Acromioclavicular Joint Sprain

An acromioclavicular (AC) joint sprain is a shoulder injury involving damage to the ligaments that support the joint between the collarbone (clavicle) and the shoulder blade (acromion). It most commonly occurs following a direct impact to the top of the shoulder, such as a fall onto the shoulder or a collision during contact sport.

AC joint injuries are graded based on the severity of ligament damage:

• Grade I – mild sprain with minimal pain and no visible joint displacement
   
• Grade II – partial ligament tear with moderate pain and some joint prominence
   
• Grade III – complete ligament rupture with clear elevation of the collarbone
   
• Grades IV–VI – more severe injuries with significant displacement (less common and often require specialist review)
   

Common symptoms include pain at the top of the shoulder, swelling, tenderness, reduced shoulder movement, and pain with lifting the arm or across-body movements. In higher-grade injuries, a visible “bump” over the shoulder may be present.

Physiotherapy plays an important role in recovery and focuses on:

• Reducing pain and inflammation
   
• Restoring shoulder range of motion and strength
   
• Improving scapular and shoulder control
   
• Supporting a safe and confident return to work, sport, or daily activity