Rotator Cuff Tear

ROTATOR CUFF TEAR

 

 

 

Anatomy and function

The rotator cuff is a group of four muscles that suround the humeral head  – Supraspinatus, Infraspinatus, Teres Minor and Subscapularis.  The muscles function to provide rotation of the humerus on the glenoid and primarily compression of the humeral head into the glenoid concavity providing stability and concentric glenohumeral joint articulation.

The Supraspinatus muscle is the primary superior cuff muscle.  Its effective strength is assessed by positioning the arm in 90 degrees of elevation in the plane of the scapula and in internal rotation (so that the supraspinatus lies over the top of the humeral head) and then noting the amount of isometric elevation torque that can be generated.

The Infaspinatus is the primary posterior cuff muscle, assisted to a degree by Teres Minor. Between them they provide the only external rotation power ( except posterior deltoid in some situations)  Its effective strength is assessed by positioning the arm in neutral and slight elevation in the plane of the scapula with the elbow flexed to 90 degrees and then noting the amount of isometric external rotation torque that can be generated.

The subscapularis muscle is the primary anterior muscle.  Its effective strength is assessed by either positioning the arm in maximal internal rotation (with the elbow flexed to 90 degrees and the hand behind the back) and then noting the amount of isometric internal rotation torque that can be generated , the “ Lift Off ” test; or by compressing  the abdomen whilst holding the elbow as far forward as possible  (Abdominal Press Test).  Both are intended to minimize the contribution of other internal rotators such as pectoralis major, the Latissimus Dorsi and Teres Major and then noting the amount of isometric internal rotation torque that can be generated.

Pathogenesis and Aetiology

A tear may result suddenly from a single traumatic event or develop gradually.  Common traumatic causes are:

  • A. A fall onto an outstretched arm.
  • B. Injury while trying to lift or catch a heavy object.
  • C. Extremes of external rotation and abduction adopted in sports such as tennis, baseball, basketball.
  • D. During shoulder (Gleno-Humeral joint) dislocation

A progressive tear is considered to be a combination of extrinsic impingement from surrounding structures eg; subacromial spurs and intrinsic factors from within the tendon itself ( degenerative changes, impaired blood supply, inflammatory disease)

Important intrinsic factors are degeneration of the substance of the tendon, e.g; disorganization and fragmentation of the collagen architecture and the hypoperfusion that increase with age.  Tears can be categorized into full or partial thickness.

 

 

 

 

 

 

 

 

 

 

 

Signs and Symptons

Typically pain is felt antero-laterally in the deltoid muscle area of the shoulder,  which radiates down the side of the arm. Pain while sleeping on the affected side.
Pain increasing with overhead activity Weakness of the arm particularly during activities above shoulder height  eg combing ones hair.
Catching, grating or cracking on movement. Atrophy or thinning of the muscles around the shoulder.

Diagnosis

This is partly on physical examination and partly imaging such as MRI or Ultrasound (US) scans.   An MRI can distinguish between inflammation, a full thickness, complete tear of the tendon and a partial tear. Ultrasound in skilled hands can proide similar information but cannot “penetrate” to see deeper structures within the shoulder.  In some circumstances an arthorgram, in which local anaesthetic and die is injected into the joint can be useful.  Once a tear has occurred, treatment options include:

 

  1. Rest with limited overhead activity,
  2. Anti inflammatory medication,
  3. hydrocortizone injection,
  4. strengthening exercises and physiotherapy.

 

Surgical options include debridement of rotator cuff and rotator cuff repair.

 

Once a tear has occurred, treatment options include:

  1. Rest with limited overhead activity,
  2. Anti inflammatory medication,
  3. hydrocortizone injection,
  4. strengthening exercises and physiotherapy.

 

Surgical options include debridement of rotator cuff and rotator cuff repair.

 

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