If you have ever suffered from an AC joint injury, you know that the road to recovery can be lengthy. Physiotherapy is often highly recommended for these injuries.
Physiotherapy can help with many issues, such as reducing pain and inflammation or increasing your range of motion and strength. It also has the added benefit of speeding up the healing process while avoiding further injury.
What is the AC joint?
The AC joint is a plane synovial joint formed between the acromion of the scapula (shoulder blade) and the distal end of the clavicle (collarbone) on top of the shoulder.
The joint is stabilised by the acromioclavicular (AC) ligaments, coracoclavicular (CC) ligaments and the coracoacromial (CA) ligament. This joint is small but contributes to achieving a full shoulder range of motion.
Prevalence AC injuries are common in sports such as football, rugby league and rugby union. They may account for up to 40% of all shoulder injuries and nearly 10% of all injuries in collision sports.
Common causes of AC joint injury
The AC joint’s two bones are held together by four ligaments. These ligaments are stressed when an AC joint injury occurs. This stress causes joint separation to some extent. There are two types of AC joint injuries: overuse and traumatic injuries.
Overuse AC joint injury
This type of injury develops over time due to repeated and excessive stress on the joint. As a result, an overuse injury occurs, which can lead to significant cartilage wear and arthritis. Overuse of the AC joint is most common in people who perform repetitive tasks.
- Lifting heavy weights (bench and military presses).
- Jobs requiring physical labour with arms stretched over the head.
Traumatic AC joint injury
When the joint is disrupted, this type of injury occurs. The ligaments that connect the two bones of the joint become overly stretched. This is known as shoulder separation. Traumatic AC joint injuries can range in severity from mild to severe.
People who fall and land on the outside of the shoulder or hand are more likely to sustain traumatic AC joint injuries.
- A worker falls from a ladder.
- A cyclist crashes.
- A football player who has been tackled.
Common symptoms of an AC joint injury
You may experience the following symptoms if you have an AC joint injury:
- There is a noticeable bump above the shoulder.
- Shoulder pain and swelling in general.
- When lying on the affected side, there is pain.
- Loss of shoulder range of motion.
- A decline in shoulder strength.
- A “popping” sound or the sensation your shoulder “catches” when you move.
- The AC joint is swollen and tender.
- Discomfort from daily activities that put a strain on the AC joint. Some examples are lifting objects overhead, reaching across your body, or carrying heavy objects at your side.
AC joint injury diagnosis
Diagnosis is made on several features:
- Mechanism of injury.
- Step deformity (visible bump on top of the shoulder – see photo below). The bigger the step deformity generally means a higher–grade injury.
- Tenderness on palpation over the AC joint.
- Pain with overhead and horizontal adduction (crossing the arm over the body). This movement compresses the AC joint.
It is essential to see a healthcare professional to rule out other possible injuries. Some other vital things to rule out in an acute shoulder injury include:
- Fractures – particularly to the scapula, clavicle & proximal humerus.
- Rotator cuff tears.
- Neurovascular damage (nerves and blood vessels).
- Glenohumeral joint instability.
- Glenoid labrum tears.
Grades of AC joint injury
Grades of AC joint injury are based on the degree of joint separation – grading is based on the Rockwood classification system (see photo below)
- Grades 1-2 AC joint injuries involve only minor damage to the ligaments, stabilising the joint. These injuries are managed conservatively (with no surgery) with physical rehabilitation.
- Grade 3 injuries involve completely separating the ligaments and stabilising the AC joint. These can be managed either conservatively or surgically. The decision to undertake surgical management is determined by a range of factors, including your age, current level of function and goals.
- Grade 4-6 injuries are managed surgically due to the more significant degree of separation between the clavicle and acromion. These injuries require surgical intervention to stabilise the joint, followed by a comprehensive rehabilitation program. These high-grade injuries are not common, but these injuries can cause ongoing shoulder pain and instability without surgery.
How long does it take for a strained AC joint to heal?
Rehabilitation timeframes will depend on the severity of the AC joint injury. Depending on the extent of your injury, healing may take anywhere from four to six weeks. Grade I injuries have a low chance of being reinjured. However, Grade II injuries are more painful and cause more swelling than Grade I.
All injuries will progress through a series of phases which will involve:
- Reducing pain and swelling
- Increasing muscular control & endurance
- Increasing muscle strength
- Re-integration into sport-specific skills
Final thoughts on Physio For AC Joint Injuries
Physiotherapists are skilled in detecting and treating AC joint injuries, often without surgery. If you’re experiencing any pain or discomfort in your shoulder, it’s best to consult with one of our physiotherapists as soon as possible.
Not only will they be able to provide relief from your symptoms, but they can also help you prevent future injuries from occurring.