Anterior shoulder dislocation

Aetiology:

 

This is a common traumatic sports injury. It can result from either direct trauma to the humeral head or indirect trauma, with the arm being forced into excessive abduction and external rotation. It may occur without trauma and with a sudden wrenching movement e.g. over throwing, or missing a punch in boxing.

 

History/Examination:

Acute trauma, sudden pain and may have a feeling of popping out. Look for associated axillary nerve palsy (axillary neuropraxia occurs in 5-35%). Look for a prominent humeral head and hollowing beneath the acromion and check the peripheral pulses.

Chronic dislocators may describe posterior arm pain or a ‘dead’ arm. There may be posterior capsular tightness or a redundant anterior capsule due to recurrent dislocation.

 

Associated injuries:

Treatment:

 

Kocher’s method to relocate- Reduce with traction, initial external rotation to 90°, and then internal rotation and adduction, obtain post-reduction films. This is said to be a traumatic manoeuvre which can potentially further damage the joint.

 

Recurrence of dislocation:

Younger patients have a higher content of ‘stretchy’ type III collagen in tendons and ligaments. With each passing decade collagen-producing cells progressively convert to synthesizing type I collagen, which is insoluble and more stable. The recurrence rate after conservative treatment of acute dislocations depends on age:

 

Surgical treatment:

Important issues include age, subsequent demands, activity, and pre-injury status (e.g. throwers may lose ER with operative intervention and capsular tightening, whereas footballers may not be as concerned about this.

Potentially all first time dislocations should be managed operatively to prevent the extremely high recurrence rate.

Early surgical opinion for acute:

 

Arthroscopic procedure

Select patients do well with this approach: no bony lesion or HAGL and an intact capsule. Arthroscopic techniques for reattaching the labrum can be divided into 3 categories: (1) a transglenoid suture technique (2) arthroscopically delivered and tied suture anchors and (3) arthroscopically delivered biodegradable tacs.

Advantages include that the joint is visualized, subscapularis is not affected, there is ↓ loss ROM (particularly ER) and ↓ scar. At present however, open operations seem to have slightly better outcomes than arthroscopic ones.