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Acromioclavicular (AC) Joint Injuries

Welcome to Orthosports Question for Physiotherapists October 2025. This month Dr Doron Sher discusses acromioclavicular joint injuries.

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QUESTION | HOW DO YOU DECIDE WHICH AC JOINT INJURIES NEED SURGERY?

ANSWER |

Acromioclavicular (AC) joint injuries are common in contact sports, often resulting from falls or direct trauma to the shoulder. While the deformity is seen at the AC joint the main injury is actually to the coracoclavicular ligaments. These resist superior movement while the AC joint capsule resists mainly AP displacement; and the Deltoid and Trapezius attachments provide dynamic stability.

The most common mechanism of injury is direct trauma with a fall onto the point of the shoulder (such as a rugby tackle). Indirect trauma such as falling onto an outstretched hand with transmission of force to the AC joint is far less common.

Classification

Cadenat was probably the first to document the injury in 1917 (The treatment of dislocations and fractures of the outer end of the clavicle. Int Clin 1917) and Allman and Tossy (CORR 1963 ) initially described 3 levels of joint separation. This was modified by Rockwood (1996) into 6 subtypes and this continues to be the most used classification nowadays.

Examination

Injury to the AC joint is often a relatively high energy injury and it is important to rule out injuries to the surrounding structures. This includes examination of the glenohumeral joint, sternoclavicular joint, cervical spine and ribs as well as a neurovascular examination. It is possible to injure the glenoid labrum, biceps and rotator cuff at the time of injury.

The clinical findings are usually very obvious with pain and swelling or a large lump at the AC joint. The patient will typically be unable to raise their arm above shoulder height or across their body. The tests described to diagnose this condition are: The cross-body adduction test, O’Brien’s test (AC variant), AC shear test and Paxinos test but the diagnosis is usually very obvious in anything greater than a grade I injury.

The ‘collapse sign’ is often used to decide whether to operate on type III injuries where an external rotation strength test is performed with the arm in adduction. It is considered positive if the clavicle rides up and over the acromion with the shoulder girdle moving medially or ‘collapsing’ under the clavicle, often indicating greater AP instability as well as superior/inferior instability.

Imaging

The diagnosis is made both clinically and from plain radiographs. It is important to obtain an axillary lateral to see if the clavicle has moved posteriorly as well as superiorly. The Zanca view is designed to look specifically at the AC joint and may need to be specifically requested (Most good imaging centres will do this automatically if you write AC joint injury in the clinical notes of the xray request form). Stress views are rarely done these days as surgery is almost never indicated if the joint is not separated with the arm at rest. MRI scanning can be used in cases where injury to other structures around the shoulder is suspected or to evaluate the coracoid for a fracture as this may affect treatment options.

Treatment

Non Operative Management

Types I–III is symptom based, not time based. The numbers below are a general guide only.

Phase 1: Acute (0–2 weeks)
Sling for comfort (Type I: ~3–5 days; Type II/III: ~10–14 days).
Ice, anti-inflammatories, pain management.
Early pendulum exercises, scapular setting, gentle AROM within pain limits. No specific restrictions on the use of the arm.

Phase 2: Subacute (2–6 weeks)
Progress to full AROM by week 4–6.
Sometimes a cortisone injection is required for pain relief
Initiate isometric rotator cuff strengthening, scapular stabilization, and closed-chain drills.
Avoid cross-body loading and overhead lifting initially if these cause pain

Phase 3: Advanced (6–10+ weeks)
Eccentric and plyometric training (e.g., wall dribbles, perturbation training).
Progressive strength and power work—bench press, push-ups. Avoid military press and lateral raises >60 degrees until completely symptom free.
Reintroduce sport-specific drills (passing, tackling technique, throwing).
A horse shoe shaped pad can be taped to the acromion to relieve direct pressure on the distal clavicle.

Return-to-Play (RTP) Considerations
Type I–II: RTP 2–4 weeks (non-contact sports), 4–6 weeks (contact).

Type III: RTP varies from 6–12 weeks depending on:
Symptom resolution, Strength symmetry, Sport-specific loading tolerance.

Criteria-based RTP should include:
No AC joint tenderness or instability,
Full pain-free ROM and strength,
Full contact simulation if applicable.

Operative Management Surgery is best performed within 3 weeks of the injury. Beyond 6 weeks they are generally treated the same as chronic injuries (see below) so early referral is essential.

