What You May Not Know About the AC Joint and Shoulder Pain

Shoulder Pain can stem from Rotator Cuff or AC Joint Injury

The first questions I imagine you would ask are, “What does shoulder pain have to do with the AC joint? What is an AC joint anyway?” Well I am here to tell you that there are more causes of shoulder pain than the rotator cuff tendons.

Shoulder Pain Can Stem From Rotator Cuff Or Ac Joint Injury

What is the AC joint? Where is it located?

AC joint stands for the Acromioclavicular joint. The joint is formed where the Clavicle (also known as the collarbone) and Acromion (also known as the shoulder girdle) come together superior to the shoulder joint. The joint is surrounded by fibrous cartilage that contains synovial fluid and a cartilaginous disc in the middle.

What does the AC joint Do?

The Acromioclavicular joint is one of several stabilizer joints of the shoulder girdle, a protective and stabilizing complex above the shoulder joint itself. The AC joint stabilizes the shoulder joint horizontally anterior to posteriorly along with other ligaments, the coracoacromial ligaments and coracoclavicular ligaments that stabilize the joint vertically.

Ac Joint Anatomical Diagram

AC Joint Pain due to Injury

  • AC joint separation is a common injury to the shoulder girdle and accounts for 10% of acute shoulder injuries. https://emedicine.medscape.com/article/92337-overview#a5
  • Common causes of AC joint injury include a fall on an outstretched arm or elbow, direct fall on the point of the shoulder with the arm at the side is also a common cause.
  • AC joint separation can be mild and only involve the joint itself or in more severe cases can sprain or disrupt the other ligaments supporting the shoulder girdle like the Coracoacromial ligaments and/ or Coracoclavicular ligaments.
  • Symptoms and pain associated with injury are often neck pain that radiates to the right shoulder along the deltoid muscle and top of the upper arm and forearm. There is pain with motion overhead and reaching.

AC Joint Pain from Arthritis

  • Arthritis of the AC joint can occur over time gradually and cause pain due to loss of surface cartilage in the joint itself. https://www.physio-pedia.com/Acromioclavicular_Arthritis
  • Pain can be caused by activities at work or in sports reaching overhead or lifting weights.
  • Symptoms include catching sensation and pain reaching overhead. There may be clicking, popping, grinding sensations with reaching overhead or shoulder movement.
  • Often there is pain at night while sleeping on the affected side.

How are AC Joint Issues Treated?

In situations of acute AC joint injury due to trauma the treatment is conservative for the most part unless there is a severe injury with tear of multiple ligaments and separation of multiple ligaments.

Treatment initially for mild injury or sprain of the AC Joint and surrounding structures includes sling for discomfort as needed, anti-inflammatory medications and rest followed by Physical Therapy.

Most shoulder injuries can be treated with Orthobiologic / Cellular Therapies such as Platelet-Rich Plasma, Bone Marrow Concentrate, and Prolotherapy. Once structural stability is restored, neuromuscular re-education and scapular stabilization through closed chain exercise can reduce the risk of re-injury.

Platelet Rich Plasma (PRP Therapy) has been used clinically to stimulate tissue repair and improve surgical outcomes since the 1990’s for wound care, oral surgery, hair growth, and musculoskeletal repair. The normal, natural healing cascade that we experience after daily activity is initiated by bleeding from microscopic tissue tears, which activates platelets containing abundant healing proteins including growth factors and cytokines. These proteins direct and coordinate the disinfection, clean-up, and regeneration of injured and degenerative tissue.

PRP injection therapy simulates the natural healing process by saturating your injured and degenerative tissue with your own concentrated platelets to dramatically enhance tissue repair. It provides a vigorous “kick start” to the regenerative process. The in-house laboratory at CHARM processes your Platelet Rich Plasma using state-of-the-art techniques to purify and quantify your platelet counts, to optimize your healing response.

Platelet Rich Plasma

Platelet Rich plasma and other solutions including Stem Cells from Bone Marrow can be used to treat many tendon/ ligament and musculoskeletal injuries to encourage the body’s own healing response.

Michele Hall

Physician Assistant

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