Acromioclavicular (AC) Joint Sprain: Overview and Evidence Summary

Condition Overview

An acromioclavicular (AC) joint sprain refers to an injury involving the ligaments that stabilize the AC joint—the small but critical junction between the clavicle and the acromion of the scapula. Although small in size, the AC joint plays a pivotal role in normal shoulder movement, allowing subtle adjustments that support overhead elevation and cross-body motion. When the joint is disrupted, even minor injuries can cause significant discomfort and functional limitation.

AC joint sprains typically result from a fall directly onto the shoulder, such as in cycling, skiing, football, or contact sports. They may also occur during lifting accidents or sudden traction forces to the arm. Patients often describe immediate pain on the top of the shoulder, swelling, and difficulty lifting the arm or reaching across the body. Depending on severity, a visible bump may appear at the joint due to ligament disruption and clavicle elevation.

These sprains are classified into types (I through VI) based on the extent of ligament damage and the displacement of the clavicle. Most AC joint sprains—especially Types I and II—heal very well with conservative care. Higher-grade injuries may require orthopedic evaluation but still often respond well to structured rehabilitation.

Summary of Current Evidence for AC Joint Sprains

Evidence-Based Management Discussion

Understanding the Injury

The AC joint is supported by the acromioclavicular ligaments, coracoclavicular ligaments (trapezoid and conoid), and surrounding soft tissue. Injury severity depends on the extent of disruption to these structures. In lower-grade sprains, the ligaments are stretched or partially torn but maintain stability. In higher-grade injuries, particularly Types III and above, more significant displacement occurs due to coracoclavicular ligament disruption.

A key consideration is that AC joint pain is often exacerbated by cross-body movements, overhead elevation, and heavy lifting. These motions place stress on the joint capsule and surrounding ligaments. Early management aims to protect the joint while allowing enough motion to prevent stiffness and promote recovery.

Exercise Therapy

Rehabilitation should proceed in a progressive manner:

• Acute phase:
  Short-term sling use may reduce pain for Types I and II injuries. Early pendulum exercises and gentle range of motion prevent stiffness.

• Subacute phase:
  Focus shifts to restoring scapular control, improving rotator cuff strength, and re-establishing comfortable overhead movement. Scapular stabilization is particularly important, as dysfunction can increase AC joint stress.

• Return-to-function phase:
  Progressive resistance training, overhead strengthening, closed-chain exercises, and sport- or work-specific tasks are introduced. For athletes, gradual reintroduction of contact or overhead loading is essential.

Most low- and mid-grade sprains recover well within weeks to a few months with structured rehabilitation.

Manual Therapy

Manual techniques may address soft tissue tightness along the upper trapezius, levator scapulae, deltoid, and pectoral region. Improving thoracic mobility can also help normalize shoulder mechanics. Although manual therapy does not repair ligament damage, it can improve comfort and movement, enabling more effective participation in active rehabilitation.

Medications and Injections

NSAIDs may help reduce acute swelling and pain. Corticosteroid injections are more often used in chronic AC joint irritation, osteolysis, or arthrosis—not typically in the early phase of traumatic sprains.

Surgical Considerations

Surgery is generally reserved for:

• Type IV–VI sprains

• Type III injuries in high-level athletes or individuals whose work demands significant overhead or heavy lifting

• Chronic pain or instability despite comprehensive conservative care

Surgical techniques include ligament reconstruction, clavicle stabilization, or AC joint re-alignment procedures. Outcomes are typically good, but surgery is not routinely required for most injuries.

References

Rockwood, C., et al. “Classification and Treatment of AC Joint Injuries.” The Shoulder, 4th ed.

Mazzocca, A., et al. “Biomechanics and Management of Acromioclavicular Joint Injuries.” American Journal of Sports Medicine, 2007.

Beitzel, K., et al. “AC Joint Injuries in Athletes: Treatment and Rehabilitation Perspectives.” Orthopaedic Journal of Sports Medicine, 2014.

Cho, C., et al. “Nonoperative Management of AC Joint Injuries: Outcomes and Predictors of Success.” Journal of Shoulder and Elbow Surgery, 2017.

Struhl, S., et al. “Surgical Reconstruction for Chronic AC Joint Instability.” Clinical Orthopaedics and Related Research, 2018.

Disclaimer

The information in this article is intended for educational purposes and is designed for qualified massage therapists, manual therapists, and rehabilitation professionals. It is not a substitute for medical advice, diagnosis, or treatment. Practitioners must work within their legal scope of practice and regional regulations. Hands-on techniques should only be performed by appropriately trained and licensed individuals. Niel Asher Education is not responsible for any injury, loss, or damage resulting from the use of this content.