Current views of scapular dyskinesis and its possible clinical relevance

Key Points

1. A qualitative examination to establish the presence or absence of a scapula contribution to shoulder dysfunction is currently the best option available to clinicians.
2. Potential causative factors should be assessed during the physical examination that includes a pathoanatomic assessment, but this should not be the primary focus of the examination.
3. Rehabilitation approaches should prioritize a motor control approach as the primary focus rather than isolated strengthening exercises.

BACKGROUND & OBJECTIVE

The scapula is critical to effective upper limb function and loss of scapula function has implications for shoulder injury, symptoms, and upper limb function. While aspects of scapula assessment are becoming better understood (1), the clinical importance of the scapula’s influence on shoulder function remains unclear.

The aim of this study was to provide a framework for the assessment and treatment of scapula dyskinesis (SD) in the context of what is now known about its role in symptoms and pathology and how we assess and rehabilitate scapula dysfunction.

The scapula is critical to effective upper limb function and loss of scapula function has implications for shoulder injury, symptoms, and upper limb function.

A more proprioceptive ‘feedback’ approach to rehabilitation of the scapula may be more successful in re-establishing scapula control within the kinetic chain.

METHODS

The authors provided a clinical viewpoint on current views of scapula dyskinesis and provided a narrative review combined with expert opinion on its clinical relevance.

RESULTS

The authors present a current, evidence-informed framework for scapula terminology and assessment, evaluating its contribution to symptoms, and outline a good case for reconsidering the role of strengthening alone in the rehabilitation of SD.

Reconsidering the Clinical Examination

SD is an impairment, not a diagnosis. Therefore, clinical assessment should not focus on diagnostic tests for a pathoanatomic cause, but rather on a qualitative assessment of position and motion. The authors suggest the following model could be used as a framework for assessment of scapula function:

1. Establishing the presence or absence of scapula dyskinesis

Is achieved by observing scapula motion during forward flexion or abduction over several repetitions, with weights if necessary (2). The authors recommended including in the assessment three specific muscle tests for scapula function (serratus anterior, middle trapezius and rhomboids). Weakness or movement of the scapula during the tests suggests scapula muscle weakness.

2. Establishing the relationship between dyskinesis and symptoms

Application of the following scapula correction tests during provocative movements can help assess the contribution of SD to symptoms and function and provide guidance for rehabilitation (See Table 1).

3. Evaluating possible causative factors

When the SD is linked to clinical symptoms, identifying whether the SD is pathoanatomic (e.g. clavicle or scapula fracture, AC joint injury, nerve injury) or pathophysiologic (e.g. muscle imbalance, inhibition, tightness, weakness) can help guide treatment (see Figure 1).

Reconsidering Treatment

Treatment of scapula dyskinesis has focused on improvement of mobility and strength on the assumption these factors contribute to faulty motion, however interventions directed at scapula mobility and strength have shown little change in scapula motion (3).

Exercises that target specific scapula muscles were suggested primarily based on EMG studies conducted on asymptomatic individuals in non-functional positions (vertical, prone or supine) on the assumption that these muscles work in isolation to produce movement, which is known not to be the case. It is also possible that these muscles function differently in the presence of symptoms. It would appear then that evidence is not yet convincing that strengthening specific muscles based on EMG studies of muscle activation influences scapula dyskinesis.

LIMITATIONS

• This was a clinical viewpoint paper. As such, evidence and expert opinion was presented to support the authors views (both authors are well qualified to do so).

• Despite the non-systematic approach (appropriate in a clinical viewpoint paper), they present a reasoned summary with clinical applications that are supported by the evidence presented.

CLINICAL IMPLICATIONS

If mobility and strength are not the answer to correcting scapula dyskinesis, perhaps scapula dysfunction is more related to motor control. Motor control is a product of sensory perception and processing and includes integration of visual, vestibular and other sensory information. The authors point out that the scapula can’t be seen due to its location on the posterior chest wall and this lack of visual feedback may contribute to alterations in motion.

Conscious correction (muscle ‘pre-setting’), visual, auditory and kinaesthetic feedback have all been shown to improve scapula position and muscle activity. The authors postulate that a more proprioceptive ‘feedback’ approach to rehabilitation of the scapula may be more successful in re-establishing scapula control within the kinetic chain.

Expert consensus papers have suggested scapula motor control programmes include functional movements that enhance activation of scapula muscles through synergistic activation of lower limbs and trunk. An example of such a programme should include:

• Short lever progressions

  • Arms adducted vs abducted or elevated
  • Aim is to establish proper scapula positioning early in rehabilitation
  • When good control is established, lever length can be gradually increased based on symptom response.
  • Recommended dosage progressions included:
    • 1-2 sets, 5-10 repetitions with no external resistance
    • Progress to a goal of 5-6 sets of 10 repetitions before adding resistance
    • Resistance should begin with light free weights (1-2kg maximum) and progress to elastic resistance with monitoring of load

• Sitting and standing preferred over prone or supine exercises

• Target impairments in order of:

  • Mobility
  • Motor control
  • Strength (if necessary)
  • Endurance

• Utilize longer lever manoeuvres later in rehabilitation

• Advance to plyometric based manoeuvres just prior to discharge

+STUDY REFERENCE

Sciascia A, Kibler WB (2022) Current Views of Scapular Dyskinesis and its Possible Clinical Relevance. Int J Sports Phys Ther. 2;17(2):117-130.

SUPPORTING REFERENCE

1. Kibler WB, Sciascia AD. Introduction to the second international conference on scapular dyskinesis in shoulder injury-the 'scapular summit' report of 2013. British Journal of Sports Medicine. 2013;47(14):874.
2. Tate AR, McClure P, Kareha S, Irwin D, Barbe MF. A clinical method for identifying scapular dyskinesis, part 2: Validity. Journal of Athletic Training. 2009;44(2):165-73.
3. Rosa DP, Borstad JD, Pogetti LS, Camargo PR. Effects of a stretching protocol for the pectoralis minor on muscle length, function, and scapular kinematics in individuals with and without shoulder pain. J Hand Ther. 2017;30(1):20-9.