Are You Experiencing
AC Joint Pain?

AC joint pain can create limited shoulder motion, limited shoulder strength, and an inability to use your shoulder in a normal manner. How can you tell if your AC joint is the source of your shoulder pain and what can you do if it is?



What is the AC Joint?

Shoulder Anatomy

The acromioclavicular (or AC) joint is the joint created by the end of the collar bone (clavicle) connecting to the acromion of the shoulder blade (scapula).

Pain in this region of the shoulder is most commonly caused by trauma, specifically falling on either an outstretched arm or a fall landing directly on the tip of the AC joint.



When such a trauma occurs, it is called a sprain as the ligament that connects the bones becomes stretched or torn. This type of AC sprain is also called a shoulder separation.

ac joint injury


Shoulder separations are classified as either 1st (mild), 2nd (moderate), or 3rd (severe) degree sprains. A 3rd degree AC joint sprain is the most severe with the result being what is termed a “stair step” deformity. This is when the end of the clavicle appears elevated because the ligament connecting the bones is completely torn.

AC joint injury

A less common source of AC joint pain is an AC joint that has become stiff and arthritic. No recent trauma is associated with this type of injury, but rather the pain and limited mobility of the joint gradually worsens over time. As the joint becomes more stiff it affects the mechanics of the shoulder as a whole, generally leading to pain right at the tip of the shoulder.


Typical Symptoms

Most commonly, when the AC joint is involved in shoulder pain, the AC joint itself will be very tender to the touch. Pain will be very specific to the tip of the shoulder.

Lifting the arm up and reaching overhead will often be painful. Reaching into overhead cabinets, washing your hair, and getting shirts on or off are symptomatic. And, reaching across your body to the opposite shoulder will also recreate pain in the AC region. Sleeping on the involved shoulder will reproduce pain and may wake you at night.



Typical Treatment

For AC joint pain that is the result of trauma, ice and rest is the initial treatment of choice. In addition, over the counter anti-inflammatory medication can also be helpful to reduce joint inflammation (consult your doctor regarding medications). Utilizing ice therapy (no heat!) to reduce pain and swelling is also recommended. For best results, apply ice to the shoulder 10 to 15 minutes, three times a day.

Often because the weight of the arm hanging next to the body can cause discomfort, utilizing a sling can help in reducing pain and decreasing stress on the joint.

The severity of the injury generally determines how quickly pain will diminish and function will improve. Most sprains take 6 to 8 weeks to heal. In rare cases when a 3rd degree sprain occurs, healing will take longer and surgery may be warranted.

AC joint pain unrelated to recent trauma most likely is an indication of arthritic changes in the joint. Ice can be helpful in reducing the local inflammation associated with these arthritic changes. Of course, with all joint arthritis, anti-inflammatory medications can be helpful (consult your doctor regarding medications). Often if medication is not effective, a steroid injection into the AC joint can greatly improve joint pain.


Physical Therapy Exercise

As with other joint sprains, treatment goals include reducing inflammation, restoring range of motion (ROM), and restoring strength.

The following is a link to a physical therapy exercise program for assisting in restoring ROM and strength following an AC joint injury: Exercises for AC Joint Pain.

In cases where the joint is stiff, seeking physical therapy treatment can also be greatly helpful as manual mobilization of the joint may be necessary to improve joint mobility. For arthritic joints, restoring normal ROM is necessary to reduce pain.

Another type of physical therapy treatment for arthritic AC joints is a modality called iontophoresis. This modality involves the use of an electrode in order to deliver an anti-inflammatory medication and can be very effective in reducing local joint inflammation.


Summary

• AC joint pain is most often related to trauma.

• The most serious of AC sprains results in a stair step deformity.

• Rest, ice, medication, and at times a sling can help reduce joint pain.

• Follow the exercises for AC joint pain to restore your shoulder mobility and strength and help to reduce your shoulder joint pain.

AC joint pain can by annoying and limiting. Following simple recommendations can help to relieve your AC pain and get you back to the activity you enjoy.




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References

Skeletal Radiol. 2011 Jul;40(7):831-42. Epub 2010 Jun 6. Clavicle and acromioclavicular joint injuries: a review of imaging, treatment, and complications. Melenevsky Y, Yablon CM, Ramappa A, Hochman MG.

Clin Sports Med. 2008 Oct;27(4):763-88. Acromioclavicular joint problems in athletes and new methods of management. Rios CG, Mazzocca AD.


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