Acromioclavicular Joint Dysfunction

What is Acromioclavicular Joint Dysfunction?

The joint is formed by the connection of the tip of the lateral (outside) clavicle and the acromion which is part of the front of the scapula (shoulder blade). The joint stays in place due to ligaments connecting the two bones. The joint provides support and stability to the shoulder whilst allowing for movements. Irritation of the joint, the ligaments, the joint capsule, the bursa or the muscles surrounding it can refer to pain in the anterior shoulder (front part of the shoulder). Diagnosing AC joint dysfunction will require some specific orthopedic provocative tests and in certain occasions some imaging such as ultrasound, X-ray or MRI. An early and accurate diagnosis can help with the overall management plan and speed up the process of recovery.

Depending on the mechanism and background giving rise to the AC joint dysfunction, signs and symptoms may vary.

Common signs and symptoms can be:

• Localized pain on the anterior shoulder
• Radiating pain from the anterior shoulder to the rest of the arm
• Pain worse when moving the arm across the body or doing overhead movements
• Difficulty reaching behind the back
• Difficulty lifting heavy objects with the affected arm
• Difficulty lying or sleeping on the affected shoulder
• Mild swelling, tender to touch and crepitus (clicking, popping, snapping, crunshing) when moving the shoulder

In cases of severe damage following trauma such as a fall or collision the collarbone (clavicle) might be elevated or protruding from the shoulder whilst causing excruciating pain.

AC joint dysfunction accounts for close to 40% of all shoulder injuries following sports injuries through collisions or road traffic and cycling accidents (Kiel J. & Kaiser K., 2021). AC joint injuries are more often seen in individuals under 30 years old, in males more than females and in athletes competing in contact sports more than normal athletes and non athletic individuals.

AC joint dysfunction can be diagnosed using a variety of methods always starting from the case history exploring the background of the presentation and the potential of injury or trauma. Once any serious pathologies or urgency of referral is ruled out a physical examination will be performed by the practitioner. Palpation of the painful area and the surrounding tissues will be performed followed by active and passive movements of the shoulder. The final step of the physical examination involves provocative and resistance tests aiming to reproduce the symptoms experienced. If during the active or passive movements there is enough pain, provocative and resistance tests might not be used to avoid further irritation of the area.

In cases where there has been a traumatic injury and there is evidence of possible fracture, dislocation or severe soft tissue (ligaments, tendons, muscles) damage, imaging will be used after a short case history. X-ray is the most common scan to diagnose fractures, whilst an MRI will be used in dislocation injuries to diagnose the severity of the ligamentous and muscular damage. MRI can be also used in cases of AC osteoarthritis to diagnose the stage of the condition.

AC joint dysfunction will be treated accordingly to the type of injury, the level of progression and the current symptoms. Some treatment options will be listed below.

• Surgery: This will only be used if the clavicle (collarbone) has been fractured or if the AC joint has been dislocated to a grade 3 tear, meaning that most ligaments are torn. Reconstruction will be needed in both cases and often a metal plate and screws might be inserted into the clavicle.
• Keyhole surgery: This will often be performed if the dislocation is grade 2 or below and there is only a partial tear of the ligaments that can be more easily reconstructed.
• Osteopathy: Osteopathy uses a number of different techniques such as mobilization, soft tissue techniques, muscle energy techniques and others to improve the quality and quantity of the movement of the joint whilst decreasing the pain levels and speeding up the healing process. Osteopaths will also prescribe a few stretching and strengthening exercises when relevant to continue with the healing and protect the joint from future incidence.
• Physiotherapy: Physiotherapy uses some hands on techniques but focuses more on exercises that help relieve the joint from any stretches whilst making it more mobile and strong.
• Kinesiology Tape: This is often used by osteopaths and physiotherapists if relevant at the end of the treatment to provide a bit of an extra support and aid with the healing process of the tissues.

