Acromioclavicular (AC) Joint Dislocations

What is the Acromioclavicular (AC) Joint?

The AC joint is stabilized by the AC joint capsules, four AC ligaments, and a pair of CC (coracoclavicular) ligaments.

What causes AC Joint Dislocation?

AC joint can be injured due to a direct blow to the shoulder or, more commonly, from a fall with a direct impact on the shoulder. This trauma can result in the sprain or complete rupture of the ligaments stabilizing the AC joint, leading to the separation or dislocation of the AC joint. The collarbone (clavicle) can dislocate in several directions concerning the tip of the shoulder blade (acromion), with upward (superior) migration being the most common type.

What Are the Symptoms of AC Joint Dislocation?

Patients with AC joint injury may experience pain, swelling, and/or deformity on the tip of the shoulder where the AC joint is located.

How is it Diagnosed?

AC joint injury can be diagnosed by your doctor after assessing your symptoms, conducting a shoulder examination, and performing simple X-ray imaging.

What Are the Treatments for AC Joint Dislocation?

The treatment of AC joint injury depends on its severity, usually graded based on the amount and direction of AC joint dislocation observed on X-ray.

Low-grade injuries can be treated non-operatively, typically involving a short period of arm sling usage to allow the injury to settle. This is followed by physiotherapy and a gradual return to sports or activities. Patients are usually advised to avoid excessive overhead weight during the early phase of recovery to allow the ligaments to heal.

Patients with high-grade injuries might require an operation to restore the stability of the AC joint.

What are the Surgeries for AC Joint Dislocation?

The goal of the surgery is to reduce the dislocation and restore stability to the AC joint. This can be achieved through a mini-open incision or keyhole (arthroscopic) techniques. Various implants, such as hook plates, fibertape, tightrope, or suture anchors, might be used to maintain stability while allowing the native AC and CC ligaments to heal.

In cases of chronic injury (> 3 weeks old), a tendon graft reconstruction is usually necessary due to concerns about the healing potential of the native ligaments.

The surgery is commonly performed as a day procedure. You might be advised to wear an arm sling in the early post-operative period to facilitate the healing of the native or reconstructed ligaments. Rehabilitation is necessary thereafter to regain range of motion and strength.

Acromioclavicular (AC) Joint Arthritis

The AC joint is the connection between the collarbone (clavicle) and the tip of the shoulder blade (acromion). Located at the top outer corner of the shoulder, the AC joint enables gliding and rotational motion between the shoulder blade and the collarbone.The AC joint is stabilized by the AC joint capsules, four AC ligaments, and a pair of CC (coracoclavicular) ligaments.

Like other joints in the body, it is susceptible to arthritis, a condition that causes inflammation and degeneration of the joint. ACJ arthritis can significantly impair shoulder function and lead to discomfort or pain.

ACJ arthritis typically occurs in 2 groups of patients:

1. young active patients in their late 20s to 30s involving in excessive overhead movement such as contact athletes, collision sportsmen, manual labour worker or weight lifter.

2. older patient with wear and tear around the AC joint over time

What are the causes of Acromioclavicular (AC) Joint arthritis?

The common causes include:

1. Degenerative: Like other forms of osteoarthritis, ACJ arthritis often results from the natural wear and tear that occurs over time. As people age, the cartilage that cushions the ends of the bones within the joint may gradually deteriorate, leading to friction, inflammation, and joint degeneration.

2. Trauma: Previous shoulder injuries, such as dislocations, fractures, or sprains, can predispose individuals to ACJ arthritis. These injuries may disrupt the normal alignment and stability of the ACJ, accelerating the degenerative process.

3. Overuse or Repetitive Stress: Activities that involve repetitive overhead movements or heavy lifting can place excessive strain on the ACJ, leading to accelerated joint degeneration. Athletes participating in sports such as weightlifting, swimming, or tennis may be at increased risk of developing ACJ arthritis due to repetitive stress on the shoulder joint.

4. Inflammatory Arthritis such as rheumatoid arthritis.

5. Infection

What are the symptoms of ACJ Arthritis?

The symptoms of ACJ arthritis can vary in severity from mild discomfort to significant pain and restricted movement. Common symptoms include:

Pain: Persistent pain around the top of the shoulder is a hallmark symptom of ACJ arthritis. The pain may worsen with certain movements, such as reaching overhead or across the body.

Swelling: Inflammation of the ACJ can cause noticeable swelling and tenderness at the joint. Limited Range of Motion: As arthritis progresses, individuals may experience stiffness and reduced flexibility in the shoulder joint, making it challenging to perform certain activities.

Crepitus: Some people may notice a grinding sensation or audible clicking or popping sounds when moving the shoulder joint.

Weakness: Weakness in the shoulder muscles may develop due to pain and limited movement, further compromising function.

How is ACJ arthritis diagnosed?

Diagnosing ACJ arthritis typically involves a combination of medical history review, physical examination, and imaging studies. During the physical examination, the orthopaedic surgeon may assess the range of motion, stability, and tenderness of the shoulder joint. Imaging studies such as X-rays, may be ordered to visualize the extent of joint damage and rule out other underlying conditions.

What are the treatment options for ACJ Arthritis?

Treatment for ACJ arthritis aims to alleviate pain, improve function, and slow down the progression of joint degeneration. Depending on the severity of symptoms and the individual's overall health, treatment options may include:

1. Pain Management: Nonsteroidal anti-inflammatory drugs (NSAIDs), corticosteroid injections, or topical analgesics can help reduce pain and inflammation.

2. Physical Therapy: Specific exercises and stretches prescribed by a physical therapist can improve shoulder strength, flexibility, and stability.

3. Activity Modification: Avoiding activities that exacerbate symptoms, such as heavy lifting or overhead movements, can help prevent further joint irritation.

4. Injection with corticosteroid

5. Surgery: In cases where conservative measures fail to provide adequate relief, surgical intervention may be considered.

What is the surgical treatment for ACJ arthritis?

Arthroscopic ACJ debridement is a minimally invasive surgical procedure performed to alleviate pain and improve shoulder function in individuals with ACJ arthritis or related conditions. This procedure involves using a small camera, called an arthroscope, and specialized surgical instruments inserted through tiny incisions around the shoulder joint.

Arthroscopic Acromioclavicular joint (ACJ) Debridement:

During arthroscopic ACJ debridement, the surgeon visualizes the inside of the shoulder joint to assess the extent of joint damage, including cartilage wear, bone spurs, and inflamed soft tissues. The surgeon then removes or debrides the damaged tissue, smoothing out rough surfaces and removing any loose fragments that may be causing pain or impeding joint movement. Sometimes a portion of the distal clavicle (the outer end of the collarbone) may be resected to alleviate pain and improve joint function.