Acromioclavicular Joint Injury

What is an acromioclavicular joint injury?

  • Acromioclavicular joint injuries involve damage to the joint between the collar bone and the shoulder blade. Typically, this follows a fall on an outstretched hand, elbow, and direct impact onto the tip of the shoulder .

How common is an acromioclavicular joint injury?

  • Acromioclavicular joint injuries involve damage to the joint between the collar bone and the shoulder blade.
  • Typically, this follows a fall on an outstretched hand, elbow, and direct impact onto the tip of the shoulder.
  • Acromioclavicular joint injuries make up approximately 9% of all shoulder injuries (3, 6).
  •  This is less than 1% of all adult injuries.

Should I worry?

  • No.
  • Most acromioclavicular joint injuries are treated with physiotherapy and will make a full recovery.
  • There are different grades of the injuries from type I – VI.
  • Lower grade injuries are treated with immobilisation for a few weeks followed by exercise rehabilitation.
  • Higher grade injuries may require surgery (6). However, these more serious cases are rare.

Who is most likely to suffer from an acromioclavicular joint injury?

  • Athletes account for 40% of acromioclavicular joint injuries.
  • Athletes from contact and high-speed sports such as hockey, rugby, skiing, football, snowboarding and cycling (4).
  • It is seen 5 times more in men than in women.
  • It most commonly occurs in people between the ages of 20-30 (5).

What are the common symptoms?

  • Pain on the top of the shoulder which may radiate into the neck and upper arm.
  • Symptoms aggravated by heavy lifting, overhead and across body movements.
  • Swelling/bruising.
  • Loss of shoulder movement.
  • A visible deformity can often be seen on the tip of the shoulder (3), called a ‘step deformity’ as it can look like a step. Do not worry as this is common with this injury and does not indicate a serious problem.

What can I do?

  • Advice from a qualified health professional would help to determine the extent of injury and employ the best management strategy.
  • Sling immobilisation is commonly recommended for type I – III injuries (7).
  • Once the pain has reduced, a progressive exercise programme will help to ensure you return to normal shoulder function.

How long will it take to recover?

  • This will depend upon several factors including existing injuries/problems, severity of injury, adherence to rehabilitation, etc.
  • In a type I injury, returning to normal activity should take 2-4 weeks (7).
  • In a type II, typically 4-6 weeks (7).
  • In a type III, typically 6-12 weeks (7).
  • It should be noted that most people will make a full recovery from the injury despite the fact that the visual (step) deformity may often remain.

1. Introduction

The acromioclavicular (AC) joint – which may be described as the ‘tip’ of the shoulder – is formed by the outside end of the collar bone (clavicle) and part of the shoulder blade known as the acromion. This joint assists with movement of the shoulder blade on the chest and maximises shoulder range of movement and stability. Like all synovial joints, it has a joint capsule and ligaments (acromioclavicular, coracoacromial and coracoclavicular) which provide stability.

Injury to this joint almost always occurs as a result of trauma to the shoulder. In the process of the injury, the collar bone will lift up relative to the acromion. This will cause strain or tearing of these ligaments which is often what causes the pain.


2. Signs & Symptoms

3. Causes

  • Fall onto an outstretched hand or elbow.
  • A direct blow or fall onto the point of the shoulder.
  • A road traffic accident.
  • Acromioclavicular joint injuries are commonly seen in contact sports such as football, rugby, hockey, cycling, skiing/snowboarding and road traffic accidents (4).

4. Risk Factors

This is not an exhaustive list however these factors could increase the likelihood of someone sustaining an acromioclavicular joint injury. It does not mean everyone with these risk factors will develop symptoms.


5. Prevalence

Acromioclavicular joint injuries account for approximately 9% of all shoulder injuries (6). This accounts for less than 1% of all adult injuries. The extent of acromioclavicular joint injury can range from a mild ligament sprain to complete ligament tear resulting in ‘separation’ of the acromioclavicular joint or ‘dislocation’ (although this is rare). In athletes, injury of the joint is seen in 40% of shoulder girdle injuries. Grade I and II injuries are far more common, accounting for up to 90% of cases (3).

6. Assessment & Diagnosis

Your musculoskeletal physiotherapist will take a detailed history to understand how the injury occurred and what your symptoms are. Following this, a comprehensive physical assessment will be completed to establish your function and test specific structures to assist with the accurate diagnosis so that the most appropriate and effective treatment can begin straight away.

In cases where the function is relatively well maintained, there are several physical tests that will help establish the grade of the injury – usually I – III. However, in some cases, an X-ray is utilised to assist with grading and to guide ongoing treatment and management.

Your musculoskeletal physiotherapist will work with you to develop a set of individualised goals to help direct your treatment and facilitate optimal recovery with a successful return to normal activity/sporting performance. We value reassessment to ensure you are making progress and to allow adjustments in your treatment to be made.

7. Self-Management

Alongside a referral within 48 hours if deemed appropriate:

  • A sling/brace is advised to immobilise the shoulder; this can be used in tandem with taping to provide the joint with additional support (7). Elevating the shoulder to a comfortable height is also suggested when resting. A sling can be used until symptoms diminish and function returns.
  • For grade I – III injuries, patients typically return to normal function at 2-4, 4-6 and 6-12 weeks respectively (3). Optimal treatment remains uncertain for type III injuries as favourable outcomes have been observed in both conservative and surgical management. For overhead athletes and those with physical jobs that require higher functional demands for the shoulders, surgical intervention is recommended for greater restoration of function and as such, treatment options should be individualised (2, 5, 7).
  • For type IV injuries and upwards, surgery is often indicated to restore normal anatomy and stability through ligament reconstruction (2, 5, 9).
  • Your physio will help explain the injury and what structures are involved so that you can understand your symptoms and help support your own recovery. As you recover, we provide ongoing guidance so that you can effectively return to your normal activities whilst minimising the likelihood of future complications.

