Acromioclavicular (AC) Joint Repair

The acromioclavicular (AC) joint connects the collarbone (clavicle) to the acromion of the shoulder blade. It plays a vital role in shoulder mobility. When this joint becomes injured—either from trauma, overuse, or degeneration—patients may experience pain and reduced shoulder function. AC joint injuries are most common in athletes, especially those involved in contact sports or overhead motions, and in individuals with occupations that require repetitive lifting.

How Common It Is and Who Gets It? (Epidemiology)

AC joint injuries are relatively common, particularly among individuals who participate in high-impact sports, manual labor, or heavy lifting. These injuries are classified by the severity of the damage, ranging from mild sprains to complete dislocations. The Rockwood scale (Types I–VI) is used to categorize AC joint injuries, with higher grades associated with more severe damage and dysfunction.

Why It Happens – Causes (Etiology and Pathophysiology)

The primary cause of AC joint injuries is trauma, often resulting from a fall onto the shoulder or a direct blow to the joint. Overuse can also contribute to degenerative changes, especially in athletes or workers who perform repetitive overhead motions. As the AC joint sustains damage, the ligaments that stabilize the joint may tear or stretch, leading to pain, instability, and impaired movement.

How the Body Part Normally Works? (Relevant Anatomy)

The AC joint is a synovial joint, connecting the distal end of the clavicle with the acromion. It plays a crucial role in enabling a wide range of shoulder motions, including overhead lifting and rotating movements. Several ligaments, including the acromioclavicular and coracoclavicular ligaments, provide stability to the joint. These ligaments are responsible for preventing excessive movement and ensuring smooth motion.

What You Might Feel – Symptoms (Clinical Presentation)

Symptoms of an AC joint injury can include:

• Pain: Localized pain at the top of the shoulder, often worsened by overhead motions or lifting.
• Swelling: Visible swelling or a bump at the AC joint.
• Instability: Difficulty moving the shoulder, especially during certain motions like reaching across the body or lifting overhead.
• Tenderness: Pain when the joint is palpated or pressed.

How Doctors Find the Problem? (Diagnosis and Imaging)

Diagnosis typically involves:

• Physical Examination: The doctor may perform special tests, such as the Cross-body Adduction test, to reproduce pain and confirm the AC joint involvement.
• X-rays: Standard X-rays help assess the joint space and identify any bone displacement, joint instability, or the presence of osteophytes (bone spurs).
• MRI/CT scans: These advanced imaging techniques are useful for evaluating soft tissue damage, including ligament tears, cartilage injury, and associated joint inflammation.
• Ultrasound: In some cases, an ultrasound is used to assess the soft tissue structures and joint fluid.

Classification

AC joint injuries are classified using the Rockwood Classification:

• Type I: Sprain of the AC ligament without clavicle displacement.
• Type II: Partial tear of the AC ligament, with slight clavicle displacement.
• Type III: Complete tear of both the AC and CC ligaments, leading to visible displacement of the clavicle.
• Type IV-VI: Severe displacement or dislocation of the clavicle, often requiring surgical intervention.

Other Problems That Can Feel Similar (Differential Diagnosis)

Several other conditions can mimic AC joint injury symptoms, including rotator cuff tears, shoulder impingement syndrome, and labral tears. Proper diagnosis is essential to distinguish these conditions and determine the best treatment approach.

Treatment Options

Non-Surgical Care:

• • Rest: Avoiding activities that stress the AC joint.
  • Ice and NSAIDs: To reduce inflammation and pain.
  • Physical Therapy: Targeted exercises to restore shoulder mobility and strength.
  • Steroid Injections: To reduce inflammation in the joint.

Surgical Care:

• • AC Joint Resection: For severe injuries, removal of the distal clavicle may be necessary.
  • Arthroscopic Surgery: Minimally invasive techniques to remove damaged tissues and stabilize the joint.

