What is acromionclavicular (AC) joint pain?

An injury to the acromioclavicular (AC) joint causes pain and inflammation in the shoulder’s upper joint. It causes pinpoint soreness and pain, which is made worse by raising your arm across your body and above your head, especially when you’re carrying a lot of weight. It is most common in those who lift weights at the gym or who fall onto the outside of their shoulder, such as while falling off their bike. Conservative treatment does not usually work for acromioclavicular joint issues. Treatment options include physiotherapy and ultrasound-guided steroid injections.

What are the symptoms of acromioclavicular (AC) joint pain?

The symptoms of a acromioclavicular (AC) joint injury are:

  • When you touch the top of your shoulder, you will feel pain and tenderness.
  • You’re in pain because you’re lying on your side.
  • If you move your arm across your body’s midline and above shoulder level, you will experience pain.

What conditions can be mistaken for acromioclavicular (AC) joint pain?

If this does not sound like your discomfort, there are a number of different disorders that can cause pain similar to acromioclavicular joint pain, including:

  1. shoulder joint osteoarthritis
  2. frozen shoulder
  3. shoulder impingement
  4. rotator cuff pain
  5. subacromial bursitis

Acromioclavicular (AC) joint pain vs shoulder osteoarthritis (OA)

Pain on the top of the shoulder (above the arm) and soreness while touching the joint on the point of the shoulder are symptoms of acromioclavicular (AC) joint damage. OA of the shoulder joint, on the other hand, does not generate such localised pinpoint soreness. Although both disorders are characterised by pain induced by movements above the head, acromioclavicular (AC) joint pain is exacerbated by movement across the midline of the body, such as moving your arm across your neck.


The acromioclavicular joint (sometimes referred to as the ACJ) is a tiny, strong joint at the top of the shoulder. Between the acromion (part of the scapular bone) and the clavicle (collar bone) is the clavicle (see image below). During arm motions, the AC joint is crucial in maintaining the position of the shoulder blade and shoulder girdle (Mall et al.,2013). As a result, it is routinely subjected to high amounts of stress during daily activities such as work and sporting activities.

Acromioclavicular (AC) Joint Injuries injections treatment

Shoulder discomfort frequently occurs at the ACJ. The acromioclavicular joint was found to be involved in 9% of all shoulder girdle injuries by Mazzocca et al., (2007). The ACJ was also found to be responsible for 43.5 percent of all shoulder injuries in patients in their twenties in this study. Mall et al. (2013) discovered that the ACJ develops slowly and does not reach full ossification until the 25th year of life on average.

Shoulder discomfort frequently occurs at the ACJ. The acromioclavicular joint was found to be involved in 9% of all shoulder girdle injuries by Mazzocca et al., (2007). The ACJ was also found to be responsible for 43.5 percent of all shoulder injuries in patients in their twenties in this study. Mall et al. (2013) discovered that the ACJ develops slowly and does not reach full ossification until the 25th year of life on average.

According to Cadogan et al., (2013), ACJ discomfort can arise for a variety of reasons. These are some of the risk factors:

  • Trauma to the shoulder, such as fractures, dislocations, and ligament ruptures, is linked to the development of ACJ discomfort. A fall onto the point/side of the shoulder is a common cause of ACJ injury. The ACJ’s joint capsule and ligamentous structure can be damaged by trauma, resulting in joint instability.
  • The risk of ACJ osteoarthritis rises with age. The majority of instances of ACJ osteoarthritis occur after the fifth decade of life. Injury/trauma is frequently linked to the beginning of ACJ osteoarthritis before the age of 50.
  • Occupation – occupations that require repetitive shoulder movements or those require the use of heavy machinery might put additional strain on the shoulder joint. Osteoarthritis of the shoulder can be caused by repetitive movements or severe loading.
  • Overhead activities such as racquet or throwing sports, as well as weightlifting, are known to cause ACJ osteoarthritis.
  • ACJ discomfort can be caused by rheumatoid arthritis or other inflammatory disorders.

What is the best way to tell if you have an ACJ problem?

The discomfort at the top of the shoulder is a common symptom of ACJ pain. When performing above activities or crossing the arm over the torso, this is exacerbated. Symptoms of ACJ dysfunction or osteoarthritis become more painful and frequent as the condition progresses. This might cause persistent pain during daily activities and keep patients up at night.

AC joint injections in UK

Patients with acromioclavicular joint pain frequently find it difficult to move their arm above shoulder level, and stretching their arm across their body is particularly painful (see above image). Touching the affected area is frequently uncomfortable, and patients commonly experience pain while sleeping on the affected side.

