused this change to occur especially since these athletes were competing at high level with no symptoms/ pain.

Yes, there is evidence from this review to support the high incidence of SD among athletes with shoulder pain. However, even more revealing is that there were much more subjects who had SD with no shoulder pain. The authors concluded that SD may be a normal adaptation for those participating in overhead sports and that SD is a relatively normal finding among the asymptomatic population.

So if you have SD, but no pain in your shoulders, you do not need to worry about it nor treat it.

References

Luime JJ, Koes BW, Hendriksen IJM et al (2004). Prevalence And Incidence Of Shoulder Pain In The General Population: A Systematic Review. Scand J Rheumatol 33(2): 73-81. DOI: 1080/030097403100046676

Salamh PA, Hanney WJ, Boles T et al (2023). Is It Time To Normalize Scapular Dyskinesis? The Incidence Of Scapular Dyskinesis In Those With And Without Symptoms: A Systematic Review Of The Literature. IJSPT. V18(3): 558-576. DOI: 10.26603/001c.74388.