Acromioclavicular Joint Arthritis

Last updated: February 8, 2026Reviewed date: February 8, 2026Reading time: 4 min read
Patient Tools

Read, save, and share this guide

Use these quick tools to make this medical article easier to read, print, save, or share with a family member.

On this page10 sections

Article Summary

Acromioclavicular joint osteoarthritis is a type of shoulder arthritis that involves degenerative changes to the cartilage and other structures in the acromioclavicular joint. AC joint arthrosis or osteoarthritis of the acromioclavicular joint is most common in people who are middle-aged. It develops when the cartilage in the AC joint begins to wear out. With this condition, there is usually pain that limits the motion of...

Key Takeaways

  • This article explains Other Names in simple medical language.
  • This article explains Pathophysiology in simple medical language.
  • This article explains Differential Diagnosis in simple medical language.
  • This article explains Diagnosis in simple medical language.
Before reading

RX Patient Tools

Use these quick guides before reading the article, or return to them when you need help preparing questions for a doctor.

Start here Choose the right pathway for symptoms, reports, medicines, or urgent warning signs. Disease article roadmap Read this topic step by step: meaning, symptoms, warning signs, diagnosis, treatment, prevention, and follow-up. Treatment planner Prepare questions about treatment choices, benefits, risks, side effects, and follow-up. Family & caregiver guide Organize symptoms, reports, medicines, questions, and follow-up safely. Nutrition & diet guide Prepare food, hydration, supplement, and medicine-timing questions safely. Prevention guide Organize risk factors, protective habits, screening, and warning signs. Recovery guide Prepare a safe plan for activity, rehabilitation, warning signs, and follow-up.
Educational health guideWritten for patient understanding and clinical awareness.
Reviewed content workflowUse writer and reviewer profiles for stronger trust.
Emergency safety firstUrgent warning signs are highlighted below.
Choose your reading view

Patient View highlights a simple learning journey. Clinical View reveals structure, evidence, and editorial completeness.

Definition

Acromioclavicular joint is a type of shoulder that involves degenerative changes to the and other structures in the acromioclavicular joint. AC joint arthrosis or osteoarthritis of the acromioclavicular joint is most common in people who are middle-aged. It develops when the cartilage in the AC joint begins to wear out. With this condition, there is usually that limits the motion of the arm. Initial treatment of AC joint arthritis is non-operative and includes activity modification, , non-steroidal medications (NSAIDs), and local AC joint injection of anesthetics or corticosteroids

Other Names

  • AC Joint
  • Acromioclavicular Joint Osteoarthritis
  • Degenerative Joint Disease of the Acromioclavicular Joint

Pathophysiology

Primary Osteoarthritis

  • Refers to age-related degeneration
  • Intra-articular disc
    • Functions like the of the knee
    • Prone to fraying, tearing, and forming holes, macerated by defects in the chondral surface

Secondary Osteoarthritis

  • Post-traumatic
    • Most commonly occurring with an axial load on an abducted arm
  • Distal osteolysis
    • Related to repetitive microtrauma
    • Most commonly in weight lifters, less commonly basketball, swimming
  • Inflammatory arthropathies including , , and Pseudogout
    • Uncommon in AC joint but risk factors include , recent surgery, IV drug abuse, immune-compromised, and hematogenous seeding among many others
  • Joint instability
    • Due to local elevation of contact stresses, dynamic loss of joint congruity, and alterations in range of motion
  • Static Stabilizers
    • Acromioclavicular
    • Coracoclavicular
  • Dynamic Stabilizers
    • Deltoid
    • Trapezius
    • Serratus Anterior

Associated Injuries

  • Includes, but not limited to[5]
    • Rotator Cuff
    • Glenoid Labral Tears
    • Proximal Biceps Injuries
  • Sports
    • Weightlifting
    • Basketball
    • Swimming

  • Fractures
    • Proximal
    • Humeral Shaft Fracture
    • Clavicle Fracture
    • Fracture
    • First Rib Fracture (traumatic or atraumatic)
  • Dislocations & Seperations
    • Acromioclavicular Joint Separation
    • Glenohumeral  ()
    • Sternoclavicular
    • Glenohumeral Instability ()
  • Arthropathies
    • Glenohumeral Arthritis
    • Acromioclavicular Joint Arthritis
  • Muscle & Tendon Injuries
    • Pectoralis Major Injuries
    • Pectoralis Minor Injuries
    • Proximal Biceps Tendon Injuries
    • Scapular Dyskinesis
  • Rotator Cuff
    • Rotator Cuff Tear
    • Rotator Cuff Tendonitis
    • Calcific of the Rotator Cuff
    • Subcoracoid Impingement
  • Bursopathies
    • Subacromial Bursitis
    • Scapulothoracic Bursitis
  • Ligament Injuries
    • Glenoid Labral Tears
  • Neuropathies
    • Suprascapular Nerve Injury
    • Parsonage-Turner Syndrome
    • Quadrilateral Space Syndrome
    • Winged Scapula
  • Other
    • Adhesive Capsulitis
    • Paget-Schroetter Syndrome
  • Pediatrics
    • Coracoid Avulsion Fracture
    • Humeral Head Epiphysiolysis (Little League Shoulder)

