Acromial Clavicular (AC) Sprain
The AC joint is a joint between the clavicle (collar bone) and the acromion (roof of the shouder). It forms an important role in securing the shoulder girdle, connecting the sternum to the shoulder and scapula (shoulder blade).
The AC joint has 3 ligaments that hold it together, keeping the joint between the acromion and clavicle stable. When there is an impact on the tip of the shoulder, these ligaments get stretched and can tear. It is common amongst cyclists, who fall onto the tip of the shoulder, and sports where there is an impact on the point of the shoulder.
There are 3 key indicators that the AC joint is sprained:
1. The mechanism of injury – falling on the tip of the shoulder
2. Tenderness over the AC joint
3. Horizontal adduction is painful (taking the arm across the chest)
The symptoms include severe pain, swelling and an inability to move the joint.
Treatment involves firstly, settling the pain and swelling. This may require a sling to rest the joint, if it is more severe. Then movement needs to be gradually restored. Following this, the shoulder and scapular muscles that support the joint need to be strengthened. Rehab has to be pain-sensitive and progressed gradually. A gentle return to sport requires an understanding of the game and the therapist needs to create a programme that eases the athlete back into competition.
Dislocated AC Joint
When an AC joint sprain is more severe, there is a separation between the acromion and the clavicle. This can be seen as a lump over the clavicle, as the arm pulls the acromion downwards. When it is severe, we call this a dislocation.
The severity of the dislocation can vary. It can be classified depending on the extent of ligament damage:
Grade 1 – a sprain without ligament damage
Grade 2 – a partial separation without structural ligament damage
Grade 3 – complete dislocations with extensive ligament damage
With more severe dislocations, surgery may be needed. This sort of operation reconstructs the torn ligaments and stabilises the joint.
The choice between physiotherapy and surgery is not straight forwards. Important factors to consider include the patient’s age, their activity level, and the severity of the dislocation.
At Melbourne Shoulder Therapy, we have established protocols for post-operative rehabilitation following surgery for AC joint surgery.