The acromioclavicular (AC) joint is the connection between the collarbone (clavicle) and the highest point of the shoulder blade (acromion). Injuries to this joint are common, especially among young active individuals, typically caused by a direct blow to the shoulder—such as falling onto the shoulder or being hit in contact sports. AC joint injuries are categorized by severity, with types I and II being mild and often healing without surgery, while types IV through VI are severe and require surgical repair. Type III injuries can be treated either surgically or non-surgically, depending on the patient’s activity level and symptoms.
How Common It Is and Who Gets It? (Epidemiology)
AC joint injuries are common in athletes, particularly those involved in contact sports, as well as individuals who engage in activities that put stress on the shoulder. The incidence is higher in younger individuals, especially males, who tend to engage in more physically demanding activities. While most injuries are non-surgical, about 10–15% of AC joint injuries require surgical intervention, particularly in cases of more severe injury or chronic instability.
Why It Happens – Causes (Etiology and Pathophysiology)
AC joint injuries often occur due to direct trauma to the shoulder, such as falling onto an outstretched arm or a direct blow during sports. These injuries result in damage to the ligaments that stabilize the AC joint. The most common mechanism is a fall on the shoulder, which causes separation between the acromion and the clavicle. This can lead to various grades of AC joint dislocation, with more severe injuries involving complete ligament rupture and significant bone displacement.
How the Body Part Normally Works? (Relevant Anatomy)
The AC joint is where the acromion (a part of the scapula) meets the clavicle (collarbone). This joint is stabilized by the acromioclavicular ligaments and the coracoclavicular ligaments, which provide stability and prevent excessive movement. These ligaments support shoulder motion, allowing for overhead and lifting movements while maintaining the integrity of the joint. When these ligaments are damaged or ruptured, the joint becomes unstable, leading to pain and difficulty with arm movement.
What You Might Feel – Symptoms (Clinical Presentation)
Patients with AC joint injuries typically experience pain at the top of the shoulder, which worsens with lifting the arm or with activities involving overhead motion. There may also be visible deformity, particularly in severe injuries where the collarbone is displaced. Other symptoms include tenderness over the AC joint, swelling, and a limited range of motion in the shoulder. In more severe cases, a “step-off” deformity may be visible where the clavicle appears raised compared to the acromion.
How Doctors Find the Problem? (Diagnosis and Imaging)
AC joint injuries are diagnosed through a combination of physical examination and imaging studies. Physical tests, such as the cross-body adduction test, can help identify AC joint pain and instability. X-rays are typically used to assess the extent of the injury, particularly to identify displacement of the clavicle. In some cases, CT scans or MRIs are used to assess ligament damage and rule out other associated injuries, such as rotator cuff tears.
Classification
AC joint injuries are classified into six types based on the degree of ligament damage and bone displacement:
- Type I: Mild sprain of the AC ligaments with no displacement.
- Type II: Rupture of the AC ligaments with slight displacement of the clavicle.
- Type III: Complete rupture of both the AC and coracoclavicular ligaments, with significant displacement of the clavicle.
- Type IV: Severe displacement with the clavicle displaced posteriorly into the trapezius muscle.
- Type V: Severe displacement with significant displacement of the clavicle, often involving muscle and skin involvement.
- Type VI: Rare, where the clavicle is displaced inferiorly, beneath the coracoid process.
Other Problems That Can Feel Similar (Differential Diagnosis)
Other conditions that can cause similar symptoms include shoulder impingement syndrome, rotator cuff tears, acromial fractures, and shoulder instability. Differentiating between these conditions requires a thorough clinical examination and imaging studies to pinpoint the exact cause of the shoulder pain.
Treatment Options
Non-Surgical Care
- Rest and activity modification to reduce strain on the AC joint
- Anti-inflammatory medications or corticosteroid injections to manage pain
- Physical therapy to strengthen surrounding muscles and restore function
Surgical Care
- Open AC joint reconstruction: This procedure involves repairing or reconstructing the ligaments around the AC joint using either autografts or allografts, as well as securing the bones in place with a tensioning system, such as FiberTape cerclage.
- Arthroscopic AC joint reconstruction: Minimally invasive approach for joint reconstruction, which offers quicker recovery times and less postoperative discomfort, though it requires more technical skill.
Recovery and What to Expect After Treatment
Recovery from open AC joint reconstruction typically involves wearing a sling for a few weeks to protect the shoulder while healing. Gradual physical therapy is essential for restoring motion, strength, and function. Patients generally return to normal daily activities in about 2 to 3 months, with a full return to sports or labor-intensive activities occurring between 3 to 6 months, depending on recovery progress.
Possible Risks or Side Effects (Complications)
Complications from open AC joint reconstruction may include infection, nerve injury, hardware irritation or migration, fracture of the clavicle, and recurrence of the shoulder deformity. These risks are relatively low with proper surgical technique, but patients should be closely monitored for signs of complications during recovery.
Long-Term Outlook (Prognosis)
The prognosis for patients undergoing open AC joint reconstruction is generally favorable, with most experiencing significant pain relief and improved shoulder function. The technique’s success rates are high, particularly for individuals who do not have pre-existing shoulder instability or significant muscle weakness.
Out-of-Pocket Cost
Medicare
CPT Code 23485 – Open AC Joint Reconstruction (Surgical Repair of Acromioclavicular Joint Separation): $226.15
Medicare Part B typically covers 80% of the approved cost for this procedure 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 usually cover the remaining 20%, minimizing or eliminating out-of-pocket expenses for Medicare-approved surgeries. These plans work alongside Medicare to fill the coverage gap and reduce patient costs.
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 between $100 and $300, depending on your plan and provider network.
