AC Joint Injury Rehab | Recovery Timeline & Treatment Guide

The acromioclavicular (AC) joint sits at the top of the shoulder, connecting the acromion (part of the shoulder blade) to the clavicle (collarbone). Although small, this joint plays a major role in transferring load from the arm to the trunk — particularly during lifting, pushing and overhead movement.

Because of this load-transfer role, the AC joint absorbs significant force during falls, collisions and repetitive overhead activity.

AC joint injuries are common in contact sports, overhead athletes, cyclists and even during simple everyday falls.

Most Common Mechanisms of AC Joint Injury

AC joint injuries most often occur from:

Falling directly onto the point of the shoulder (common in football, rugby, cycling and skiing)

A direct blow during contact sport

Landing on an outstretched arm

Heavy or repetitive overhead lifting

Repetitive overhead sport (e.g. tennis, volleyball, CrossFit)

The severity of injury depends on the force of impact and the position of the shoulder at the time.

Proper rehabilitation is essential to restore strength, mobility and shoulder control, and to reduce the risk of reinjury.

Most Common Mechanisms of AC Joint Injury

What Is an AC Joint Injury?

An AC joint injury occurs when the ligaments that stabilise the joint are overstretched or torn, usually following a direct impact to the shoulder or force across the body.

Physiotherapists classify AC joint injuries using the Rockwood classification, which guides management decisions and recovery timelines.

AC Joint Injury Grades (Rockwood Classification)

Commonly Seen Grades:

Grade I:
Mild sprain or stretching of the AC ligaments (no visible separation).

Grade II:
Partial tear with mild joint instability.

Grade III:
Complete rupture of the AC ligaments with visible separation.

These three grades account for the majority of AC joint injuries seen in clinic.

Less Common, Higher-Grade Injuries:

Grade IV:
Clavicle displaced backwards into surrounding tissue.

Grade V:
Significant upward displacement with major ligament disruption.

Grade VI:
Rare injury where the clavicle is displaced downward.

Grades IV–VI are uncommon and typically require orthopaedic review. Surgical management is more frequently considered due to the degree of structural disruption.

Why AC Joint Rehabilitation Matters

After an AC joint injury, the muscles around the shoulder often weaken and movement patterns change. Without a structured rehabilitation program, muscle imbalances and persistent instability can increase the risk of ongoing pain — particularly when returning to sport or heavy overhead tasks.

Rehabilitation introduces the right amount of load at the right time to:

Promote tissue healing

Restore strength and range of motion

Rebuild shoulder stability

Optimise neuromuscular control

Phases of AC Joint Rehabilitation

A structured approach ensures safe and progressive recovery.

1. Acute Phase (Early Protection)

Goals:

Reduce pain and inflammation

Protect the AC joint

Maintain pain-free movement

Management:

Activity modification (avoid heavy lifting and cross-body movements)

Short-term sling use (if required)

Ice for symptom relief

Gentle range-of-motion exercises within pain-free limits

Example Exercises:

Pendulum shoulder swings

Assisted shoulder flexion and abduction

2. Intermediate Phase (Restore Motion & Strength)

Goals:

Reduce pain and inflammation

Protect the AC joint

Maintain pain-free movement

Management:

Activity modification (avoid heavy lifting and cross-body movements)

Short-term sling use (if required)

Ice for symptom relief

Gentle range-of-motion exercises within pain-free limits

Example Progressions:

Pendulum shoulder swings

Assisted shoulder flexion and abduction

2. Intermediate Phase (Restore Motion & Strength)

3. Strength & Functional Control Phase

Goals:

Build strength, power and dynamic stability

Prepare for return to work or sport

Improve neuromuscular control under load

Management:

Progressive resistance training

Closed-chain shoulder work

Controlled plyometric drills (when appropriate)

Gradual exposure to sport-specific movements

Example Activities:

Dumbbell and barbell strengthening

Controlled plyometric throws and catches

Upper limb perturbation drills

Overhead strength progressions

When Am I Ready to Return to Sport?

Returning to sport isn’t based purely on time, it’s based on meeting specific functional criteria.

Your physiotherapist may assess:

Full pain-free range of motion

Symmetrical upper limb strength

Ability to perform overhead movements without compensation

Functional strength testing (e.g. push-up capacity, resisted cross-body movements)

Sport-specific loading drills

For contact athletes, we also consider:

Confidence during impact simulation

Protective taping strategies

Shoulder padding modifications where appropriate

Functional strength testing (e.g. push-up capacity, resisted cross-body movements)

Sport-specific loading drills

A gradual return-to-sport plan is critical to avoid reinjury during the vulnerable reloading phase.

AC Joint Injury Recovery Time

Recovery depends on injury severity and individual healing response:

Grade I: 1–4 weeks

Grade II: 4–8 weeks

Grade III: 8–12+ weeks

Higher-grade or surgical cases: Often longer

These timeframes reflect tissue healing, not necessarily full functional recovery. Progression should be guided by strength, control and symptom response, not just calendar weeks.

Tips for a Successful Recovery

Progress gradually and respect pain signals

Avoid sharp or worsening pain during exercises

Prioritise consistency over intensity

Maintain overall conditioning where possible

Early Assessment Matters

Early physiotherapy assessment can significantly influence recovery outcomes.

Accurate injury grading, appropriate early load management and a structured rehabilitation plan help prevent prolonged pain, weakness and recurrent instability.

Waiting for symptoms to “settle on their own” can delay recovery and lead to compensatory movement patterns.

If you suspect an AC joint injury, early professional guidance ensures you’re on the right path, whether your goal is returning to everyday activity or competitive sport.

👉 Book your consultation today or call us on (02) 9389 9100 to start your recovery.