AC Joint Resection

The acromioclavicular (AC) joint plays a critical role in shoulder mobility and function. When this joint becomes arthritic or painful—often due to trauma, overuse, or degeneration—patients may experience significant discomfort with everyday tasks or sports. When conservative treatments fail, surgical resection of the distal clavicle is often performed. Traditionally done via an open approach, a less invasive method known as arthroscopic AC joint resection has emerged, offering equivalent outcomes with less tissue disruption and faster recovery.

When Is Surgery Needed?

Patients typically undergo surgery when they experience:

• Persistent pain localized at the AC joint
• Discomfort with overhead motion, weightlifting, or cross-body movements
• Tenderness on palpation over the joint
• Failure to respond to 6+ months of conservative care (e.g., NSAIDs, physical therapy, steroid injections)

 

What Is Arthroscopic AC Joint Resection?

Arthroscopic resection involves removing the damaged portion of the distal clavicle using small instruments inserted through keyhole incisions. The surgeon carefully eliminates:

• Degenerated articular cartilage
• Inflamed synovial tissue
• Osteophytes (bone spurs)
• The joint disc if torn or fragmented

Unlike the open procedure, which requires detaching the deltoid muscle, the arthroscopic technique preserves key stabilizing structures like the deltoid-trapezoid fascia and superior AC ligament, reducing the risk of postoperative weakness.

Surgical Technique: Step-by-Step

1. Patient Positioning
Patients are placed in either lateral decubitus or beach chair position under anesthesia.

2. Portal Creation & Visualization

• A posterior portal is used to access the subacromial space.
• Anterior and lateral portals are created for instruments and fluid inflow.

3. Joint Identification & Debridement

• A spinal needle helps identify the AC joint under arthroscopy.
• Synovial resection clears inflamed tissues.
• Bone spurs and degenerative tissue are removed from the lateral clavicle and medial acromion.

4. Bone Resection

• Approximately 10–15 mm of the distal clavicle is resected.
• In some cases, 5 mm of the medial acromion is also removed to prevent impingement.

5. Final Check
The surgeon confirms no bone contact remains during shoulder motion—even during cross-body movements.

Imaging and Diagnosis

Before surgery, imaging may include:

• X-rays to assess joint space narrowing or osteophytes
• MRI to detect joint fluid or bone marrow edema
• Bone scans showing increased uptake in symptomatic joints
• Ultrasound to evaluate capsule swelling or osteophytes

Diagnostic injections into the AC joint can confirm pain origin, often used to distinguish AC pathology from subacromial impingement.

Outcomes

In a cohort of 51 patients, the average functional score improved significantly from 67.8 preoperatively to 93.3 postoperatively (out of 100). Most patients returned to normal activity, including sports. Patient satisfaction was high, with 86% stating they would undergo the procedure again.

Notable improvements included:

• Pain reduction
• Increased shoulder motion
• Better function during daily tasks

Advantages of Arthroscopy

Compared to the traditional open Mumford procedure, arthroscopic resection offers:

• Smaller incisions and less soft tissue trauma
• Preservation of muscle and fascia attachments
• Lower risk of postoperative weakness
• Faster rehabilitation

In cadaver studies, arthroscopic bone resection was just as precise and complete as open resection, averaging 14.7 mm in total resected bone compared to 14.8 mm with open surgery.

Rehabilitation

• Day 1: Patients begin active and passive motion exercises.
• Weeks 1–6: Strengthening of rotator cuff and deltoid; overhead activities are avoided.
• Post-6 Weeks: Gradual return to full activities and sports.

Most patients resume full activity within 3–6 months.

Risks and Complications

Complications are rare but may include:

• Superficial wound drainage (resolved with antibiotics)
• Persistent pain in rare cases
• Insufficient resection requiring revision surgery

Importantly, no neurovascular injuries or major complications were observed in the series analyzed.

Final Thoughts

Arthroscopic AC joint resection is a safe, reliable, and minimally invasive alternative to traditional open surgery for AC joint arthritis. It offers significant pain relief, functional recovery, and high patient satisfaction while preserving the joint’s stabilizing anatomy.

 

Do you have more questions?

Q. What is the acromioclavicular (AC) joint and why is it important?

A. The AC joint is where the clavicle (collarbone) meets the acromion (part of the shoulder blade). It plays a critical role in shoulder mobility and function.

Q. What causes AC joint pain or arthritis?

A. AC joint pain or arthritis can result from trauma, overuse, or degeneration, leading to discomfort during everyday tasks or sports activities.

Q. When is AC joint resection surgery recommended?

A. Surgery is typically recommended when patients experience persistent AC joint pain, discomfort with overhead motion, weightlifting, or cross-body movements, tenderness over the joint, and failure to respond to over six months of conservative care.

Q. What is arthroscopic AC joint resection?

A. Arthroscopic AC joint resection is a minimally invasive procedure that removes the damaged portion of the distal clavicle using small instruments inserted through keyhole incisions.

Q. How does arthroscopic resection differ from open surgery?

A. Unlike open surgery, arthroscopic resection preserves key stabilizing structures like the deltoid-trapezoid fascia and superior AC ligament, reducing the risk of postoperative weakness.

Q. What are the steps involved in the arthroscopic AC joint resection procedure?

A. The procedure involves patient positioning, portal creation and visualization, joint identification and debridement, bone resection of approximately 10–15 mm of the distal clavicle, and a final check to ensure no bone contact remains during shoulder motion.

Q. What imaging techniques are used before surgery?

A. Imaging may include X-rays to assess joint space narrowing or osteophytes, MRI to detect joint fluid or bone marrow edema, bone scans showing increased uptake in symptomatic joints, and ultrasound to evaluate capsule swelling or osteophytes.

Q. How is the source of shoulder pain confirmed before surgery?

A. Diagnostic injections into the AC joint can confirm the pain origin and help distinguish AC pathology from subacromial impingement.

Q. What are the expected outcomes after arthroscopic AC joint resection?

A. Patients can expect significant pain reduction, increased shoulder motion, and improved function during daily tasks.

Q. What are the advantages of arthroscopic AC joint resection over open surgery?

A. Arthroscopic resection offers less tissue disruption, faster recovery, and preservation of important stabilizing structures compared to the traditional open Mumford procedure.