AC Joint Arthritis: Surgical Treatment, Recovery, and Risks

What is the surgical treatment for AC joint arthritis?

Surgical treatment for acromioclavicular (AC) joint arthritis primarily involves distal clavicle excision, also known as the Mumford procedure, which aims to alleviate pain by removing a small portion of the clavicle to prevent bone-on-bone friction. In rare cases, more complex reconstructions or fusions may be considered.

Understanding AC Joint Arthritis

The acromioclavicular (AC) joint is a small but critical joint located at the top of the shoulder, where the clavicle (collarbone) meets the acromion, a part of the shoulder blade (scapula). Like other joints in the body, it is susceptible to arthritis, a condition characterized by the breakdown of articular cartilage, leading to pain, stiffness, and reduced range of motion.

• Anatomy of the AC Joint: The AC joint is a diarthrodial joint, meaning it has a joint capsule, synovial fluid, and articular cartilage covering the ends of the bones. It allows for subtle movements that facilitate the full range of motion of the shoulder blade and arm. Ligaments, such as the acromioclavicular ligaments and the coracoclavicular ligaments (conoid and trapezoid), provide stability to the joint.
• Causes and Symptoms: AC joint arthritis commonly results from chronic wear and tear, repetitive overhead activities (common in athletes like weightlifters, throwers, and swimmers), or previous trauma, such as an AC joint separation. Symptoms typically include localized pain at the top of the shoulder, often radiating into the neck or arm, tenderness to the touch, clicking or grinding sensations, and pain with overhead movements or activities that involve reaching across the body.
• Non-Surgical Management: Initial treatment for AC joint arthritis is almost always conservative. This includes rest, activity modification, anti-inflammatory medications (NSAIDs), ice application, physical therapy to improve shoulder mechanics and strength, and corticosteroid injections into the joint to reduce inflammation and pain.

When is Surgery Considered?

Surgery for AC joint arthritis is generally reserved for individuals who have exhausted non-surgical treatment options without significant relief from their symptoms. It is a decision typically made collaboratively between the patient and their orthopedic surgeon.

• Failure of Conservative Treatment: The primary indication for surgery is persistent and debilitating pain that has not responded to a comprehensive course of conservative management over several months.
• Persistent Pain and Functional Limitation: When pain significantly interferes with daily activities, work, sleep, or participation in sports and exercise, despite non-surgical interventions, surgery may be considered to restore function and improve quality of life.
• Severity of Arthritis: Radiographic evidence of significant AC joint degeneration, such as severe joint space narrowing, bone spurs (osteophytes), and subchondral cysts, can support the decision for surgical intervention, especially when correlated with clinical symptoms.

Primary Surgical Procedure: Distal Clavicle Excision (Mumford Procedure)

The most common surgical procedure for AC joint arthritis is the distal clavicle excision, often referred to as the Mumford procedure after its originator.

• Procedure Overview: This procedure involves removing a small segment (typically 5-10 millimeters) from the lateral (outer) end of the clavicle. The goal is to create a space between the end of the clavicle and the acromion, preventing the arthritic bone surfaces from rubbing against each other and causing pain. The space created fills with scar tissue, forming a pseudoarthrosis (a false joint) that allows for pain-free movement.
• Arthroscopic vs. Open Technique:
  • Arthroscopic Distal Clavicle Excision: This minimally invasive approach is performed using a small camera (arthroscope) and specialized instruments inserted through tiny incisions. It typically results in less pain, smaller scars, and potentially faster initial recovery compared to open surgery. It is the preferred method for many surgeons.
  • Open Distal Clavicle Excision: This involves a larger incision directly over the AC joint. While more invasive, it allows the surgeon a direct view of the joint and may be preferred in cases with significant bone spurs, previous surgeries, or when other procedures are performed concurrently.
• Mechanism of Action: By removing the arthritic bone ends, the procedure eliminates the source of the bone-on-bone friction and inflammation that causes pain. The new fibrous tissue that forms in the excised space acts as a cushion, allowing for smooth, pain-free movement.
• Potential Benefits: Patients often experience significant reduction or elimination of AC joint pain, improved range of motion, and enhanced ability to perform daily activities and return to sports.

Other Surgical Considerations and Procedures

While distal clavicle excision is the mainstay, other procedures may be considered in specific, less common scenarios, or as adjunctive treatments.

• AC Joint Arthrodesis (Fusion): This is a rare procedure for AC joint arthritis, typically reserved for cases of severe, intractable pain where other treatments have failed, especially if there's significant instability. It involves fusing the clavicle directly to the acromion, eliminating all motion at the joint. While it eliminates pain from the joint, it also eliminates motion, which can impact overall shoulder mechanics.
• AC Joint Reconstruction: In cases where severe arthritis is accompanied by significant instability (e.g., from a chronic AC joint separation that also developed arthritis), a reconstruction of the AC joint ligaments might be considered in conjunction with a distal clavicle excision. This aims to restore stability while addressing the arthritic pain.

Post-Surgical Rehabilitation and Recovery

Rehabilitation is a critical component of successful surgical outcomes for AC joint arthritis. A structured physical therapy program is essential to restore strength, flexibility, and function.

• Immediate Post-Op: Patients typically wear a sling for a short period (e.g., 1-2 weeks) for comfort and protection. Pain management, including oral pain medications and ice, is crucial.
• Phased Rehabilitation:
  • Phase 1 (Early Recovery): Focuses on pain and swelling control, gentle passive and assisted range of motion exercises to prevent stiffness.
  • Phase 2 (Intermediate): Progresses to active range of motion, light strengthening exercises for the rotator cuff and periscapular muscles, and gradual return to light daily activities.
  • Phase 3 (Advanced): Concentrates on progressive strengthening, endurance training, proprioception, and sport-specific or activity-specific drills.
• Expected Recovery Timeline: Full recovery varies but typically ranges from 6 weeks to 3-6 months. Return to heavy lifting, overhead sports, or demanding physical activities can take 3-6 months or longer, depending on the individual's progress and the demands of their activity.

Potential Risks and Complications

As with any surgical procedure, distal clavicle excision carries potential risks, though serious complications are uncommon.

• General Surgical Risks: These include infection, excessive bleeding, adverse reaction to anesthesia, and blood clots.
• Specific AC Joint Risks:
  • Persistent Pain: While the goal is pain relief, some patients may experience ongoing discomfort, though typically less severe than pre-surgery.
  • Stiffness: Adhesions or inadequate rehabilitation can lead to shoulder stiffness.
  • Instability: Rarely, the removal of too much bone can lead to mild instability, though this is uncommon with appropriate surgical technique.
  • Nerve Damage: Injury to superficial nerves can cause numbness or altered sensation around the incision site.
  • Failure to Improve: In some cases, symptoms may not significantly improve, necessitating further investigation.

Conclusion

Surgical treatment for AC joint arthritis, primarily through distal clavicle excision, offers a reliable solution for individuals experiencing persistent and debilitating pain unresponsive to conservative measures. Understanding the procedure, the recovery process, and potential risks is vital for informed decision-making. With appropriate surgical technique and dedicated rehabilitation, patients can often achieve significant pain relief and a return to their desired activities, underscoring the importance of a collaborative approach between the patient, surgeon, and physical therapist.