Third most common # in the elderly and 2nd most common in the upper limb. It is twice as common in females due to osteopenia problems:
- Elderly population, poor bone stock.
- High comminution, displacement & complexity.
- Proximity to shoulder-impairing function.
- Avascular necrosis due to damage to all blood supply to the bone, where the bone dies.
- Pull of rotator cuff muscles-displacing tuberosities.
- Stiffness – need for intensive rehabilitation.
Acromioclavicular Joint Dislocations
These are injuries of the joint between the collar bone and the acromion (a projection of the scapula bone above the shoulder). It can produce a bulge on the top of the shoulder due to prominent bone. Usually treated non-operatively it may need fixation depending on the patient and injury characteristics. Treatment involves reducing the joint back to its position and using a fixation device to hold it in place.