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See also:
- AC joint separation exercises
- AC joint injuries explained in a minute
- Taping techniques for AC joint injuries
AC Joint Separation
An AC joint separation of AC joint sprain is an injury to the ligament that holds the acromioclavicular joint together. It is usually caused by fall onto an outstretched arm.
Symptoms of AC Joint Injury
Symptoms of an AC joint sprain will include pain right at the end of the collar bone. The pain my be widespread throughout the shoulder initially but later on more localized. Pain will be worse when trying to move the arm above the shoulder. There is often swelling and depending on the extent of the injury a deformity may be seen. This is an obvious lump where the joint has been disrupted and is visible on more severe injuries.
What is the Acromioclavicular Joint?
The AC joint is short for the acromioclavicular joint. Separation of the two bones forming this joint is caused by damage to the ligaments connecting them. It is sometimes also referred to as a shoulder separation injury.
The acromioclavicular joint is formed by the outer end of the clavicle (collar bone) and the acromion process of the scapular (shoulder blade). The acromion is a bony process which protrudes forwards from the upper part of the scapular. This joint forms the highest part of the shoulder. The two bones are attached by the acromioclavicular (AC) ligament. There are several other ligaments which can be of importance in AC joint injuries, including the coracoclavicular (CC) ligament (divided into conoid and trapezoid sections) which joins the clavicle to the coracoid process, another forward protruding part of the scapula, slightly below and to the inside of the acromion.
A third ligament is the coracoacromial ligament which attaches the acromion process to the coracoid process, although it is rarely involved in this type of injury.The most common way of injuring the AC joint is by landing on the shoulder, elbow, or onto an outstretched hand.
AC joint separation grading
AC joint injuries are graded from 1-6 using the Rockwood scale which classifies injuries in relation to the extent of ligament damage and the space between the acromion and clavicle.
- Grade 1 is a simple sprain to the AC joint
- Grade 2 involves rupture of the AC ligament
- Grade 3 rupture of both AC and CC ligaments which often results in a superior displacement.
From this point onwards the scale and grade of injury depends on the degree of displacement of the clavicle.
- Grade 4 involves posterior displacement
- Grade 5 superior displacement, to a greater degree than grade 3, with an increase in coracoclavicular space by 3-5 times the norm. A step deformity may be apparent with grade 3, 4 & 5 injuries.
- Grade 6 involves full rupture of both AC and CC ligaments with the clavicle being displaced inferiorly.
AC joint separation treatment
What can the athlete do?
- Rest and apply ice (cold therapy) in the early stage
- Immobilise the shoulder in a sling to ease pain by taking the weight of the arm
- See a Sports Injury Specialist or Doctor
What can a Sports Injury Specialist or Doctor do?
- Apply an AC joint separation taping which fixes and supports the joint into the correct position to assist with healing. You may need to be taped for 2-3 weeks
- Apply ultrasound for minor injuries, or TENS for pain relief in more severe cases
- Prescribe Anti-inflammatory (such as ibuprofen) medication to reduce pain and inflammation.
- Advise on AC joint sepration exercises
- Surgery if required (usually grades 4-6)
WARNING - If this injury is neglected and allowed to heal out of place this could increase the wear and tear on your joint causing you problems in the future
