Acromioclavicular joint osteoarthritis

Acromioclavicular joint osteoarthritis causes shoulder tip pain and impairs shoulder movement. Arthroscopic AC joint resection and subacromial decompression completely cure the patient.

 

Acromioclavicular (AC) Joint Injury or Separation

Acromioclavicular (AC) joint injury or AC joint separation is classified most commonly into 6 grade system described by Rockwood (1998). Injury classification system takes into account not only the acromioclavicular joint itself, but also the coracoclavicular (CC) ligament, the deltoid and trapezius muscles and the direction of dislpacement of the clavicle with respect to the acromion.

Type I

  1.   Acromioclavicular(AC) ligament : mild sprain
  2. Joint capsule: intact
  3. Clavicle not elevated with respect to the acromion
  4. CC ligament: intact
  5. Deltoid muscle: intact
  6. Trapezius muscle: intact

 

Type II: 

1.     AC ligament: ruptured

2.     Joint capsule: ruptured

3.     Clavicle elevated but not above the superior border of the acromion

4.     CC ligament: sprain

5.     Deltoid muscle: minimally detached

6.     Trapezius muscle: minimally detached

 

Type III  

  1. AC ligament: ruptured
  2. Joint capsule: ruptured 
  3. Clavicle elevated above the superior border of the acromion but coraclavicular 

         distance is less than twice normal 

  1. CC ligament: ruptured. 
  2.  Deltoid mucle: detached. 
  3.  Trapezius muscle: detached.

Type IV:

  1.   AC ligament: ruptured.
  2.   Joint capsule: ruptured.
  3.   Clavicle displaced posteriorly into trapezius
  4.   CC ligament: ruptured
  5.   Deltoid muscle: detached
  6.   Trapezius muscle: detached

 

Type V

  1. AC ligament: ruptured.
  2.  Joint capsule: ruptured.
  3. Clavicle is markedly elevated and coracoclavicular distance is more than double normal (i.e. >25 mm)
  4. CC ligament: ruptured.
  5.  Deltoid muscle: detached.
  6.  Trapezius muscle: detached.

Ttype VI:

  1. AC ligament: ruptured
  2. Joint capsule: ruptured
  3. Clavicle inferiorly displaced behind coracobrachialis and bicep tendons
  4. CC ligament: ruptured
  5. Deltoid muscle: detached.
  6. Trapezius muscle: detached