Recovery and What to Expect After Treatment

Post-surgical recovery typically involves:

• Immobilization: Wearing a sling for a few weeks to protect the joint.
• Physical Therapy: Restoring strength and flexibility, with a gradual return to normal activities over 3–6 months.
• Pain Management: Use of anti-inflammatory drugs or other pain relief methods to manage discomfort during recovery.

Possible Risks or Side Effects (Complications)

Complications, though rare, can include:

• Infection: As with any surgery, there’s a risk of infection at the incision site.
• Instability: Incomplete healing or failure of the surgical repair may result in ongoing shoulder instability.
• Shoulder Stiffness: Some loss of motion may occur if rehabilitation is not followed carefully.

Long-Term Outlook (Prognosis)

Most patients experience excellent long-term outcomes, with significant pain relief and restored shoulder function, especially after surgical repair. However, a small percentage may experience occasional discomfort or reduced mobility.

Out-of-Pocket Costs

Medicare

CPT Code 23545 – Clavicle (CC) Reconstruction (Surgical Repair of Clavicle Fracture or Dislocation): $89.05

CPT Code 23550 – Acromioclavicular (AC) Joint Stabilization (Surgical Repair of AC Joint Separation): $136.68

Medicare Part B typically covers 80% of the approved cost for these procedures once your annual deductible has been met, leaving you responsible for the remaining 20%. Supplemental Insurance plans such as Medigap, AARP, or Blue Cross Blue Shield generally cover that remaining 20%, minimizing or eliminating out-of-pocket expenses for Medicare-approved surgeries. These supplemental plans coordinate with Medicare to fill the coverage gap and reduce the patient’s financial responsibility.

If you have Secondary Insurance, such as TRICARE, an Employer-Based Plan, or Veterans Health Administration coverage, it serves as a secondary payer. These plans typically cover any remaining balance, including coinsurance or small deductibles, which generally range from $100 to $300, depending on your plan and provider network.

Workers’ Compensation

If your clavicle reconstruction (CPT 23545) or AC joint stabilization (CPT 23550) is required due to a work-related injury, Workers’ Compensation will cover all associated medical expenses, including surgery, rehabilitation, and follow-up care. You will not have any out-of-pocket expenses, as the employer’s insurance carrier directly covers all approved treatments.

No-Fault Insurance

If your shoulder surgery is needed because of an automobile accident, No-Fault Insurance will typically cover the total cost of your treatment, including surgery and postoperative care. The only potential out-of-pocket cost may be a small deductible or co-payment depending on your insurance policy.

Example

John Davis required AC joint stabilization (CPT 23550) after a shoulder injury. His estimated Medicare out-of-pocket cost for the surgery was $136.68. Since John had supplemental insurance through Blue Cross Blue Shield, his remaining balance was fully covered, leaving him with no out-of-pocket expenses for the procedure.

Frequently Asked Questions (FAQ)

Q. What is the acromioclavicular (AC) joint?
A. The AC joint is where the collarbone (clavicle) meets the highest point of the shoulder blade (acromion).

Q. What are common causes of AC joint injuries?
A. AC joint injuries often result from direct trauma to the shoulder, such as falling on the shoulder or being hit during contact sports.

Q. What are the symptoms of an AC joint injury?
A. Symptoms can include pain at the top of the shoulder, swelling, a visible bump, limited range of motion, and discomfort during shoulder movement.

Q. How is an AC joint injury diagnosed?
A. Diagnosis is typically made through a physical examination and confirmed with X-rays, and in some cases, MRI or CT scans.

Q. What are the treatment options for AC joint injuries?
A. Treatment options include non-surgical methods such as rest, ice, medications, and physical therapy, and surgical repair for more severe cases.

Q. When is surgery considered for an AC joint injury?
A. Surgery is considered when there is a complete tear of the ligaments, persistent instability, or failure of conservative treatment.

Q. What does AC joint repair surgery involve?
A. The surgery involves realigning the clavicle and securing it in place with sutures, grafts, or hardware to stabilize the joint and allow healing.