The principles of the operation are to reduce the AC joint and reconstruct the coracoclavicular ligaments. There are many different operations that achieve the same outcome but each has different advantages and risks.

My approach is to perform one operation with a low risk profile that does not require a second operation to remove hardware before the person can return to sport. The described operations to treat this condition vary from a simple dacron graft reconstruction and AC joint repair to drill holes and metal buttons, use of tendon grafts and insertion of a hook plate which needs to be removed with another operation 6-12 weeks later. My technique is described in the handout in the link at the bottom of this page.

Treatment of chronic injuries usually requires the addition of fresh biology such as tendon grafts to achieve healing.

Rehab Principles
A sling is used for 6 weeks to protect the repair
Weeks 0-3       Pendular exercises only
Weeks 3-6       Passive ROM, stay in sling when not exercising
Week 6 onwards         Strength progression. Professional athletes usually resume contact at 8 weeks but for most patients this takes 12 weeks to be comfortable

Chronic AC Joint Pathology
The main indications for treatment are persistent pain with activities such as bench press, overhead lifting, or contact sports. Some patients do feel the AC joint instability. Some occupations like scaffolders and electricians who spend a lot of their work day with their hand overhead can feel scapula fatigue / pain as well. Non operative treatment is always tried first but a delayed reconstruction can still give excellent outcomes. It is often a combined procedure using a synthetic graft combined with a tendon (autograft or allograft for vertical stability) and another procedure to deal with AP stability such as a Weaver Dunne procedure, excision of the distal clavicle or other soft tissue reconstruction to stabilise the AC joint.

Conclusion
Grade I and II injuries are best treated non operatively.
Early referral for higher grades is needed.
Most Grade III injuries can be treated without surgery but there are certain cases where surgery is beneficial.
Grade IV-VI injuries do best with early surgery
Functional recovery from the surgery is generally very good

