Is Acromioclavicular Joint Arthritis of the Shoulder the reason for your nagging Shoulder Pain?

Nagging shoulder pan?


The human shoulder is a marvel of intricate anatomy, composed of a complex network of bones, ligaments, tendons, and joints. The acromioclavicular joint (AC joint) is a small but crucial component of the shoulder structure. While often overlooked, the AC joint can be the source of debilitating pain, especially when afflicted by arthritis.

Anatomy of the Acromioclavicular Joint

Illustrative depiction of Acromioclavicular joint arthritisThe AC joint is located at the junction of the acromion (a part of the shoulder blade) and the clavicle (collarbone). It is a synovial joint, enclosed by a capsule and supported by ligaments. The AC joint allows for overhead arm movement and is essential for the normal function of the shoulder.

Causes of AC Joint Arthritis

The causes of Acromioclavicular (AC) joint arthritis are multifactorial, often resulting from a combination of factors. AC joint arthritis typically involves the gradual degeneration of the cartilage and tissues within the joint. Here are some of the common causes and contributing factors:


Age-related wear and tear on the AC joint is a primary cause of arthritis. Over time, the cartilage that cushions the joint can naturally deteriorate, leading to the development of arthritis.


A history of shoulder injuries or trauma, such as dislocations, fractures, or repetitive stress, can significantly increase the risk of AC joint arthritis. Trauma can damage the joint’s structures and accelerate the degeneration process.

Overuse and Repetitive Movements

Individuals engaged in activities that involve repetitive overhead motions, such as weightlifting, manual labor, or certain sports like weightlifting and overhead throwing, are at a higher risk of developing AC joint arthritis due to constant strain and wear on the joint.


Genetic factors can predispose some individuals to the development of AC joint arthritis. If there’s a family history of joint problems, the risk may be higher.


AC joint arthritis is more commonly seen in men, especially in middle-aged and older individuals. The reasons for this gender discrepancy are not entirely clear but could be related to variations in anatomy and physical activity.

Inflammatory Conditions

Certain inflammatory conditions, such as rheumatoid arthritis or systemic lupus erythematosus, can contribute to the development of AC joint arthritis. These conditions can cause chronic inflammation and damage to joint structures.

Degenerative Changes

As part of the natural aging process, the AC joint can undergo degenerative changes that lead to the breakdown of cartilage and other joint tissues. This degeneration can vary from person to person.

Poor Posture

Prolonged poor posture can put added stress on the AC joint. People who slouch or have a forward-leaning shoulder posture may be more prone to developing arthritis in this joint.

Occupational Factors

Certain occupations that require frequent heavy lifting or overhead work can increase the risk of AC joint arthritis. These repetitive motions can accelerate joint degeneration.

Prior Surgical Procedures

Previous surgical procedures on the shoulder, especially those involving the AC joint itself, can potentially predispose individuals to AC joint arthritis

Symptoms of AC Joint Arthritis

Acromioclavicular (AC) joint arthritis is characterized by a range of symptoms that can vary in severity. These symptoms often develop gradually and may worsen over time. Common signs and symptoms of AC joint arthritis include:

  • Shoulder Pain : Pain in the front or top of the shoulder is the hallmark symptom of AC joint arthritis. This pain can range from mild to severe and is typically felt during activities that involve raising the arm or using the shoulder, such as reaching overhead or lifting objects.
  • Pain with Overhead Movements : Activities that require the shoulder to move overhead, like reaching for items on high shelves, lifting objects, or participating in sports that involve overhead motions, can exacerbate the pain.
  • Tenderness : The area over the AC joint may become tender to the touch. This tenderness can be a result of inflammation and degeneration in the joint.
  • Swelling : Inflammation within the AC joint may lead to localized swelling around the joint. This swelling can sometimes be visible and is often accompanied by warmth in the area.
  • Reduced Range of Motion : AC joint arthritis can limit the range of motion in the affected shoulder. Patients may find it challenging to fully raise their arms overhead, reach behind their back, or perform certain daily activities.
  • Crepitus : Patients may experience a grating or popping sensation when moving the shoulder. This is often due to the roughened joint surfaces and the loss of smooth cartilage.
  • Night Pain : Some individuals with AC joint arthritis report increased pain during the night, especially when lying on the affected shoulder. This can lead to sleep disturbances.
  • Weakness : Pain and inflammation in the AC joint can cause weakness in the shoulder. Patients may find it difficult to perform tasks that require strength, such as lifting heavy objects or pushing and pulling motions.
  • Radiating Pain : In some cases, pain from the AC joint can radiate down the arm, leading to discomfort in the upper arm or even the neck.
  • Stiffness : Stiffness in the shoulder joint is a common symptom. Patients may find it challenging to perform simple activities that involve shoulder mobility.

Diagnosis of AC Joint Arthritis

The diagnosis of Acromioclavicular (AC) joint arthritis typically involves a comprehensive evaluation by a healthcare professional, often an orthopedic or pain management specialist. The diagnostic process includes a combination of clinical assessments, medical history review, and various imaging studies to confirm the presence of AC joint arthritis. Here’s an overview of the diagnostic steps:

Medical History and Physical Examination

  1. Your healthcare provider will begin by taking a detailed medical history. They will ask about your symptoms, their onset, and any factors that exacerbate or alleviate the pain.
  2. A physical examination will be conducted to assess the affected shoulder. The healthcare provider will check for tenderness, swelling, range of motion limitations, and any other signs that may point to AC joint arthritis.

