Exploring AC Joint Separation: Causes and Treatment Methods

AC joint separation: an introduction

What is an AC joint separation?

An AC joint separation, also known as an acromioclavicular joint injury, occurs when the joint between the collarbone and the shoulder blade is damaged or completely separated. This can be caused by a sudden force or by chronic strain. The AC joint plays an important role in the mobility and stability of the shoulder.

Grades of injury:

• Grade I – slight stretching of the ligaments
• Grade II – partial separation, ligaments are torn
• Grade III – complete separation, both ligaments are torn
• Grades IV to VI – rare and severe forms of the injury, often with additional damage to muscles and ligaments

The most common causes of AC joint separation

AC joint separations usually result from a direct impact on the shoulder. These injuries are typically found in sports and activities that involve falls and collisions.

Common causes:

• Sports injuries: contact and team sports such as football, rugby or handball frequently lead to AC joint separations through collisions or falls.
• Accidents: cycling or motorcycling accidents, but also falls from a horse or while skiing, can damage the AC joint.
• Accidents at work: activities that involve repeated overhead work can increase the risk of an AC joint separation.

Further information on injuries and symptoms can be found on our pages about bone fractures and shoulder pain.

Understanding the causes and mechanisms of these injuries can help in developing appropriate prevention and treatment strategies. Read more about the various diagnostic procedures in the section on symptoms and diagnosis.

Symptoms and diagnosis

Typical symptoms of an AC joint separation

An AC joint separation is often associated with particular symptoms that point to the injury. The most common signs of an AC joint separation include:

• Severe pain in the shoulder area
• Swelling and bruising around the collarbone
• Restricted freedom of movement in the shoulder
• Visible deformity or protrusion of the collarbone
• Muscle weakness in the affected arm

Frequency of the symptoms in patients:

• Pain: 100 per cent
• Swelling: 85 per cent
• Restricted movement: 75 per cent
• Deformity: 60 per cent
• Muscle weakness: 45 per cent

These symptoms can vary according to the severity of the injury. An accurate diagnosis is needed in order to determine the best treatment plan. You can find further information on shoulder pain on our dedicated page.

Diagnostic procedures for AC joint separation

Diagnosing an AC joint separation involves several steps, including both clinical examination and imaging.

• Clinical examination: the doctor carries out a physical examination to assess the mobility of the shoulder and where the pain is located. The following tests are used:
  • Visual inspection for swelling and deformity
  • Palpation of the shoulder to identify the exact point of pain
  • Assessment of shoulder mobility
• Imaging:
  • X-ray: X-ray images help to identify bone fractures and the exact position of the collarbone.
  • MRI (magnetic resonance imaging): an MRI can provide more detailed images of soft tissue and ligaments and is helpful in assessing more extensive damage.
  • Ultrasound: ultrasound images can be used to identify fluid build-up and soft tissue injuries.

Purpose of each procedure:

• X-ray – detection of bone fractures and the position of the collarbone
• MRI – detailed images of soft tissue and ligaments
• Ultrasound – detection of fluid build-up and soft tissue damage

The right diagnosis makes it easier to choose a suitable treatment strategy, whether conservative treatment or surgery. Further information on specific surgical procedures can be found under shoulder surgery.

With these diagnostic methods, an orthopaedic specialist can determine the best treatment for an AC joint separation and guide the patient on the road to recovery.

Treatment methods

The treatment of an AC joint separation can involve both conservative and surgical approaches. The choice of the right method depends on the severity of the injury as well as the individual needs and activities of the patient.

Conservative treatment

Conservative treatment is often preferred for less severe AC joint separations, or for patients who wish to avoid surgery. Common conservative methods include:

• Immobilising the shoulder: a splint or bandage can be used to immobilise the shoulder and so promote healing.
• Pain management: the use of painkillers and anti-inflammatory medication helps to reduce pain and swelling.
• Physiotherapy: a specific rehabilitation programme aimed at improving mobility and strengthening the shoulder. Further information can be found in our article on physiotherapy.

Purpose of each conservative method:

• Splint or bandage – immobilisation
• Painkillers – pain reduction
• Physiotherapy – mobility and strength

Surgery for AC joint separation

In more severe cases, or when conservative treatment does not bring the desired result, surgery may be necessary. There are various surgical techniques that are used depending on the type and grade of the injury.

