Acromioclavicular joint

Injury to the acromioclavicular joint is very uncommon, usually caused by fall on the outer prominence of the shoulder.

The injury may result in a partial or complete rupture of the acromio-clavicular or coraco-clavicular ligaments. Acromio-clavicular joint injuries  are divided into 3 grades depending upon their severity

Diagnosis:

Pain and swelling localised to the acromioclavicular joint indicates an injury to this joint.
Om a Grade III injury the lateral end of the clavicle may be unusually prominent. Xray with the acromioclavicular joints of both sides for comparison in the same film will show the subluxation or dislocation.


Grades of acromio-clavicular injury



Grade I: Minimal strain to acromio clavicular ligament and joint capsule

Grade II: Rupture of acromioclavicular ligaments and joint capsule

Grade III: Rupture of acromioclavicular ligament, joint capsule and coraco-clavicular ligament.

Treatment

Grades I and II injuries are treated by rest in a triangular sling and analgesics. Grade III injury in young athletic individuals is treated by surgical repair.








Type I

Sprain of acromioclavicular ligament
AC joint is intact
Coracoclavicular ligaments intact
Deltoid and trapezius muscles intact

Type I

AC joint disrupted
<50% vertical displacement
sprain of the coracoclavicular ligaments
CC ligaments intact
Deltoid and trapezius muscles intact

Type III

AC ligaments and CC ligaments all disrupted
AC joint dislocated and the shoulder complex displaced inferiorly
CC interspace greater than normal shoulder (25-100%)
Deltoid and trapezius muscles usually detached from the distal clavicle

Variants: pseudodislocation through an intact periosteal sleeve, physeal injury, coracoid process further

Type IV

AC and CC ligaments disrupted
AC joint dislocated and clavicle displaced posteriorly into or through the trapezius muscle
Deltoid and trapezius muscles detached from the distal clavicle.

Type V

AC ligaments disrupted.
CC ligaments disrupted
AC joint dislocated and gross disparity between the clavicle and the scapula (100-300%)
Deltoid and trapezius muscles detached from the distal half of clavicle.

Type VI

AC joint dislocated and clavicle displaced inferior to the acromion or the coracoid process
AC and CC ligaments disrupted
Deltoid and trapezius muscles detached from the distal clavicle.


TREATMENT OPTIONS FOR TYPES I- II ACROMIOCLAVICULAR JOINT INJURIES

Non operative: ice and protection until pain subsides in 7-10 days
Return to sports as pain allows (1-2 weeks)
No apparent benefit to the use of specialised  braces

Type II Operative treatment

Generally reserved only or the patient with chronic pain.
Treatment is resection of the distal clavicle and reconstruction of the coracoclavicular ligaments

Type III-IV

Non op: closed reduction and application of a sling and harness to maintain reduction of the clavicle.
Short term sling and early range of motion

Operative treatment

Primary AC joint fixation
Primary CC ligament fixation
Excision of the distal clavicle
Dynamic muscle transfers

Acute Surgical Treatment:

For the throwing athlete, the overhead worker, must repair due to risk of reinjury
For Type IV, V and VI injuries

=> Coracoid process transfer to distal transfer (dynamic muscle transfer)
=> Primary AC joint fixation
=>Primary coracoclavicular fixation
=>Distal clavicle excision with CC ligament reconstruction.


Weaver Dunn Procedure

Distal clavicle is excised
The CA ligament is transferred to the distal clavicle
The CC ligaments are repaired and/or augmented with a coracoclavicular screw or suture
Repair of deltotrapezial fascia



Late Surgical Treatment of AC Injury

If pain weakness and deformity persists. It includes reduction of the AC joint and repair of AC and CC ligaments
Resection of distal clavicle and reconstruction of the CC ligaments.