Understanding Acromioclavicular (AC) Joint Repairs: Restoring Shoulder Stability

The shoulder is a complex structure, allowing for an incredible range of motion. However, this mobility can sometimes come at the cost of stability. One common injury affecting the shoulder complex involves the acromioclavicular (AC) joint, the point where the collarbone (clavicle) meets the highest point of the shoulder blade (acromion). An injury here, often called a shoulder separation or AC joint separation, can range from a mild sprain to a complete tear of the supporting ligaments, leading to significant pain and instability. When conservative treatments aren’t enough, Acromioclavicular (AC) joint repairs or reconstruction surgery may be necessary to restore function and alleviate pain.

This article dives into AC joint injuries, the types of surgical interventions available, and what to expect during recovery.

What is the AC Joint and How Does it Get Injured?

The AC joint plays a crucial role in shoulder movement and stability. It’s held together primarily by the acromioclavicular ligaments (which directly connect the acromion and clavicle) and the coracoclavicular (CC) ligaments (which connect the clavicle to a bony projection on the shoulder blade called the coracoid process).

AC joint injuries typically occur due to:

  • Direct falls onto the shoulder: This is the most common cause, often seen in contact sports like rugby or cycling accidents.
  • Falling onto an outstretched hand: The force travels up the arm to the shoulder.
  • Direct blow to the shoulder: Less common, but can occur in collisions.

The severity of an AC joint injury is graded based on the extent of ligament damage and the displacement of the clavicle:

  • Grade I: A mild sprain of the AC ligaments with no significant displacement. The CC ligaments are intact.
  • Grade II: A tear of the AC ligaments with a sprain or partial tear of the CC ligaments. There’s slight displacement of the clavicle.
  • Grade III: Complete tears of both the AC and CC ligaments, resulting in noticeable upward displacement of the clavicle, creating a visible bump on the shoulder.
  • Grades IV, V, and VI: These are less common and involve more severe displacement of the clavicle (posteriorly, superiorly by a large amount, or inferiorly).

Symptoms often include shoulder pain (especially on top of the shoulder), swelling, bruising, limited range of motion, and potentially a visible deformity or bump if the clavicle is significantly displaced.

When is Surgery Needed? AC Joint Repair vs. Conservative Treatment

The decision between conservative treatment and AC joint surgery depends largely on the severity (grade) of the injury, the patient’s activity level, occupation, and symptoms like persistent pain or instability.

  • Non-operative Treatment: Grade I and most Grade II injuries usually respond well to conservative management. This typically involves:

    • Rest and activity modification
    • Ice application
    • Pain relief medication (NSAIDs)
    • Immobilisation in a sling for comfort (usually 1-3 weeks)
    • Physical therapy to restore range of motion and strength.
    • For Grade III injuries, non-operative treatment is often successful, although a persistent bump may remain. However, some individuals, especially high-demand athletes or manual labourers, may experience ongoing pain or functional limitations.

  • Surgical Treatment: AC joint surgery is typically considered for:

    • Most Grade IV, V, and VI injuries.
    • Grade III injuries in specific patient groups (e.g., high-level athletes, heavy labourers) or those who fail conservative treatment and experience chronic AC joint instability, pain, or weakness.
    • Acute injuries (ideally within 2-3 weeks) often undergo primary acromioclavicular joint repair.
    • Chronic injuries (often those presenting months or years later) may require AC joint reconstruction.

The goal of AC joint stabilization surgery is to realign the joint and repair or reconstruct the torn ligaments to restore stability and function.

Surgical Techniques for AC Joint Repair and Reconstruction

Several surgical procedure options exist for treating severe AC joint separations. The choice often depends on whether the injury is acute or chronic, the surgeon’s preference, and the specific patient factors.

  1. Acute Arthroscopic AC Joint Repair:

    • Often preferred for injuries treated within a few weeks.
    • This is a minimally invasive (keyhole surgery) approach.
    • The surgeon uses small incisions and a camera (arthroscope) to visualize the joint.
    • Strong, suture-like materials (fiber-tapes) are passed around the coracoid process and through tunnels drilled in the clavicle.
    • These tapes are secured with small metal (titanium buttons) or endobuttons on the bone surface, pulling the clavicle down into its correct position and holding it while the ligaments heal.
    • Sometimes combined with a mini-open incision over the collarbone.