After a fall onto the shoulder, symptoms may appear. A disruption of the joint, also known as an ACJ separation or sprain, can occur, resulting in a ‘step’ or ‘bump’ on the top of the shoulder.

How is acromioclavicular joint pain diagnosed?

One of our qualified specialists can make an ACJ pathology diagnosis. The evaluating doctor will first ask a series of questions to learn more about how and why your discomfort began. They may also ask you a series of questions about your medical history in order to rule out any medical disorders that may have contributed to your pain’s onset. Following your appointment, the clinician will perform a series of tests to aid in the development of an ACJ pathology hypothesis. Clinical testing alone is a good diagnostic tool, according to Cadogan et al., (2013), however diagnostic imaging is essential for a complete and thorough diagnosis.

AC Joint pain

If your doctor isn’t sure what’s wrong with you, they might send you for an x-ray, blood tests, or diagnostic ultrasound imaging. These will be explored further down in this article.


Plain x-ray imaging is the gold standard imaging for assessing both of bone and joint pathology. It is excellent for diagnosing fractures and the presence of osteoarthritis.

Blood tests

If your doctor suspects that your symptoms are the result of a systemic inflammatory disorder like rheumatoid arthritis, he or she may order a series of blood tests. This is usually done through your primary care physician.

Diagnostic ultrasound imaging

Diagnostic ultrasound imaging has been demonstrated to be as useful as MRI in assessing ACJ pathology, including osteoarthritis/degenerative changes, the presence of trauma, and the presence of swelling and inflammation that are commonly associated with ACJ pathology (European Society of Musculoskeletal Radiology., 2018). The ACJ can also be assessed during arm motions with a diagnostic ultrasound scan, letting the clinician to monitor the joint during uncomfortable activities.

Joint Injections has a highly skilled team of qualified musculoskeletal sonographers and seasoned physiotherapists. To make an appropriate diagnosis, your clinician will employ a mix of clinical testing as well as a musculoskeletal ultrasound scan.

How do we treat acromioclavicular joint pain?

A course of physiotherapy, over-the-counter medicines, and a brief time of rest from aggravating factors can all help with acromioclavicular joint pain. Corrective strengthening and stretching rehabilitation exercises, manual treatments such as soft tissue release, and posture guidance are frequently used in physiotherapy.

What if therapeutic approaches don’t work?

An ultrasound guided steroid injection may be helpful for you if conservative treatment, such as physiotherapy and rehabilitation, has failed and your symptoms continue.

We would recommend that you complete the following steps before contemplating a steroid injection:

  • Avoiding irritating motions and activities, such as overhead workouts in the gym, is a good example.
  • Local cold massage or anti-inflammatory creams — because the joint is so superficial, topical medicine applied to the painful region may be beneficial (speak to a pharmacist).
  • Physiotherapy is used to relieve pain, restore normal joint mobility, and strengthen muscles. Sports tape may also be used to relieve pressure on the joint.

When injected directly into the joint under ultrasound guidance, steroid injections are highly helpful for all forms of shoulder discomfort, including acromioclavicular joint pain. A powerful anti-inflammatory, steroid can dramatically relieve joint discomfort. The medical literature strongly supports this treatment.

Ultrasound guidance has been demonstrated to be substantially more accurate than landmark-based injections for the acromioclavicular joint (100 percent vs 35 percent, respectively) in the evidence base (Daniels et al, 2018, Aly et al., 2015). This injection technique includes utilising an ultrasonic scanner to guide the needle straight into the joint. The use of this method has also been found to result in fewer post-injection problems and substantially faster pain alleviation.

If acromioclavicular joint discomfort has been present for more than 6 weeks and has not improved with physiotherapy, Joint Injections recommends steroid injections. However, if you have a separation as a result of a fall onto your shoulder, we usually recommend waiting a little longer because steroid might suppress your natural healing mechanisms. Depending on the degree of the separation, separation injuries might take a bit longer to heal.

How many injections do you need?

The majority of our patients just need a single shot. One injection usually offers the necessary pain relief, as well as a window of opportunity to work on regaining your shoulder’s full range of motion and function. More than one injection may be necessary in situations with known osteoarthritis or if the joint is extremely inflamed.

Clinical tests and a diagnostic ultrasound scan are both part of a Joint Injections evaluation. As a result, a very precise and accurate diagnosis and, as a result, successful therapy are possible. Prior to doing an ultrasound guided injection, your physician will be able to advise and prescribe the most beneficial drug for you. All guided injections are performed the same day at Joint Injections, and there is no requirement for a referral from a specialist or a GP.