Scapular Dyskinesis | Diagnosis & Treatment for Physios

Introduction & Epidemiology

Scapular dyskinesis (which may also be referred to as SICK scapula syndrome) is an alteration or deviation in the normal resting or active position of the scapula during shoulder movement. Sometimes, scapular dyskinesis is also referred to as SICK scapula, which is an acronym for Scapular malposition, Inferior medial border prominence, Coracoid pain and malposition, and dysKinesis of scapular movement. For most people, the scapula moves in abnormal ways due to repetitive use of the shoulder. For this reason, one might already be tempted to ask if scapular dyskinesis is a functional adaption or a pathological pattern we see in patients with shoulder pain.

According to McClure et al. (2011), the scapula displays the following movements including their average degrees of movement (including the standard deviation):

An important aspect when looking at the movement of the scapula is the scapulohumeral rhythm – or in other words – how much does the scapula move in relation to the humerus during arm elevation? Watch the following video in order to learn more about which movements in the shoulder girdle take place in a ‘healthy’ scapula according to the literature:

Seventy-seven percent of physiotherapists believe that a scapulohumeral ratio of 1:2 is normal. This is what we learn in school and what we display in our videos as well (Kirby et al. 2007). However, the 1:2 ratio was first described in 1944 in a single subject by Inman et al. (1996) and it got stuck! In reality, research shows that ratios vary considerably depending on gender, age, hand dominance, the plane of movement, bilateral or unilateral arm movement, speed of movement, different loads, different sports the patient is playing, fatigue, and pain.

So in fact, we really can’t reliably say what “normal” means!

In the following video you will learn about the function of different muscles acting on the scapula and classical ‘dysfunctions’ of the scapula described in the literature and their suspected underlying causes:

Be aware that there is a big prevalence of scapular dyskinesis in non-overhead athletes at 33% and even more in overhead athletes at 61% (Burn et al. 2016).
So in a lot of cases, scapular dyskinesis might be a functional adaption rather than a contributing factor to shoulder pathology!
On the other hand, Prezioso et al. (2018) did a cross-sectional study on 661 young asymptomatic elite swimmers and found a low prevalence of scapular dyskinesis of 8,5%.

Clinical Presentation & Examination

Examination

Kibler et al. (2002) were one of the pioneers in the classification of scapular dyskinesis. Up to today, the 4-type classification is the most commonly used method in scientific studies to determine if participants display scapular dyskinesis or not.
Watch the video if you want to learn more about the classification in detail:

In the following table, you can find an overview of the 4 different types and their clinical presentation according to Kibler et al. (2002).

Other orthopedic tests to assess scapular dyskinesis are:

• Scapular Assistance Test
• Scapular Retraction Test

Treatment

Should you focus on motor control training to improve scapular motion? McQuade et al. (2016) wrote a critical and theoretical perspective on scapular stabilization and summarize the following:

“Although some studies suggest that scapular stabilization exercises influence scapulothoracic (ST) muscle activation, it is not known whether increases in ST muscle activation or changes in activation ratios translate to any lasting kinematic pattern improvements. In total, there is little evidence to suggest that scapula motor control training can functionally affect scapula muscle activation. Learning to consciously control scapula position and using visual biofeedback appears to be good methods for immediately altering ST muscle activation or motion, yet the long-term clinical significance and transferability to daily functional tasks remain unknown.”

An RCT from Turgut et al. (2017) compared shoulder girdle strengthening+stretching exercises with strengthening+streching exercises plus the addition of scapular stabilization exercises. Although the stabilization group showed differences in external rotation, posterior tilt, and upward rotation, both groups showed improvement in self-reported pain and disability scores to the same degree. So while we might (Turgut et al. 2017) or might not (McQuade et al. 2016) be able to influence scapular kinematics, it seems that it might not be relevant for your shoulder patient’s outcome.

On top of that, Shire et al. (2017) did a systematic review and meta-analysis of six RCTs with four studies evaluating specific scapular exercise strategies and two with a specific proprioceptive strategy compared to general shoulder exercises. They state that no consistent difference was found between the treatment groups in these six studies regarding pain and function. Five of these studies were rated as moderate evidence and one as low-level evidence. For this reason, they conclude that there is insufficient evidence to support or refute the effectiveness of specific resistive exercise strategies in the rehabilitation of subacromial impingement syndrome.

In conclusion, our personal approach is to not focus too much on scapular kinematics, but rather on the strengthening of the rotator cuff and scapulothoracic musculature. You can find a graded exercise approach for scapular strengthening from early (post-operative) rehab to intermediate rehab:

Another exercise that targets the scapular muscles and at the same time strengthens the rotator cuff is the Y-lift:

Do you want to learn more about shoulder pain? Then check out our blog articles and research reviews:

• Why Shoulder Rehab should be like a Delicious Pizza
• Induce Pain to Relieve Pain in Rotator Cuff-Related Shoulder Pain?
• The Upper Traps – Over-Assessed, Overblamed, And Very Misunderstood!
• Conservative vs. Surgical Management of Patients with Rotator Cuff Tears

References

Burn, M. B., McCulloch, P. C., Lintner, D. M., Liberman, S. R., & Harris, J. D. (2016). Prevalence of scapular dyskinesis in overhead and nonoverhead athletes: a systematic review. Orthopaedic journal of sports medicine, 4(2), 2325967115627608.

Inman, V. T., & Abbott, L. C. (1996). Observations of the Function of the Shoulder Joint. Clinical Orthopaedics and Related Research (1976-2007), 330, 3-12.

Kirby, K., Showalter, C., & Cook, C. (2007). Assessment of the importance of glenohumeral peripheral mechanics by practicing physiotherapists. Physiotherapy Research International, 12(3), 136-146.

McClure, P. W., Michener, L. A., Sennett, B. J., & Karduna, A. R. (2001). Direct 3-dimensional measurement of scapular kinematics during dynamic movements in vivo. Journal of shoulder and elbow surgery, 10(3), 269-277.

McQuade, K. J., Borstad, J., & de Oliveira, A. S. (2016). Critical and theoretical perspective on scapular stabilization: what does it really mean, and are we on the right track?. Physical therapy, 96(8), 1162-1169.

McClure, P., Tate, A. R., Kareha, S., Irwin, D., & Zlupko, E. (2009). A clinical method for identifying scapular dyskinesis, part 1: reliability. Journal of athletic training, 44(2), 160-164.

Preziosi Standoli, J., Fratalocchi, F., Candela, V., Preziosi Standoli, T., Giannicola, G., Bonifazi, M., & Gumina, S. (2018). Scapular dyskinesis in young, asymptomatic elite swimmers. Orthopaedic journal of sports medicine, 6(1), 2325967117750814.

Shire, A. R., Stæhr, T. A., Overby, J. B., Bastholm Dahl, M., Sandell Jacobsen, J., & Høyrup Christiansen, D. (2017). Specific or general exercise strategy for subacromial impingement syndrome–does it matter? A systematic literature review and meta analysis. BMC musculoskeletal disorders, 18(1), 1-18.

Turgut, E., Duzgun, I., & Baltaci, G. (2017). Effects of scapular stabilization exercise training on scapular kinematics, disability, and pain in subacromial impingement: a randomized controlled trial. Archives of physical medicine and rehabilitation, 98(10), 1915-1923.