  2. AC Joint Reconstruction (for Chronic Instability):

    • Used for older injuries where the ligaments haven’t healed or direct repair isn’t feasible.
    • These procedures aim to rebuild the coracoclavicular ligaments using a graft.
    • Graft Sources: Can be an autograft (using one of the patient’s own tendons), an allograft (using donor tendon tissue), or a synthetic ligament like a LARS ligament (Ligament Augmentation and Reconstruction System).
    • Modified Weaver-Dunn Procedure: A traditional open technique where the coracoacromial (CA) ligament is transferred to the end of the clavicle to substitute for the torn CC ligaments. Often combined with graft augmentation or suture/tape fixation.
    • Anatomic Reconstruction: Techniques aim to replicate the native anatomy of the CC ligaments using grafts passed through bone tunnels in the clavicle and coracoid process, often secured with screws or buttons.

  3. Hardware Fixation (Less Common Now):

    • Historically, screws or plates were used to hold the clavicle reduced relative to the coracoid or acromion.
    • Often required a second surgery for hardware removal.
    • Wiring techniques have also been used.
    • These methods are less favoured now due to higher complication rates (hardware failure, irritation) compared to modern tape/button or reconstruction techniques.

  4. Distal Clavicle Excision (Resection Arthroplasty):

    • Sometimes performed, often in conjunction with other procedures or for AC joint arthritis.
    • Involves removing a small portion of the end of the clavicle to prevent painful bone-on-bone contact with the acromion.

Recovery and Rehabilitation After AC Joint Surgery

Recovery after acromioclavicular joint repair or reconstruction is crucial for a successful outcome. It requires patience and commitment to a structured rehabilitation program.

  • Immobilisation: Your arm will be placed in a sling immediately after surgery, typically worn for 4-6 weeks to protect the repair/reconstruction. You may be allowed to remove it for gentle, controlled exercises as advised by your surgeon or therapist.
  • Pain Management: Pain relief medication will be prescribed to manage discomfort in the initial post-operative period. Ice packs can also help reduce pain and swelling.
  • Wound Care: Instructions will be provided on how to care for your incisions to prevent infection.
  • Physiotherapy: This is essential and usually starts within the first few weeks post-surgery, initially focusing on gentle passive and active-assisted range of motion exercises for the elbow, wrist, hand, and eventually the shoulder, as guided by your therapist and surgeon’s protocol.
  • Strengthening: As healing progresses (usually after 6-8 weeks), exercises to strengthen the rotator cuff and muscles around the shoulder blade will be introduced.
  • Return to Activity:
    • Light activities and desk work: Often possible within a few weeks.
    • Driving: Usually permitted around 6-8 weeks once out of the sling and comfortable.
    • Heavier lifting/manual labour: May take 3-6 months.
    • Return to sports: Highly variable, often taking 4-6 months or longer, depending on the sport and individual progress. Contact sports typically require the longest recovery.

Potential Complications: While AC joint surgery is generally safe and effective, potential risks include infection, stiffness (frozen shoulder), nerve injury, hardware failure or irritation, recurrent instability, persistent pain, and complications related to anaesthesia.

Key Takeaways

  • AC joint injuries (shoulder separations) result from damage to the ligaments connecting the clavicle and acromion/coracoid process.
  • Severity is graded (I-VI), influencing treatment decisions.
  • Grades I-II and many Grade III injuries are managed non-operatively with rest, ice, sling use, and physiotherapy.
  • Surgery (AC joint repair or reconstruction) is considered for higher-grade injuries or failed conservative treatment, especially in active individuals.
  • Surgical techniques include arthroscopic AC joint repair with fiber-tapes and buttons, or reconstruction using grafts (LARS ligament, tendon grafts).
  • Recovery involves sling immobilisation followed by a progressive physiotherapy program lasting several months.

If you’re suffering from shoulder pain or instability following an injury, seeking expert assessment is crucial. Understanding the nature of your AC joint injury and the available treatment options is the first step towards recovery.

Ready to discuss your shoulder concerns?