Shoulder Acromioclavicular Joint (ACJ) Sprain
What is it?
The AC Joint or acromioclavicular joint is a small joint between the acromium of the shoulder blade and the collarbone. It forms an important link between the arm and the skeleton and plays an important role when elevating the arm.
The AC Joint has a capsule and small AC Joint ligaments, which provide stability. Although the AC Joint ligaments are relatively weak, there are also two much stronger ligaments that attach the clavicle to a different point on the shoulder blade called the coracoid. These ligaments are termed the conoid and trapezoid ligaments and are collectively known as the coracoclavicular ligaments. They hold the clavicle in place and prevent it from being displaced upward.
Grade 1 AC Joint Injury – Minor damage of the ACJ ligaments without damage to the coracoclavicular ligaments. There is no displacement of the clavicle in a grade 1 AC Joint injury.
Grade 2 AC Joint Injury – Damage of the AC Joint ligaments as well as the coracoclavicular ligaments. There may be slight upward displacement of the clavicle in a grade 2 AC Joint injury.
Grade 3 AC Joint Injury – Rupture to the AC Joint ligaments and the coracoclavicular ligaments. There is significant upward translation of the clavicle leading to a step deformity in a grade 3 AC Joint injury.
Grade 4 and above - AC Joint Injuries can be considered variations of a grade 3 AC Joint injury and usually require surgery.
Mechanism of Injury
Traumatic AC Joint injuries are most commonly caused by a direct impact to the shoulder but can also occur due to a fall on an outstretched hand, cyclists after falls from their bike and in contact sports such as rugby and football.
Acute AC Joint Injury Symptoms:
AC Joint injuries are traumatic in nature resulting in significant pain at the point of injury. The pain is localised but may extend upward into the neck or down into the front of the shoulder. Depending of the severity of the AC Joint injury, there may be swelling and/or a bump at the end of the clavicle. There is usually an inability to raise the arm above shoulder height due to pain.
Semi-Acute AC Joint Injury Symptoms:
Pain on palpation of the AC Joint
Pain with elevation of the arm above shoulder height, sometimes only at the end of range
Pain with reaching across the body and behind the body
Pain and weakness when pushing weight and carrying significant weight, eg. push ups, bench press, shoulder press, chin ups.
Common Management Techniques
Physiotherapy Treatment for AC Joint Injuries:
Grade 1 AC Joint Injury Treatment:
Sling or taping for comfort only
Rest from aggravating activities
Dry needling
Massage to ease muscle tension and pain
Strengthening exercises
Graduated return to sport plan
Grade 2 and 3 AC Joint Injury Treatment:
Sling for comfort and to allow soft tissue inflammation to settle
Discussion regarding the benefits and risks of surgery. Please note that surgery must be performed in the first couple of weeks to ensure the best results (see below).
Rest from aggravating activities
Dry needling or massage to ease muscle tension and pain
Gradually progressed strengthening exercises
Graduated return to sport plan
Medical Treatment for AC Joint Injuries:
Anti inflammatory medication
Cortisone injection into the AC Joint if inflammation persists
Surgical Treatment for AC Joint Injuries:
Surgery involves realignment of the clavicle with the acromium. This is achieved with the use of a plate or sutures. The plate provides significant strength and support but it restricts joint movement and must be removed after a short period of time. The sutures are more vulnerable to failure but don’t restrict range of motion and don’t need to be removed.
Prognosis
For some people a course of physiotherapy for 6 weeks may be suitable, for other it may be ongoing. Some patients who do not respond to conservative management may need to go on to having surgery or the use of injection to aid in management of the disorder combined with exercise therapy.