Overview on AC joint injury

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An AC joint injury or shoulder separation involves damage to the ligaments that support the acromioclavicular joint is overly stretched.

The acromioclavicular joint is positioned on top of the shoulder amidst the clavicle and scapula. The joint is vital in allowing overhead and across body motions of the arm. The severity of damage to the joint varies from a minor strain of one or several adjacent ligaments to full tears and deformity.

Pain or achiness on the upper part of the shoulder that is worsened by overhead and across body motions as well as heavy lifting.

What are the causes?

A direct blow or strike can damage the AC joint if an individual collides with a solid surface or object such as a fall from a bicycle or during football where the shoulder hits the ground.

The joint might also be damaged indirectly if an individual fall on an extended arm. The force is transmitted up the arm which leads to the separation of the acromion and clavicle. In addition, the ligaments are overly stretched and injured in the process.

What are the indications?

  • Pain or discomfort on the upper part of the shoulder that is worsened by overhead and across body motions as well as heavy lifting
  • Loss or diminished shoulder movement
  • Swelling and bruising
  • In some cases, a hard, evident lump might form on the top part of the shoulder which indicates displacement of the collarbone.

Management of AC joint injury

Generally, an individual with AC joint injury starts to feel better in just a few days or a week after the injury. Nevertheless, complete healing will take at least 6 weeks. During this period, it is vital to protect the ligaments from overly stretching the immature scar tissue. It might be beneficial to utilize a sling, taping or a shoulder brace which relieves the load from the AC joint.

The objective of treatment includes the following:

  • Lower the inflammation and pain
  • Strengthening of the shoulder
  • Normalize the range of motion of the joint
  • Improve the shoulder alignment
  • Correct the technique and function especially with lifting or overhead activities

In severe cases, surgery might be carried out to secure the AC joint or fix the injured ligaments adjacent the joint.

Rehabilitation after surgery is vital which aims on restoring full shoulder movement, strength, endurance and power. In addition, proprioception and re-training is also required.

Quick Note / Disclaimer

The material posted on this page on AC joint injury is for learning and educational purposes only. To learn to recognize and manage this type of joint injury, register for a first aid and CPR course with Mississauga First Aid.

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