Clinical Tests

A common clinical test used in the evaluation of AC joint arthritis is the cross-body adduction test. During this test, the examiner places downward pressure on the arm, causing pain if the AC joint is affected. Positive findings in this test can be indicative of AC joint pathology.

Imaging Studies

X ray showing AC joint arthritis

  • X-rays : X-ray images are often the initial imaging modality used to assess the AC joint. They can reveal structural abnormalities, such as joint space narrowing, bone spurs (osteophytes), or irregularities in the clavicle and acromion.
  • Magnetic Resonance Imaging (MRI) : An MRI scan provides more detailed images of the soft tissues around the AC joint, including the cartilage and ligaments. This can help assess the extent of joint degeneration and rule out other shoulder conditions.
  • Ultrasound : Ultrasound imaging can also be used to evaluate the AC joint and surrounding soft tissues. It is particularly useful for assessing inflammation and identifying fluid accumulation within the joint.

Diagnostic Injections

In some cases, a diagnostic injection may be performed to confirm the source of shoulder pain. A local anesthetic is injected directly into the AC joint. If the injection provides temporary relief from pain, it suggests that the AC joint is the source of the discomfort, supporting the diagnosis of AC joint arthritis.

Blood Tests

While less commonly used, blood tests may be conducted to rule out inflammatory arthritis conditions that can mimic the symptoms of AC joint arthritis, such as rheumatoid arthritis or systemic lupus erythematosus.

Management of AC Joint Arthritis

While less commonly used, blood tests may be conducted to rule out inflammatory arthritis conditions that can mimic the symptoms of AC joint arthritis, such as rheumatoid arthritis or systemic lupus erythematosus.

Conservative Management

  • Medications : Non-steroidal anti-inflammatory drugs (NSAIDs) may be prescribed to help reduce pain and inflammation. In some cases, pain-relieving medications or topical treatments can also be beneficial.
  • Physical Therapy : Physical therapy plays a crucial role in managing AC joint arthritis. A physical therapist can design a tailored exercise program to improve shoulder strength and flexibility while minimizing pain. These exercises may include range of motion exercises, strengthening exercises, and postural correction techniques.
  • Lifestyle Modifications : Patients are often advised to make certain lifestyle modifications, such as avoiding activities that exacerbate symptoms, maintaining good posture, and using assistive devices to reduce stress on the joint.
  • Heat and Cold Therapy : Applying heat or cold packs to the affected area can help reduce pain and inflammation.

Interventional Approaches

Image-guided injection treatments are interventional approaches that can be effective for managing AC joint arthritis, and they are often offered at specialized clinics like Alleviate Pain Clinic. These treatments include

  • Corticosteroid Injections : In cases where pain and inflammation are significant, corticosteroid injections can be administered directly into the AC joint. These injections are performed under image guidance, such as ultrasound or fluoroscopy, to ensure precise placement of the medication. The corticosteroid helps reduce inflammation and relieve pain, providing long-lasting relief for many patients.
  • Hyaluronic Acid Injections : Another image-guided injection treatment involves the use of hyaluronic acid (viscosupplementation). This treatment is aimed at restoring lubrication and cushioning within the AC joint, potentially offering relief from pain and improving joint function.
  • Platelet-Rich Plasma (PRP) Injections : Patient undergoing Acromioclavicular joint -Platelet Rich Plasma Injection under fluoroscopy at Alleviate Pain Clinic. Image- Courtesy Alleviate Pain Clinic
    PRP is derived from the patient’s blood and contains growth factors that can stimulate tissue healing and reduce pain and slow down the degenerative process of arthritis.These are administered under fluoroscopic or ultrasound guidance.


Exercise Recommendations

While exercise is an important component of managing AC joint arthritis, it’s crucial to engage in the right exercises and avoid those that may worsen symptoms. Here are some exercise recommendations:

Recommended Exercises

  • Range of Motion Exercises : Gentle range of motion exercises can help maintain shoulder mobility and prevent stiffness.
  • Strengthening Exercises : Targeted strengthening exercises for the shoulder and upper back muscles can improve joint stability. These may include exercises for the rotator cuff, deltoid, and scapular muscles.
  • Posture Correction : Exercises to improve posture can help reduce stress on the AC joint. These exercises may include scapular retractions and postural awareness training.

Exercises to Avoid

  • Overhead Activities : Avoid exercises or activities that involve repetitive overhead movements, as they can exacerbate pain.
  • Heavy Weightlifting : Activities that involve heavy weightlifting and excessive strain on the shoulder should be avoided.
  • High-Impact Activities : High-impact activities or sports that place significant stress on the AC joint should be minimized to prevent further joint degeneration.


AC joint arthritis is a common source of shoulder pain that can significantly impact one’s quality of life. Accurate diagnosis, followed by a combination of non-surgical management and image-guided injection treatments, can provide effective relief. Exercise, when tailored to the individual’s needs and capabilities, can aid in maintaining shoulder function and mobility while avoiding further damage. Patients should consult with a medical professional at a specialized clinic like Alleviate Pain Clinic for personalized evaluation and treatment recommendations based on their unique condition and needs.

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