Waverley Park Physiotherapy Centre Common Injury Series AC Joint


Article 3: Shoulder Injuries in Sport – AC Joint Injuries

The shoulder is one of the most mobile joint in the human body.  It’s ball and socket formation with shallow socket provides almost a complete half spherical range of motion or more. However with mobility and freedom comes weakness and vulnerability.

The shoulder is held in place by a complex formation of ligaments, muscles and tendons which function to provide shoulder strength, movement and some stability. However the shoulder is still a very easily and commonly injured joint.

AC Joint Injuries: The AC Joint is the shoulder in the front of the shoulder where the collar bone joins in. This joint is a pivot point for the shoulder but mostly acts as a stabilizing rod for the rest of the shoulder to operate around. It’s movement is limited, to the point that one can live with a complete dislocation of the AC joint with minimal loss of function.  However again this is dependent on how the injury is treated.

The AJ Joint is usually injured in one of 3 ways:

  • Direct impact during a tackle the collar bone or the shoulder is forced backwards and the joint is injured.
  • Falling onto the elbow, either forward or to the side and landing in a ‘propped’ position.   The arm is forced upwards through the shaft of the upper arm and the AC joint is injured.
  • Falling directly onto the shoulder, usually during a tumble or fall head down, the point of the shoulder strikes the ground and is forced towards the feet, and the collar bone and bodyweight continues groundward.

AC Joint injuries are classified into 3 levels.

  • Grade 1 – Small sprain to the joint, pain, usually minimal swelling, and usually joint stiffness and limited movement. This injury usually recovers fully within 6 weeks and with strapping return to sport can be possible in 2-3 weeks
  • Grade 2 – partially torn ligaments or completely torn ligaments but not all of them.   In this grade there is visible swelling as well as a visible ‘step deformity’ where the end of the collar bone is visibly ‘popped up’.  This injury can take 4-12 weeks to heal depending on the severity of injury and can prevent a player from returning to sport for up to 6 months for contact sport.
  • Grade 3 – This is a complete rupture of the ligaments holding the joint together, and thus a dislocation of the joint. The end of the collar bone will sit wildly high and completely out of touch with the rest of the shoulder. However even such colossal injuries are not necessarily a surgical problem. Depending on the required function, a Grade 3 AC injury may often not be surgically fixed unless, for example, the patient is a heavy laborer/lifter, or a contact sport athlete.

All of these Grades of AC Joint Injury will require extensive physiotherapy in order to recover fully in the case of a Grade 1, or as fully as is possible in the case of Grade 2/3

If you have a AC Joint shoulder injury; seek physiotherapy. Treatment can be the difference between weeks of lingering pain, or between re-injury and full recovery.

About the Author: As a physiotherapist, Victorian State Touch Rugby representative and regular weekend sports warrior, Jordan Coleman has extensive experience in the treatment of common sports related injuries.

For consultation with Jordan Coleman at Waverley Park Physiotherapy Centre call on 97950668