• Stabilisation of the collarbone at the shoulder: screws or plates are used to hold the collarbone in position.
• Tendon reconstruction: with this method, torn tendons are reattached to their original position.
• Arthroscopic procedures: these minimally invasive operations allow a fast recovery and are often used for less complex injuries.

Purpose of each surgical method:

• Stabilisation of the collarbone – restoring stability
• Tendon reconstruction – reattaching the tendon
• Arthroscopic procedures – minimally invasive repair

Further information on surgical procedures can be found in our articles on shoulder surgery and tendon reconstruction.

The choice between conservative and surgical treatment should be made in consultation with a specialist, who can suggest the best method based on the patient’s specific situation and requirements. Further information and treatment options can also be found in our articles on shoulder pain and sports injuries.

The rehabilitation process

The rehabilitation process after an AC joint separation is crucial for a successful recovery. The focus is on restoring mobility and strengthening the muscles.

Physiotherapy after an AC joint separation

Physiotherapy plays an essential role in the rehabilitation of patients with an AC joint separation. Individually tailored physiotherapy measures are designed to improve the mobility of the shoulder and reduce pain. A typical treatment plan can include passive movement exercises and specific mobilisation techniques.

• Early phase (1–3 weeks) – aims: pain relief, reduction of inflammation; measures: cold therapy, passive movement exercises
• Middle phase (4–6 weeks) – aims: improving mobility; measures: gentle mobilisation, light stretching exercises
• Late phase (from week 7) – aims: building strength, restoring function; measures: resistance exercises, targeted muscle strengthening

Recommended exercises for strengthening the shoulder muscles

Targeted exercises are needed to stabilise and strengthen the shoulder after an AC joint separation. These exercises are intended to strengthen the muscles and support the stability of the shoulder joint.

• Pendulum exercise
  • Loosening and gentle movement of the shoulder.
  • Forward and backward movements as well as circular movements with the arm hanging down.
• Isometric exercises
  • Tensing the shoulder and chest muscles without moving through a range of motion.
  • Pushing against a wall or an immovable object.
• Resistance band exercise
  • Strengthening the rotator cuff.
  • Pulling a resistance band in different directions.
• Scapula push-up
  • Increasing the stability of the shoulder blades.
  • Slow push-ups with the focus on the shoulder blade area.

For detailed information on individual exercises and further treatment methods, read our articles on shoulder pain and shoulder arthroscopy.

By combining physiotherapy with suitable strengthening exercises in a targeted way, the function of the shoulder can be effectively restored and long-term damage avoided.

Prevention and long-term care

Measures to avoid AC joint separation

Preventing AC joint separations is essential in order to avoid injuries and long-term damage. Here are some proven measures:

• Strengthening the shoulder muscles: regular exercises to strengthen the shoulder and back muscles can reduce the risk of an AC joint separation. See our section on recommended exercises for strengthening the shoulder muscles for specific training suggestions.
• Correct technique in sport: learning and applying the right techniques during sporting activities, especially in contact sports, can prevent accidents.
• Wearing protective clothing: wearing suitable protection, such as shoulder pads, can help to prevent damage in falls or collisions.
• Ergonomic workplace design: setting up an ergonomically correct workplace can help to avoid poor posture and overloading of the shoulder.

Preventive measures at a glance:

• Muscle strengthening – exercises to strengthen the shoulder and back muscles
• Correct technique – applying proper sporting technique
• Protective clothing – use of shoulder pads
• Ergonomics – adapting the workplace

Long-term care and prevention for the shoulder

After an AC joint separation, it is crucial to look after the health of the shoulder in the long term. Here are some tips on care and prevention:

• Regular physiotherapy: ongoing physiotherapy treatment helps to restore the function and mobility of the shoulder. Further information can be found in our section on physiotherapy after an AC joint separation.
• Continued training: even after rehabilitation, exercises to strengthen and stabilise the shoulder should be carried out regularly.
• Avoiding overload: excessive loading and repetitive movements should be avoided so as not to damage the shoulder again.
• Regular medical check-ups: regular examinations with an orthopaedic specialist or doctor can help to identify and treat problems at an early stage.

For more detailed guidance on exercises and techniques to avoid shoulder problems, visit our articles on shoulder pain and shoulder osteoarthritis.

With preventive measures and consistent long-term care, the risk of a repeat injury can be reduced and the health of the shoulder safeguarded over the long term.