Anterior dislocation
- Shoulder is one of the commonest joints to dislocate due to:
- Shallowness of glenohumeral joint
- Range of movement
- Ligamentous laxity or glenoid dysplasia
- Vulnerability of joint
- Dislocation usually caused by fall on hand
- External rotation in abduction levers the head of the humerus out of
the glenoid socket
- Joint capsule is often torn
- Glenoid labrum may be avulsed (Bankart lesion)
Clinical features
- Bimodal age distribution
- First peak occurs in young adult men after significant trauma
- Second peak occurs in elderly women after less violence
- Pain is often severe
- Arm usually held in abduction and externally rotated
- All movement is restricted
- Lateral outline of shoulder is flattened
- Bulge may be felt below clavicle
- X-ray shows overlapping of humeral head and glenoid fossa
- Head of humerus seen below and medial to the joint
- X-ray is mandatory to exclude an humeral fracture
Treatment
- Numerous methods of reduction have been described
- May be reduced by simple traction / countertraction in slight
abduction
- Kocher's method
- Elbow flexed to 90 degrees
- Arm slowly rotated laterally to 75 degrees
- Elbow lifted forward and arm rotated medially
- X-ray taken to confirm reduction and exclude fracture
- Arm rested in sling for 2-3 weeks
Complications
- Axillary nerve injury
- Vascular injury
- Fracture-dislocation
- Shoulder stiffness
- Unreduced dislocation
- Recurrent dislocation
Posterior dislocation
- Posterior dislocation is rare
- Accounts for less than 2% of shoulder dislocations
- Due to indirect forces resulting in internal rotation and adduction
- Seen following convulsions or electric shocks
- Injury is easily missed
- AP x-ray may appear 'normal'
- If any doubt regarding diagnosis then CT is useful
Bibliography
Cicak N. Posterior dislocation of the shoulder. J Bone
Joint Surg Br 2004; 86: 324-332.
Cutts S, Prempeh M, Drew S. Anterior shoulder
dislocation. Ann R Coll Surg Engl 2009; 91: 2-7
Jennings S, Cohen B. Common injuries of the shoulder.
Hosp Med 2002; 63: 681-683 |