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Dr Doron Sher

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Sep-2020	Lumbar Stress Fractures	Dr Paul Annett
Aug-2020	Frailty and Healthy Ageing	Dr John Best
Jul-2020	Thumb – Collateral Ligament Tear	Dr Kwan Yeoh
Jun-2020	Shoulder Instability	Dr Doron Sher
May-2020	Hallux Rigidus	Dr John Negrine
Mar/Apr-2020	Achilles Tendon Ruptures	Dr Todd Gothelf
Feb-2020	Distal Biceps	Dr Doron Sher
Nov-2019	Clavicle Fracture Internal Fixation	Dr Doron Sher
Oct-2019	Femoracetabular Impingement (FAI)	Dr Paul Mason
Sep-2019	Imaging for Acute ACL Injuries	Dr Doron Sher
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Jul-2019	Guyon canal surgery	Dr Kwan Yeoh
Jun-2019	Whats new in ACL reconstruction 2019	Dr Doron Sher
May-2019	Cuneiform Fracture	Dr Todd Gothelf
Apr-2019	Flexor Tendon Injuries	Dr Kwan Yeoh
Mar-2019	Chronic Exertional Compartment Synd	Dr Paul Annett
Feb-2019	Achilles Tendon Rupture	Dr John Negrine
Nov-2018	Low Back Pain	Dr Paul Mason
Sep-2018	Concussion part 2	Dr John Best
Jul-2018	Concussion part1	Dr Paul Annett
Jun-2018	Thessaly & McMurray Test	Dr Doron Sher
May-2018	AC Joint	Dr Doron Sher
Apr-2018	Arthritis of the fingers	Dr Kwan Yeoh
Feb-2018	CLAVICLE fractures	Dr Doron Sher
Oct-2017	ACL Grafts	Dr Doron Sher
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Aug-2017	Wrist Ganglion	Dr Kwan Yeoh
Jul-2017	Anterolateral Ligament Reconstruction	Dr Doron Sher
Jun-2017	Scapholunate ligament	Dr Kwan Yeoh
Apr-2017	Knee Brace – ACL Reconstruction	Dr Doron Sher
Mar-2017	Sesamoid fractures	Dr Kwan Yeoh
Feb-2017	Plantar Fasciitis	Dr Todd Gothelf
Nov-2016	Sternoclavicular Joint	Dr Doron Sher
Oct-2016	Proximal Humerus Fractures	Dr David Lieu
Sep-2016	Wrist Fractures	Dr Kwan Yeoh
Aug-2016	Patella Instability	Dr Doron Sher
Jul-2016	Snowboarders ankle	Dr Todd Gothelf
May-2016	Cortisone Injections	Dr Paul Annett
Apr-2016	Shoulder Instability_1	Dr Ivan Popoff
Mar-2016	Exercise after TKR	Dr Doron Sher
Dec-2015	Scaphoid OA	Dr Kwan Yeoh
Nov-2015	Greater Tuberosity Fractures	Dr Doron Sher
Oct-2015	Stress Fractures	Dr Paul Annett
Sep-2015	Boxers Fractures	Dr Kwan Yeoh
Aug 2015	Resistance Training	Dr John Best
July 2015	LARS Ligament	Dr Ivan Popoff
Jun-2015	Distal Biceps	Dr Doron Sher
May-2015	Latarjet procedure	Dr Jerome Goldberg
Apr-2015	TFCC Questions	Dr Kwan Yeoh
Mar-2015	Acute Ankle Sprains	Dr Todd Gothelf
Nov-2014	PRPP	Dr Paul Annett
Oct-2014	Driving After Surgery	Dr Doron Sher
Sep-2014	Distal Biceps Rupture	Dr Doron Sher
Aug-2014	Ankle Sprain	Dr Todd Gothelf
Jun-2014	Patella Dislocation	Dr Doron Sher
May-2014	Shoulder Instability	Dr Todd Gothelf
Apr-2014	De Quervains	Dr Kwan Yeoh
Mar-2014	Acromio-clavicular joint injuries	Dr Todd Gothelf
Feb-2014	Chronic Knee Pain	Dr Paul Annett
Dec-2013	Foot and Ankle Questions	Dr John Negrine
Oct-2013	Rotator Cuff Repair	Dr Todd Gothelf
Sep-2013	ACL Reconstruction	Dr Doron Sher
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May-2013	Skiers thumb	Dr Kwan Yeoh
Apr-2013	Bakers_Cyst	Dr Ivan Popoff
Mar-2013	Tibial Osteotomy vs UKR	Dr Doron Sher
Feb-2013	ALIF success rate	Dr Andreas Loefler
Jan-2013	Lisfranc Injuries	Dr Todd Gothelf
Nov-2012	Anterior Spinal Fusions	Dr Andreas Loefler
Oct-2012	MCL Injuries	Dr Doron Sher
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July-2012	Anterior Process Calcaneus Fx	Dr Todd Gothelf
Jun-2012	Tenodesis vs Tenotomy	DrJeromeGoldberg
May-2012	Osteoarthritis in the young active patient	Dr Doron Sher
Apr-2012	Syndesmosis Sprain	Dr Todd Gothelf
Mar-2012	Triangular Fiocartilage Injuries	Dr Kwan Yeoh
Jan-2012	Shoulder Replacement Older Population	Dr Jerome Goldberg
Dec-2011	Wrist Fracture	Dr Kwan Yeoh
Nov-2011	Adductor Tendon Tear	Dr Paul Annett
Oct-2011	Navicular Pain	Dr Todd Gothelf
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Aug-2011	Metal on Metal Hip Replacements	Dr Andreas Loefler
July-2011	Femoral Neck Stress Fract (Pt 2)	Dr John Best
Jun-2011	Femoral Neck Stress Fractures	Dr John Best
May-2011	PCL Injury Part 2	Dr Doron Sher
Apr-2011	PCL Injury Part 1	Dr DoronSher
Mar-2011	Prolotherapy Autologous Blood Injections	DrPaul Annett
Feb-2011	Shoulder Impingement	Dr Todd Gothelf
Dec-2010	Does Chondral Grafting Work	DrDoron Sher
Nov-2010	Shoulder Immobilisation-Dislocation	Dr Jerome Goldberg
Sep-2010	SLAP Lesions Stable Shoulder	Dr ToddGothelf
Jul-2010	Ankle Sprains	Dr Todd Gothelf
Jun-2010	Dislocation After THR	Dr Peter Walker
May-2010	Acupuncture Muscle Strength Programmes	Dr Paul Annett
April-2010	Full Thickness Rotator Cuff Tears	Dr JeromeGoldberg
Mar-2010	Skiing after TKR	Prof Warwick Bruce
Feb-2010	Fractures of the Clavicle	Dr John Trantalis
Jan-2010	Osteoarthritis of the Knee	Dr Doron Sher
Dec-2009	Fifrth Metatarsal Fractures	Dr Todd Gothelf
Nov-2009	Partial Rotator Cuff Tears	Dr Todd Gothelf

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Question for Physiotherapists

Acromioclavicular (AC) Joint Injuries

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