Workers’ Compensation
If your AC joint reconstruction 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 AC joint reconstruction is needed due to an automobile accident, No-Fault Insurance will typically cover the full cost of 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
James Thompson required open AC joint reconstruction (CPT 23485) to repair a severe shoulder separation from a sports injury. His estimated Medicare out-of-pocket cost was $226.15. Since James had supplemental insurance through Blue Cross Blue Shield, his remaining balance was fully covered, leaving him with no out-of-pocket expenses for the surgery.
Frequently Asked Questions (FAQ)
Q. What is an open acromioclavicular (AC) joint reconstruction?
A. It is a surgical procedure to repair and stabilize the AC joint, which connects the collarbone (clavicle) to the shoulder blade (acromion), typically after injury or dislocation.
Q. Why might someone need an AC joint reconstruction?
A. This surgery is usually needed after severe AC joint injuries or dislocations that cause pain, instability, or functional limitations.
Q. What causes AC joint injuries?
A. AC joint injuries often result from a direct blow to the shoulder, falls onto the shoulder, or traumatic events during sports or accidents.
Q. What symptoms indicate an AC joint injury?
A. Symptoms include shoulder pain, swelling, tenderness over the AC joint, a visible bump or deformity, and decreased shoulder function.
Q. How is the AC joint reconstruction surgery performed?
A. The surgeon makes an incision over the AC joint, repairs or reconstructs the damaged ligaments, and stabilizes the joint using sutures, grafts, or implants.
Q. What types of grafts might be used in AC joint reconstruction?
A. Grafts can be taken from the patient’s own tissue (autograft) or from a donor (allograft) to reconstruct the ligaments.
Q. What is the goal of the surgery?
A. The goal is to restore joint stability, relieve pain, and improve shoulder function.
Q. How long does the surgery typically take?
A. The procedure usually takes about one to two hours, depending on the complexity.
Q. What is the recovery process after AC joint reconstruction?
A. Recovery involves immobilization in a sling, followed by physical therapy to regain motion and strength over several months.
Q. When can patients expect to return to normal activities?
A. Most patients can return to daily activities within a few weeks, but full recovery and return to sports or heavy lifting may take several months.
Q. Are there risks or complications associated with the surgery?
A. Potential risks include infection, nerve injury, stiffness, hardware irritation, and failure of the reconstruction.
Q. How successful is AC joint reconstruction surgery?
A. Most patients experience significant pain relief and improved shoulder stability and function after surgery.
Q. Is physical therapy necessary after surgery?
A. Yes, physical therapy is essential to restore motion, strength, and function of the shoulder.
Q. What types of injuries are classified as severe enough to require surgery?
A. Severe AC joint separations such as Rockwood types IV, V, and VI typically require surgical reconstruction.
Q. Can the surgery be performed arthroscopically?
A. This page focuses on open reconstruction; however, some cases may be treated arthroscopically depending on surgeon preference and injury type.
Q. What is the expected scar from surgery?
A. The scar is located over the AC joint and usually fades over time but will be permanent.
Q. Is pain management addressed after surgery?
A. Yes, pain management includes medications and careful monitoring during recovery to ensure patient comfort.
Q. What should patients do to prepare for AC joint reconstruction?
A. Patients should discuss their medical history, medications, and expectations with their surgeon and follow preoperative instructions closely.
Q. How is joint stability assessed after surgery?
A. Stability is evaluated during follow-up visits through physical examination and imaging if necessary.
Q. What kind of activities should be avoided immediately after surgery?
A. Patients should avoid lifting heavy objects, overhead activities, and any motion that stresses the AC joint until cleared by their surgeon.
Q. What follow-up care is required after surgery?
A. Follow-up includes wound checks, physical therapy progression, and monitoring for complications.
Summary and Takeaway
Open AC joint reconstruction using the semitendinosus allograft and FiberTape cerclage system is a safe and effective option for chronic AC joint injuries. This technique offers strong, natural-looking results with reduced risk of complications compared to older methods involving plates or screws. When performed in carefully selected patients, the procedure offers restored shoulder function, pain relief, and cosmetic improvement.
Clinical Insight & Recent Findings
Recent studies have shown that open AC joint reconstruction offers superior long-term results for patients with chronic shoulder separations, providing improved stability and function while reducing the need for revision surgeries.
Who Performs This Treatment? (Specialists and Team Involved)
Orthopedic surgeons specializing in shoulder injuries and reconstruction typically perform open AC joint reconstruction. Physical therapists play an integral role in post-surgery rehabilitation.
When to See a Specialist?
Consult a specialist if you experience persistent AC joint pain or instability, especially if conservative treatments have failed or if you have an obvious deformity following an injury.
When to Go to the Emergency Room?
Seek emergency care if you experience severe shoulder pain following a traumatic injury or if you develop signs of infection, such as fever or redness at the surgical site.
What Recovery Really Looks Like?
Recovery involves wearing a sling, followed by physical therapy to restore motion and strength. Most patients can return to daily activities within a couple of months, with full recovery occurring over several months.
What Happens If You Ignore It?
Ignoring a severe AC joint injury can lead to chronic pain, functional limitations, and worsening instability, potentially requiring more invasive treatments in the future.
How to Prevent It?
Prevent AC joint injuries by avoiding direct trauma to the shoulder, strengthening the rotator cuff and surrounding muscles, and using proper technique during physical activities.
Nutrition and Bone or Joint Health
A diet rich in calcium, vitamin D, and omega-3 fatty acids supports joint health and aids in recovery after surgery.
Activity and Lifestyle Modifications
Avoiding excessive overhead lifting or repetitive strain on the shoulder can help prevent future injuries and improve shoulder health.
