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Supraspinatus pathologies

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Supraspinatus tendinopathy

Definition

  • Supraspinatus lesions are the most typical tendon lesion of the shoulder
  • Indicated by positive resisted abduction
    • This indicates either the deltoid muscle or the supraspinatus
    • It is rare for the deltoid to be at fault as a lesion
      • Falling on the shoulder or direct trauma towards the shoulder may cause this however, typically in the muscle belly
    • Although supraspinatus tendinopathy is a frequent shoulder condition, to date a definitive understanding of the associated pathology remains elusive, and there is not agreement on treatment 1

Occurrence

  • Rotator cuff tendinopathy of the shoulder affects more than 80% of people over eighty years of age 2

 

Causes

  • At-risk patients
    • Heavy laborers
    • Overhead laborers 3

 

Examination

  • Resisted abduction – painful
    • If this is the only positive finding it indicates a lesion of the muscle belly underneath the acromion which is rare
  • Full passive elevation - painful
    • If the lesion is situated in the deep part of the tendon towards the acromion
  • Painful arc
    • If the lesion is situated in the superficial part of the tendon close to the bursa
  • Both full passive elevation and painful arc
    • Both deep and superficial aspects are affected
  • Slow active de-elevation – painful
    • Indicates rotator cuff pathology 4

Therapy

  • KiD exercises
    • Eccentric exercises have been promoted for many years as a positive contribution of tendinopathies, in cases such as achilles, patellar, wrist extensors and rotator cuff muscles with good clinical outcomes

 

Additional functions

  • The supraspinatus together with the other rotator cuff muscles and the biceps maintains the humerus in towards the glenoid fossa. This function is important for the stability of the shoulder during movement
  • During abduction and flexion it depresses the humeral head, keeping the humeral head centered on the glenoid, giving the deltoideus more power to perform its function
  • Each of the rotator cuff muscles work with inhibiting excessive displacing forces which are put upon the shoulder by the strong muscles affecting the shoulder.
    • An example would be pectoralis major and anterior deltoid during flexion and elevation movements.
      • The force from these movements causes the humeral head to be drawn out from the back of the glenoid fossa
      • The counterforce of the rotator cuff muscles inhibits this displacement, securing the position and giving stability to the joint.
    • Another example would be activation of the lateral deltoid during abduction which pulls the humerus up towards the acromion.
      • Without interaction of counteractivity of the supraspinatus and the long head of the biceps the arm would not be able to fully elevate/abduct, due to humerus being limited by hitting the acromion
      • With the force of supraspinatus and long head of biceps, the counterstrain is forcing the head of the humerus slightly down, so that there is space for the humeral head to rotate and thereby fully rotate for abduction

 

Considerations

  • Alterations of upper trapezius/lower trapezius, and upper trapezius/middle trapezius ratios, shoulder kinematics,and posterior capsule tightness have been associated with many shoulder disorders, correction of posterior shoulder tightness and restoration of glenohumeral joint and scapular kinematics are encouraged. Such interventions illustrate the important role of the therapist in conservative management of movement system dysfunction that may be associated with supraspinatus tendinopathy. 5 6 7 8 9 10 11

Partial rupture supraspinatus

Definition

  • Is usually indicated by both pain and weakness of resisted abduction
  • Of the rotator cuff muscles, the supraspinatus is the most likely to rupture
  • Usually the patient is usually unaware of any weakness of the muscle

Occurrence

  • 20% of population with asymptomatic shoulders show partial rotator cuff tear 12

Causes

  • Typically affects middle-age and elderly people

Examination

  • Resisted abduction – painful and weak

Patient recommendations

  • Great care should be taken with advice towards infiltrations of a partially ruptured tendon as the tendency to use the arm more when being pain-free might lead to further degradation and worsening of the condition. It is of high importance that the patient allows full rest of the arm during this time

Complete rupture supraspinatus

Definition

  • Typically, a painless presents itself as a painless weakness when attempting to lift the arm
  • In big tears the patient may be unable to abduct the arm
    • This effect is not only due to loss of power, but also in regard to loss of stabilization of the glenohumeral joint during movement which the tendon and muscle provides
  • 15% of population with asymptomatic shoulders show complete rotator cuff tear13

Causes

  • Typically affects middle-age and elderly people
  • Indirect trauma - such as a fall14
    • This may also cause rupture in patient younger than 40 years as well
    • Accounts for about 50% of cases
    • A longstanding chronic high tension of the tendon is the most common reason for rupture of the tendon
      • The fibers are worn down over time leading to increasing weakness of the tendon making it susceptible to rupturing
      • Accounts for about 50% of cases
      • A former estimation showed that 95% of rotator cuff tears are a result of a long-standing supraspinatus tendinopathy, where erosion occurs during abduction and overhead lifts as a result of impingement. The 95% factor has recently been challenged, although the mechanism is accepted in many cases

Development

  • Degradation of the tendon due to wearing over time as a result of high tension is the most common cause for rupture
  • Commonly there is an acute trauma/incident with sharp pain in the shoulder followed by an inability to lift the arm
    • The pain is severe first few day and then diminishes gradually
    • Normal activity of the shoulder is diminished following the injury
  • After some time the patient may compensate their movements by jerking the arm past the first 30 degrees of abduction and thereafter lifting the rest of the way by using the deltoid
  • The damage and limitation caused by the rupture may further develop into an immobilization arthritis after some months and a capsular pattern develops

Examination

  • Active elevation – clear limitation
    • No movement in the glenohumeral joint is seen, during the elevation most of the movement will be in the scapular rotation
  • Painful arc – during passive movement
  • Resisted abduction – Weak and painless
  • Observation – After some weeks there may be visible atrophy of the supraspinatus

Treatment

  • If the patient is young surgery should be considered
    • Although surgery cannot repair the stabilization quality of the tendinous tissue the supraspinatus will still be vulnerable to future damage

References

  1. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6253746/
  2. https://pubmed.ncbi.nlm.nih.gov/7706351/
  3. https://pubmed.ncbi.nlm.nih.gov/6825348/
  4. https://pubmed.ncbi.nlm.nih.gov/23306597/
  5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6253746/
  6. https://pubmed.ncbi.nlm.nih.gov/14560543/
  7. https://pubmed.ncbi.nlm.nih.gov/14560543/
  8. https://pubmed.ncbi.nlm.nih.gov/9617396/
  9. https://pubmed.ncbi.nlm.nih.gov/15877219/
  10. https://pubmed.ncbi.nlm.nih.gov/17224433/
  11. https://pubmed.ncbi.nlm.nih.gov/17062655/
  12. https://pubmed.ncbi.nlm.nih.gov/7822341/
  13. https://pubmed.ncbi.nlm.nih.gov/7822341/
  14. https://pubmed.ncbi.nlm.nih.gov/26265152/