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Acromioclavicular joint (ACJ) injuries are common.  The minor sprains are treated with tablets, physiotherapy and rest.  The more severe types need surgery.  The most common type is grade 3, which becomes less prominent when the shoulders are shrugged where as type 4 & 5 get worse when shoulders are shrugged.  The treatment of type 3 is controversial – surgery means more time in a sling, and the result possibly no better at one year.


This type 4 injury has the outer clavicle just under the skin, and more prominent with shrugging.

On XR, the ACJ is widely displaced, the more common type 3 has the joint almost touching.

This injury has be repaired using a modified Ziploop – the joint is reduced and held in place with a temporary wire whilst a drill hole is made from clavicle into the corocoid (yellow arrow) and the stitch positioned and tightened, and the wire removed. This knotless technology is then cut flush, so there is barely a bump on the top of the clavicle.


A schematic diagram of the stitch through both bones with a metal button on top of the clavicle and under the corocoid. Four to six weeks of using a sling is required, then modest activities up to six months before full activities are permitted.

Classification of ACJ injuries (Rockwood 1998)
1. Sprain of AC ligaments
2. Rupture of AC ligaments and partial rupture CA (coracoacromial) ligament
3. Complete rupture of AC & CA ligament, 100% displacement.
4. AC & CA ligaments and deltotrapezial fascia perforated by clavicle backwards
5. AC & CA ligaments and deltotrapezial fascia perforated by clavicle upwards (>25mm)
6. Rare – ligaments ruptured and clavicle under corocoid!

​- Mr David Mitchell