Scapular dyskinesis increases the risk of future shoulder pain by 43% in asymptomatic athletes

First and foremost let me wish everyone a very Happy New Year, albeit a bit delayed, but still I hope 2018 will be a great year for each and everyone of you! 🙂

I do apologise for a quiet blog last month as I was doing a bit of traveling myself and of course that was followed by the holiday season towards the end of the year. But it is fair to say that the twitter sphere was relatively quiet as well in the month of December. It sure has begun to liven up again in the new year.

So the first post is on a SR and M-A on scapular dyskinesis as titled above. This review was actually published in July last year, 2017, but it has now been made open access which is great news! It has also subsequently been republished in print in the January 2018 BJSM copy.

Open access: YES

Published first: 22 July 2017

Published in print: 1 January 2018

As you know scapular dyskinesis has received a lot of attention in the physio world in recent years. Lots of courses and experts seemed to emphasise the importance of diagnosing and treating scapular dyskinesis in shoulder pain patients. However some have questioned such an approach due to the lack of good quality evidence to support such a claim.

And when we get a SR with a title like this one, it can be easy to jump to a rather simplistic conclusion that this lays to rest the discussion of whether or not we should focus on treating scapular dyskinesis in our patients. As I have learned, we cannot just take results of research studies at face value without analysing them deeper and in a meaningful clinical context. So I have tried to highlight a few points that we need to consider in relation to the title and conclusion of this SR.

Background

  • This is the FIRST ever SR to investigate whether scapular dyskinesis in asymptomatic athletes increases the risk of developing future shoulder pain
  • Previous studies have shown an association between scapular dyskinesis and shoulder pain BUT they were not able to tell us if scapular dyskinesis CONTRIBUTED to shoulder pain or that they were a consequence of shoulder pain.
  • Scapular dyskinesis is common (54%) in asymptomatic overhead athletes.(Burn et al, 2016)

  • Scapular dyskinesis is associated with poorer outcome in patients with shoulder pain.

Results

  • Five studies were included with a total of 419 athletes
  • 35% of athletes WITH scapular dyskinesis experienced shoulder pain during the follow-up
  • 25% of athletes WITHOUT scapular dyskinesis experienced shoulder pain at follow-up
  • The presence of scapular dyskinesis at baseline indicated a 43% increased risk of a shoulder pain event over a 9 to 24 months follow-up (RR=1.43, 95% CI 1.05 to 1.93).

bjsports-2018-January-52-2-102-F4.large

Discussion

  • “Scapular dyskinesis MIGHT be considered a ‘culprit’ rather than a ‘victim’ in some cases of shoulder pain.”
  • “However, these results should be interpreted with caution due to the variance in the 95% CIs, methodological heterogeneity and some risk of bias across the included studies.”

A Closer Look at the Results:

Scap dys edit 1

  • The McKenna study used a different measurement of scapular dyskinesis when compared to the rest, which may explain the difference in their results.
  • IMPORTANT TO NOTE that if McKenna was excluded from the meta-analysis, the remaining studies found only a 28% increased risk of developing shoulder pain in athletes with scapular dyskinesis, this result was not statistically significant (RR=1.28, CI 0.93 to 1.76)
  • Therefore caution should be taken when interpreting the results

Scap dys edit2.jpg

  • The Shitara study was the only study which showed a contrasting result to the rest.
  • This MAYBE due to a MUCH STRICTER classification of shoulder pain used in that study (ie. a complete withdrawal from participation in training or competition of greater than 7 days)
  • Excluding the Shitara study increased the RR and narrowed the 95% CI for increased risk of shoulder pain in asymptomatic athletes with scapular dyskinesis (RR 1.54, 95% CI 1.12 to 2.10).
  • “This analysis suggests that scapular dyskinesis may not be a risk factor for injuries that require complete withdrawal from short-term participation, that is, severe and disabling injuries. It may be a more important risk factor for lower grade shoulder injuries.”

Mechanism

  • The mechanism of how scapular dyskinesis causes shoulder pain is not clear at present
  • We also do not yet know if scapular dyskinesis is a DIRECT or INDIRECT contributing factor for shoulder pain
  •  As a DIRECT factor, some THEORIES suggest that scapular dyskinesis:
    • Causes a reduction of subacromial space leading to subacromial pain syndrome
    • Causes a reduction of rotator cuff strength causing tendon overload
  • As an INDIRECT interactive factor:
    • Scapular dyskinesis was NOT found to be a risk factor IN ISOLATION, but increases the risk when in the presence of excessive increases in load
    • Some view it NOT AS A RISK FACTOR but as an early warning indicator of future shoulder pain

Screening

  • In terms of predicting an injury, the findings from this current review suggest that the diagnostic accuracy is not far from a coin toss at 54%!
  • The presence of scapular dyskinesis could be used as part of a battery of tests including other known predictive risk factors such as glenohumeral rotational range, rotator cuff strength and previous injury to determine an individualised injury risk profile

Injury Prevention

  • At present it is not known if addressing scapular dyskinesis will reduce injury risk BECAUSE:
    • Two recent SRs showed INCONSISTENCIES in outcomes of scapular-focused interventions on scapular positioning (Bury et al, 2016; Reijneveld et al, 2017)
    • As mentioned earlier we do not yet know if scapular dyskinesis is a DIRECT or INDIRECT factor
    • Treating scapular dyskinesis in ISOLATION is unlikely to be effective
    • Successful should injury prevention programmes (Swanik et al, 2002; Andersson et al, 2016) have used a combination of scapular focused AND non-scapular focused interventions. It is impossible to differentiate in these studies which is more effective.

Future studies:

  • Should seek to clarify if scapular dyskinesis is DIRECTLY or INDIRECTLY related to the mechanisms of shoulder pain
  • Should investigate if scapular focused treatment can effectively reduce injury risk
  • Participants should be blinded to their baseline assessment results and potential confounding factors addressed with clear between-group analysis at baseline and end point

What do all these findings MEAN CLINICALLY?:

  • NOW we know that athletes with scapular dyskinesis have 43% greater risk of developing shoulder pain than those without scapular dyskinesis BUT
  • The findings do not allow us to predict accurately who will go on to develop shoulder pain, the diagnostic accuracy is NOT MUCH BETTER than a coin toss at 54%
  • Screening for scapular dyskinesis MAY be more useful as part of a battery of tests that includes other known risk factors (glenohumeral rotational range, rotator cuff strength and previous injury)
  • Based on current evidence, it appears that clinicians should continue to consider using scapular focused interventions as part of an injury prevention programme
  • Scapular dyskinesis MAY be seen as an early warning sign, acting an an INDIRECT interactive risk factor, it MAY alert clinicians to monitor other risk factors such as exccessive increase in LOAD

That’s my take on this review paper. I’ve tried my best to pick out the more important points and interpret them in a clinically meaningful way. BUT you should always read the full paper if you can. I must say the authors did an excellent job in the discussion section and highlighted all the relevant limitations of the paper and adopted a balanced approach in my opinion.

Please click on the link below to read the full article:

Hickey, D. et al (2017) Scapular dyskinesis increases the risk of future shoulder pain by 43% in asymptomatic athletes: a systematic review and meta-analysis. BJSM.

 

 

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