AC Injury

The Acromioclavicular (AC) Joint is a common site of injury particularly for athletes involved in contact and collision sports or sports / movements that involved throwing.


The AC Joint makes up of the shoulder structure. It is at the point at which the lateral end of the clavicle (collar bone) meets with the part of the scapula (shoulder blade) called the Acromion process. It can be identified by sight and touch as the pointy protrusion near the top, outer edge of the shoulder.

The joint is surrounded by a joint capsule and has additional support provided by the acromioclavicular and coracoclavicular ligaments. The acromioclavicular and coracocla­vicular ligaments are usually the ligaments to be damaged in the most common injuries to the AC JOIN


Risk of Injury

1.AC Injury often occurs as a result of a direct blow to the tip of the shoulder from for example an awkward fall, or impact with another player.

This forces the acromion process downward beneath the clavicle; OR

  1. The AC joint may injure as a result from an upward force to the long axis of the humerus for example a fall which directly impacts on the wrist of a straightened arm. Injury happens most typically when the shoulder is close to the body (adducted) and bent (flexed) position.



Wearing protective strapping to support a previously injured AC joint. Particularly in contact sports

Warming up stretching and cooling down

Participating in fitness programmes to develop strength, balance, coordination and flexibility

Undertaking training prior to completion to ensure readiness to play Gradually increasing the intensity and duration of training

Allow adequate recovery time between workouts OR/ training sessions Wearing the right protective equipment including footwear

Avoiding activities that cause pain. If pain does occur – discontinue immediately and commence RICER (rest, ice, compression, elevation & referral to Physiotherapist



Pain at the end of the collar bone

Pain may feel widespread throughout the shoulder untiI pain resolves following this. This is more specific to the joint itself

Swelling Often occurs.

Depending on the extent of the injury a step- deformity may be visible at this area. There

 is an obvious lump

Pain will be felt on moving the shoulder, especially when trying to raise the arms at shoulder height.



Grade l

 A person with grade l injury of the AC joint will experience tenderness and

discomfort, or experience pain when the Physician or physiotherapist is assessing and moving the jo int.

Grade l sprains involve only partial damage to the joint capsule and AC ligament


Grade 2 – MODERATE:

A Grade 2 injury will involve complete rupture of the acromioclavicular ligaments and partial tearing of the coracoclavicular ligament.

The tearing means the clavicle can move upward, and the bump on the shoulder is greater.

Pain is more severe and movement of the shoulder is restricted.


Grade 3- SEVERE:

A grade 3 injury involves complete rupture of the acromioclavicular and coracoclavicular ligaments

The bump is visible and even more pronounced due to the capsule dislocation



The Immediate treatment of any soft tissue injury consists of RICER (REST, ICE, Compression, Elevation & Referral).

The area should be RICE treated for 48- 72 hours post injury

The aim of this is to reduce swelling and bleeding & damage within the joint. The shoulder should be rested in an elevated position with an ice pack applied for 20 minutes to every 2 hours. (Never apply ICE directly to the skin)

The arm should be in a sling to immobilize and prevent movement NO HARM PROTOCOL: no heat, no alcohol, no running or movement/ activity and NO MASSAGE

Proceed to seek Physiotherapy Treatment.