Acromioclavicular (AC) Joint Repair

Overview

Acromioclavicular (AC) joint injuries are commonly seen in active individuals, particularly athletes and manual laborers. The AC joint connects the collarbone (clavicle) to the highest point of the shoulder blade (acromion), and it plays a crucial role in shoulder stability and movement. Injury to this joint, ranging from mild sprains to complete dislocations, can significantly impair shoulder function and cause persistent pain.

Management of AC joint injuries depends on the severity, typically classified using the Rockwood scale (Types I–VI). While mild injuries (Types I and II) often respond well to conservative treatment, high-grade dislocations (Types III–VI) frequently require surgical reconstruction.

Timing of Surgery: Early vs. Delayed Repair

Historically, early surgical intervention—ideally within two weeks of injury—was believed to yield superior outcomes. However, a 2020 study published in the Journal of Shoulder and Elbow Surgery examined outcomes from both early (within 2 weeks) and delayed (beyond 2 weeks) surgical repairs and found no significant difference in long-term results when a modern, anatomic technique was used.

Key Findings:

• Both early and delayed surgeries provided excellent functional outcomes.
• Objective scores such as the ACJI (Acromioclavicular Joint Instability), Taft, and Subjective Shoulder Value (SSV) were comparable between the two groups.
• Pain levels, measured using the Visual Analog Scale (VAS), and patient satisfaction were similarly high regardless of surgery timing.
• The use of combined coracoclavicular (CC) and AC joint ligament reconstruction contributed significantly to success rates.

Surgical Technique: Anatomic Reconstruction

Two main studies illustrate the evolution of surgical approaches. In the prospective pilot study from India, surgeons developed a cost-effective anatomic reconstruction technique using synthetic sutures, Endobuttons, and temporary K-wire augmentation.

Surgical Steps:

1. Incision and Exposure: A 5-cm saber-cut incision is made to expose the distal clavicle, AC joint, and base of the coracoid.
2. Coracoclavicular Reconstruction:
   • A tunnel is drilled through the coracoid.
   • A titanium Endobutton loaded with synthetic fiber wires is passed and flipped beneath the coracoid for secure anchorage.
   • Matching drill holes are made in the clavicle, and the wires are tied over a two-holed reconstruction plate, mimicking the natural positions of the conoid and trapezoid ligaments.
3. AC Joint Stabilization:
   • The torn AC ligaments are either repaired directly or reinforced using sutures.
   • Temporary K-wires are passed across the AC joint to maintain position until healing occurs.
4. Rehabilitation:
   • Sling immobilization is maintained for 3 weeks.
   • Passive range of motion exercises begin at week 2.
   • K-wires are removed after 3 weeks, and strengthening exercises commence by 12 weeks.

This method emphasizes restoring both vertical and anteroposterior stability, essential for pain-free function.

Biomechanics and Anatomical Rationale

Understanding the stabilizing structures of the AC joint is crucial:

• AC Ligaments resist anterior-posterior translation and are vital for horizontal stability.
• CC Ligaments, consisting of the conoid and trapezoid components, prevent vertical displacement:
  • The conoid ligament is situated more medially and posteriorly.
  • The trapezoid ligament is positioned more laterally and anteriorly.
• Reconstruction techniques aim to replicate these anatomical positions to restore native shoulder kinematics.

Advantages of the Described Techniques

• Cost-effective: The technique uses widely available synthetic sutures and plates, reducing dependency on expensive implants like suture anchors and allografts.
• Short learning curve: Compared to all-arthroscopic methods, this open technique is more reproducible for surgeons without advanced arthroscopy training.
• Versatile timing: Successful even in delayed presentations due to the use of biologic grafts or strong synthetic substitutes.
• Minimal complications: The risk of implant failure, infection, and soft tissue injury remains low.

Conclusion

Modern anatomic reconstruction of the AC joint using combined AC and CC ligament repair offers durable, functionally excellent outcomes—even in delayed surgical cases. These techniques restore biomechanical integrity, reduce postoperative pain, and are accessible to a wide range of orthopedic practices. As surgical tools and techniques evolve, patients can expect continued improvements in both cosmetic and functional joint.

 

Do you have more questions?

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.