Q. How long does it take to recover from AC joint surgery?
A. Recovery can take several months, typically including a period of immobilization followed by physical therapy.

Q. What is the purpose of physical therapy after AC joint surgery?
A. Physical therapy helps restore range of motion, strength, and function in the shoulder after surgery.

Q. What is the success rate of AC joint repair surgery?
A. AC joint repair surgery generally has a high success rate, especially when the joint is stabilized properly and post-operative care is followed.

Q. Are there risks associated with AC joint repair surgery?
A. Yes, potential risks include infection, stiffness, loss of motion, hardware problems, or incomplete healing.

Q. How long do patients need to wear a sling after AC joint surgery?
A. Patients usually need to wear a sling for several weeks to protect the repair during the early healing phase.

Q. Can patients return to sports after AC joint repair?
A. Most patients can return to sports after full recovery, but this depends on the severity of the injury and the demands of the sport.

Q. What type of anesthesia is used during AC joint repair surgery?
A. General anesthesia is typically used, sometimes combined with a regional nerve block for pain control.

Q. Is AC joint repair surgery performed arthroscopically or through open surgery?
A. It can be performed arthroscopically or through an open approach depending on the severity of the injury and the surgeon’s preference.

Q. What is the role of ligament reconstruction in AC joint repair?
A. Ligament reconstruction may be used to restore stability by replacing torn ligaments with graft tissue.

Q. How is the stability of the clavicle maintained during healing?
A. Stability is maintained using sutures, buttons, plates, or grafts to hold the clavicle in position while the ligaments heal.

Q. Can AC joint injuries heal without surgery?
A. Yes, many AC joint injuries, especially mild to moderate ones, can heal with conservative treatment.

Q. What is the long-term outlook after AC joint repair surgery?
A. Most patients regain good shoulder function and return to normal activities, although some may experience occasional discomfort or weakness.

Summary and Takeaway

AC joint injuries can significantly impair shoulder function and quality of life. While mild cases often respond to conservative care, more severe injuries may require surgical intervention. Arthroscopic AC joint stabilization provides a minimally invasive option with high patient satisfaction, quick recovery, and minimal complications. Early surgical intervention, combined with proper rehabilitation, typically leads to excellent long-term outcomes.

Clinical Insight & Recent Findings

Recent studies suggest that combined coracoclavicular and acromioclavicular ligament reconstruction using modern techniques provides comparable outcomes to open procedures, with faster recovery times and fewer complications. These advances make arthroscopic surgery an increasingly preferred option for patients with severe AC joint injuries.

Who Performs This Treatment? (Specialists and Team Involved)

Orthopedic surgeons specializing in shoulder and upper extremity surgery typically perform AC joint surgeries. Rehabilitation specialists are often involved in post-operative care.

When to See a Specialist?

Consult a specialist if you experience persistent AC joint pain, especially after an injury, or if conservative treatments do not provide relief.

When to Go to the Emergency Room?

Seek emergency care if you experience severe shoulder pain, sudden immobility, or signs of infection (fever, redness, swelling) after surgery.

What Recovery Really Looks Like?

Recovery from AC joint surgery requires several weeks of rest, followed by physical therapy to restore shoulder function. Most patients resume normal activities within 3–6 months, depending on the type of surgery.

What Happens If You Ignore It?

Ignoring AC joint injuries can lead to persistent pain, joint instability, and further degeneration. Early intervention can prevent worsening symptoms and improve long-term outcomes.

How to Prevent It?

Prevent AC joint injuries by using proper lifting techniques, avoiding repetitive overhead motions, and strengthening shoulder muscles.

Nutrition and Bone or Joint Health

A diet rich in calcium and vitamin D supports bone health and may help prevent degenerative joint conditions.

Activity and Lifestyle Modifications

After surgery, engage in low-impact activities to maintain fitness while avoiding stress on the shoulder. Full activity can resume after healing and rehabilitation.