AC Joint Repair and Reconstruction
The acromioclavicular joint — or AC joint — is the small but critical connection where the outer end of the collarbone (clavicle) meets the top of the shoulder blade (acromion), stabilized by the AC ligaments and the coracoclavicular (CC) ligaments that anchor the collarbone to the shoulder girdle below. An AC joint injury — commonly called a “separated shoulder,” though it is entirely different from a shoulder dislocation — occurs when a direct blow to the top of the shoulder or a fall onto an outstretched hand tears some or all of the ligaments that hold the joint together, allowing the collarbone to shift out of its normal alignment. AC joint separations are graded from type I (a mild sprain with no visible displacement) through type VI (a severe disruption with the collarbone displaced completely), and the grade of injury determines whether conservative treatment with rest and rehabilitation will be sufficient or whether surgical reconstruction is needed to restore the joint’s anatomy and function.
Dr. Jonathan Glashow is a board-certified orthopedic surgeon and Clinical Associate Professor of Orthopedic Surgery at NYU Grossman School of Medicine, with specialized shoulder training that includes a traveling fellowship under Dr. Charles Rockwood — who developed the widely used classification system for AC joint injuries — and Dr. Richard Hawkins, two of the most influential shoulder surgeons in the field. As Chief Medical Officer for the New Jersey Devils and Philadelphia 76ers, Dr. Glashow manages AC joint separations regularly on the sideline — it is one of the most common acute shoulder injuries in both hockey (from body checks and board contact) and basketball (from falls and collisions). With over 30 years of experience, more than 15,000 orthopedic procedures, and recognition as a Castle Connolly Top Doctor every year since 2000, he evaluates and treats AC joint injuries at his Upper East Side practice in New York City.
AC Joint Injury Grades, Diagnosis, and Treatment
The acromioclavicular (AC) joint is often injured during physical contact sports such as football, soccer, martial arts, wrestling, hockey, and skiing, as well as motorcycle and bicycle accidents. The injury is known most commonly as a “separated shoulder” but is in no way related to a dislocated shoulder — a dislocated shoulder involves a different joint altogether. AC joint injuries are normally caused by a fall on an outstretched hand or a strong force such as a direct tackle.
There are mild and severe AC joint injuries, and each requires a different treatment approach:
- A mild shoulder separation occurs when the AC ligament is sprained but does not displace the collarbone.
- A serious shoulder separation is more intense — the AC ligament tears and the coracoclavicular (CC) ligament sprains or tears slightly, causing misalignment in the collarbone. In the most severe shoulder separation injury, both the AC and CC ligaments are torn and the AC joint is completely displaced.
Diagnosis is straightforward. The examination typically demonstrates tenderness or bruising around the top of the shoulder near the AC joint, and the suspected diagnosis can be confirmed using an X-ray — which compares the injured side with the patient’s other joint. Same-day X-rays are available at Dr. Glashow’s Upper East Side practice.
Shoulder surgery — acromioclavicular reconstruction — is required for cases where the patient continues to have pain or an unacceptable deformity in the joint after several months of conservative treatment, or when the severity of the initial separation warrants surgical intervention. The most common type of surgery for AC joint injury involves restoring the anatomy by repairing or grafting new ligaments and addressing any additional damage to the surrounding structures.
If you have sustained a blow to the top of your shoulder, are experiencing pain and a visible bump at the AC joint, or have been diagnosed with an AC joint separation and want to discuss your treatment options, Dr. Glashow provides same-day evaluation with on-site X-rays at his Upper East Side practice in New York City. Contact our office to schedule your consultation.
Frequently Asked Questions About AC Joint Repair
What is the difference between a separated shoulder and a dislocated shoulder?
A separated shoulder is an injury to the acromioclavicular (AC) joint at the top of the shoulder, where the collarbone meets the shoulder blade. A dislocated shoulder involves the glenohumeral joint — the ball-and-socket joint where the upper arm bone comes out of the shoulder socket. These are two entirely different joints, different injuries, and different treatment approaches. AC joint separations involve torn ligaments at the top of the shoulder and produce a visible bump where the collarbone has shifted. Shoulder dislocations involve the humeral head displacing from the glenoid socket and produce instability, loss of range of motion, and often labral damage.
How are AC joint injuries graded?
AC joint injuries are classified into six grades (types I through VI) based on the severity of ligament damage and the degree of collarbone displacement. Types I and II involve sprains or partial tears of the AC ligaments with minimal displacement and are typically treated conservatively. Type III injuries involve complete tears of both the AC and CC ligaments with moderate collarbone displacement — treatment may be conservative or surgical depending on the patient’s activity demands and symptoms. Types IV, V, and VI involve severe displacement of the collarbone and nearly always require surgical reconstruction. Dr. Glashow evaluates the grade using clinical examination and X-rays to determine the most appropriate treatment approach.
Can an AC joint separation heal without surgery?
Yes — most type I and type II AC joint separations heal well with conservative treatment including a sling for comfort, ice, anti-inflammatory medications, and a physical therapy program that progressively restores range of motion and strengthening. Many type III injuries also respond to non-operative management, particularly in patients who are not high-demand overhead athletes. However, type III injuries that remain symptomatic after several months of conservative treatment, and all type IV through VI injuries, typically require surgical reconstruction to restore normal anatomy and function. Dr. Glashow takes a conservative-first approach for lower-grade injuries and recommends surgery only when the clinical situation warrants it.
What does AC joint surgery involve?
AC joint reconstruction typically involves repairing or reconstructing the torn coracoclavicular (CC) ligaments — the primary vertical stabilizers of the collarbone — to restore the normal relationship between the clavicle and the shoulder blade. Dr. Glashow may use a tendon graft, synthetic augmentation, or direct ligament repair depending on the injury pattern and the timing of surgery relative to the initial injury. In some cases, the distal end of the clavicle is trimmed (distal clavicle excision) to eliminate painful bone-on-bone contact. The procedure is performed through a small incision at the top of the shoulder.
How long does recovery take after AC joint surgery?
Patients typically wear a sling for four to six weeks after surgery to protect the reconstructed ligaments while they heal. Gentle range-of-motion exercises begin within the first few weeks, with progressive strengthening introduced over the following months. Most patients return to daily activities within six to eight weeks and to full sports or physically demanding work within four to six months, depending on the sport and the demands placed on the shoulder. Dr. Glashow coordinates rehabilitation closely with physical therapists and uses clinical and imaging milestones — not just a calendar timeline — to guide each patient’s return to activity.
Will I have a permanent bump on my shoulder after an AC joint separation?
In lower-grade injuries treated conservatively, a small, visible bump at the top of the shoulder — where the collarbone sits slightly higher than normal — may remain permanently. This bump is usually painless once the ligaments have healed and is cosmetic rather than functional. In higher-grade separations treated with surgical reconstruction, the goal of surgery is to restore the collarbone to its normal position, which typically eliminates or significantly reduces the visible deformity.