8. Rehabilitation

In most cases, rehabilitation will be the main solution to you getting back to full function following this type of injury.

Below are three rehabilitation programmes created by our specialist physiotherapists targeted at addressing acromioclavicular joint injury. In some instances, a one-to-one assessment is appropriate to individually tailor targeted rehabilitation. However, these programmes provide an excellent starting point as well as clearly highlighting exercise progression.

9. Acromioclavicular Joint Injury Rehabilitation Plans

Early Plan

This programme focuses on maintaining range of movement within the shoulder and maintenance of scapular control (9). We suggest you carry this out once a day for approximately 2-4 weeks as pain allows. As with the early programme, some discomfort is to be expected but the pain should not exceed 4/10 on your perceived pain scale whilst completing this exercise programme.

Early Plan - Rating

Intermediate Plan

This is the next progression. More focus is given to progressive upper limb strengthening with closed kinetic exercises towards open chain resistance exercises. As with the early programme, some discomfort is to be expected but, ideally, pain should not exceed 4/10 whilst completing this exercise programme.

Intermediate Plan - Rating

Advanced Plan

This programme is a further progression of exercises to increase the strength and stability of the shoulder. When the full range of motion is achieved alongside comparable strength to the non-affected limb, return to activity can take place (2). Pain should not exceed 4/10 whilst completing this exercise programme.

Advanced Plan - Rating

10. Return to Sport/Normal Life

For patients wanting to achieve a high level of function or return to sport we would encourage a consultation with a musculoskeletal physiotherapist as you will likely require further progression beyond the advanced rehabilitation stage. Before returning to sport, a rehabilitation programme should incorporate plyometric based exercises; this might include things like tossing and catching a plyometric ball, throw overhead side to side and plyometric push ups.

As part of a multi-modal treatment approach, your physio may also use a variety of other pain-relieving treatments to support symptom relief and recovery. Whilst recovering, you might benefit from further assessment to ensure you are making progress and establish appropriate progression of treatment. Ongoing support and advice will allow you to self-manage and prevent future reoccurrence.

11. Other Treatment Options

In severe and traumatic cases, grade IV – VI, there is a high likelihood that surgical intervention will be required as the preferred treatment approach (4). Despite continuous advances in surgical procedures – with up to 160 various techniques described (9) – the gold standard for surgical intervention remains elusive, however, the evidence recommends that each surgeon’s expertise – alongside deliberating the associated benefits and risks – should dictate the procedure used (5, 9).

Surgery will restore normal anatomy and stability to the joint. Post-surgical management is very similar to that of lower grade injuries beginning with increasing range of motion before moving on to strengthening exercises and graded exposure to higher level exercise for return to baseline function.


Book an Appointment

Please book an appointment with one of our physiotherapists if you think you are suffering from this condition and would like to find out more.

We have Pure Physiotherapy clinics across the country including Norwich, Ipswich, Manchester, Bolton, Wakefield and Sheffield. Please view our clinics to find the closest physiotherapy clinic for you.


  1. Kim, S., Blank, A., & Strauss, E. (2014). Management of Type 3 Acromioclavicular Joint Dislocations. Bulletin of the Hospital for Joint Diseases72(1).
  2. Li, X., Ma, R., Bedi, A., Dines, D. M., Altchek, D. W., & Dines, J. S. (2014). Management of acromioclavicular joint injuries. JBJS96(1), 73-84.
  3. Culp, L. B., & Romani, W. A. (2006). Physical therapist examination, evaluation, and intervention following the surgical reconstruction of a grade III acromioclavicular joint separation. Physical therapy86(6), 857-869.
  4. Johansen, J. A., Grutter, P. W., McFarland, E. G., & Petersen, S. A. (2011). Acromioclavicular joint injuries: indications for treatment and treatment options. Journal of shoulder and elbow surgery20(2), S70-S82.
  5. Sirin, E., Aydin, N., & Mert Topkar, O. (2018). Acromioclavicular joint injuries: diagnosis, classification and ligamentoplasty procedures. EFORT open reviews3(7), 426-433.
  6. Gorbaty, J. D., Hsu, J. E., & Gee, A. O. (2017). Classifications in brief: Rockwood classification of acromioclavicular joint separations.
  7. Reid, D., Polson, K., & Johnson, L. (2012). Acromioclavicular Joint Separations Grades I–III. Sports medicine42(8), 681-696.
  8. Beitzel, K., Mazzocca, A.D., Bak, K., Itoi, E., Kibler, W.B., Mirzayan, R., Imhoff, A.B., Calvo, E., Arce, G., Shea, K. and of ISAKOS, U.E.C. (2014). ISAKOS upper extremity committee consensus statement on the need for diversification of the Rockwood classification for acromioclavicular joint injuries. Arthroscopy: The Journal of Arthroscopic & Related Surgery30(2), 271-278.
  9. Deans, C. F., Gentile, J. M., & Tao, M. A. (2019). Acromioclavicular joint injuries in overhead athletes: A concise review of injury mechanisms, treatment options, and outcomes. Current reviews in musculoskeletal medicine12(2), 80-86.
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