Depending on the mechanism of injury or the stage of the condition when dealing with AC joint sprain or dislocation or AC osteoarthritis, recovery time may vary from a few days to several weeks or it may never return to full function if the damage that has been done is permanent or progressive. Early diagnosis, treatment and rehabilitation can improve the progression of the damage in the long term and prevent further complications.

AC joint osteoarthritis arising from abnormal joint mechanics adding excess forces to the joint can be prevented if the biomechanical problem is picked up early by an osteopath or physiotherapist and the right advice and treatment is given.

AC joint osteoarthritis can also be seen earlier if the joint has been injured, sprained or dislocated. Preventing AC joint dysfunction in this case is more difficult however, if once again your osteopath or physiotherapist gives you the right advice and rehabilitation exercises the chances of reducing the severity or even delaying the onset or progression can be reduced.

Finally AC joint dysfunction arising from traumatic events or injuries cannot be prevented. However, the final outcome can be better if the whole shoulder complex has a certain level of strength which can be achieved by the right strengthening and stretching.

Depending on the severity of the injury or pathology and the progression of the AC joint dysfunction, exercises will vary. Exercises will mostly involve strengthening and stretching, aiming to achieve better mobility and stability of the joint and minimizing the risk of future injury or flare up.

Strengthening Exercises

Rotator cuff: Movements performed will be internal & external rotation and abduction of the shoulder. Start by anchoring a resistance band at elbow height. Keep your elbow by your side and slowly against the resistance externally rotate your shoulder. For internal rotation perform the same movement in the opposite direction. For shoulder abduction, anchor the resistance band below your feet whilst sitting or standing. Keep your elbows slightly bent and then raise both shoulders onto the side not going past 100 degrees of abduction. Return to the starting position slowly. For all the above exercises perform 3 sets of 12-15 slow repetitions.
Face pull with external rotation: Start by anchoring a resistance band at eye level. Hold onto both ends and slowly pull towards your face whilst squeezing your shoulders blades together. At the end of the movement slowly externally rotate your shoulders whilst keeping your shoulders blades together. Repeat for 3 sets of 12-15 reps.
Push press & Strict press: These two variations can be used in the later stages of the rehabilitation to build up strength and mobility of the joint. Perform with dumbbells or barbell by resting weight onto your collarbones and then driving the weight overhead with either a small push from the legs or with locked legs.

Mobility Exercises

Theraband or stick assisted mobility: Perform movements to warm up the shoulders and AC joint by using a band or stick between your hands, going overhead and behind the back, engaging into different angles.
Pectoral Stretch: This stretch will achieve good mobility of the shoulder by reducing the protraction of the shoulders whilst encouraging freer movement. Perform by placing your forearm flat on a wall with your elbow bent at 90 degrees. Keeping your back straight slowly lean forward until the stretch is felt. Hold the position between 30-60 seconds.
Thoracic mobility: Perform rotational and extension movements of the upper back to improve mobility and open up the thorax, which will improve shoulder and AC joint mobility.

Following a traumatic injury of the shoulder and AC joint and with the suspicion of possible dislocation or fracture of the clavicle (collarbone) it is important to go straight to A&E in order to access and treat accordingly. Delaying by a few hours would not affect the overall outcome however pain levels and the chances of causing more damage to the already injured area could increase.

If the AC joint pain has a gradual onset without any recent trauma to the area it is better to see a physical therapist in order to determine the cause of the problem. The examination will be thorough and if the practitioner cannot find the exact causation or is suspecting something more sinister, they will refer you to your GP with a referral letter if needed and the appropriate course of action will be taken.

Kiel, J. and Kaiser, K., 2018. Acromioclavicular joint injury.

Sirin, E., Aydin, N. and Mert Topkar, O., 2018. Acromioclavicular joint injuries: diagnosis, classification and ligamentoplasty procedures. EFORT open reviews, 3(7), pp.426-433.