Diagnosis

  • History
    • Can be difficult to distinguish from other causes of shoulder pain
    • Often another pathology co-occurs including rotator cuff tears, labral injuries, and biceps tendonitis
    • The patient may report pain with passive and active range of motion
    • Pain typically anterior shoulder but can be referred to as anterolateral neck, anterolateral deltoid, and trapezius[6]
  • Physical: Physical Exam Shoulder
    • Inspection: AC Joint may demonstrate swelling, deformity, or prominence[7]
    • Tenderness to AC joint is sensitive, not specific[8]
  • Special Tests
    • Crossover Test: Examiner passively flexes, adducts arm across body
    • Resisted AC Joint Extension Test: Flex, internally rotate the shoulder and abduct against resistance
    • OBriens Test: Shoulder flexed to 90, flexes further against resistance
      • The crossover test most sensitive (77%), O’Briens Test is the most specific (95%)[9]
    • One Finger Test: Have the patient point to the most painful spot with 1 finger (AC joint = positive)
Ultrasound demonstrating AC joint OA
  • Radiographs
    • Typically begin with Standard Radiographs Shoulder
    • Zanca View: 10-15° cephalad tilt best visualizes joint
    • OA Findings: joint space narrowing, subchondral cysts, osteophytes, and subchondral sclerosis
    • May see distal clavicle osteolysis
    • Asymptomatic AC joint OA findings are common (need citation)
  • CT
    • Allows superior osseous visualization[10]
  • MRI
    • Superior visualization of soft tissue lesions
  • Ultrasound
    • Ultrasound can detect AC joint changes reliably[11]
    • Sensitivity and specificity for arthritis are unknown
  • Diagnostic Injection
    • See: Acromioclavicular Joint Injection
    • The diagnostic injection can help clarify the etiology of shoulder pain
    • Ultrasound improves injection accuracy from 70%-75% to 90%-98%[12][13]

Treatment

Nonoperative

  • First-line therapy in most patients
  • Activity Modification
    • Avoid: aggravating activities such as cross-body, pushing, weight lifting, throwing, overhead work
  • Physical Therapy
    • Can help with range of motion, flexibility, and strength[14]
  • Temporary immobilization with Shoulder Sling in the setting of acute exacerbation
  • Medications including NSAIDs, Acetaminophen
  • Corticosteroid Injection
    • See: Acromioclavicular Joint Injection

Operative

  • Indications
    • Failure of non-operative therapy
  • Technique
    • Arthroscopic clavicle resection
    • Open clavicle resection (Mumford procedure)
More from this topic
  1. Radio-Ulnar Terminal Transverse Meromelia

    DefinitionRadio-ulnar terminal transverse meromelia is a birth problem where the baby is born without the forearm bones (radius? and ulna?) and without the hand on that...

    March 4, 2026 • Rx Musculoskeletal Conditions
  2. Congenital Absence of Both Forearm and Hand

    DefinitionCongenital? absence of both forearm and hand is a rare birth condition. In this condition, the baby is born with the upper arm present, but the...

    March 4, 2026 • Rx Musculoskeletal Conditions
  3. Cone Dystrophy

    DefinitionCone dystrophy is a rare eye disease where the cone cells in the retina? slowly stop working properly. Cone cells are the light-sensing cells that help...

    March 2, 2026 • Rx Musculoskeletal Conditions
  4. Collagen VI-Related Muscular Dystrophy

    DefinitionCollagen VI-related muscular dystrophy is a group of rare genetic? muscle diseases where the body makes collagen type VI in an abnormal way. Collagen VI is...

    February 10, 2026 • Rx Musculoskeletal Conditions
  5. Collagen VI-Related Muscle Disorder

    DefinitionCollagen VI-related muscle disorder is a group of rare genetic? diseases that weaken the muscles of the body and also affect the soft connective tissue around...

    February 10, 2026 • Rx Musculoskeletal Conditions
  6. Collagen VI-Related Dystrophy

    DefinitionCollagen VI-related dystrophy is a group of rare genetic? diseases that damage the muscles and the supporting tissues around them. In this condition, the body has...

    February 10, 2026 • Rx Musculoskeletal Conditions
  7. Collagen 6-Related Myopathy

    DefinitionCollagen 6-related myopathy? (often written as collagen VI-related myopathy) is a rare inherited? muscle disease. It happens when there is a change (mutation) in the genes...

    February 10, 2026 • Rx Musculoskeletal Conditions
  8. Classic Multiminicore Myopathy

    DefinitionClassic multiminicore myopathy? is a rare inherited? muscle disease that starts very early in life and stays for the whole lifetime. It belongs to a group...

    January 28, 2026 • Rx Musculoskeletal Conditions
  9. Myoseptumitis

    DefinitionMyoseptumitis is a medical word that means inflammation? of the myoseptum, which is the thin wall of tissue inside a muscle that separates small bundles of...

    January 8, 2026 • Rx Musculoskeletal Conditions
  10. Myoseptum Inflammation

    DefinitionMyoseptum inflammation? is a thin sheet of strong connective tissue that lies between blocks of muscle fibers. It acts like a wall or partition inside the...

    January 8, 2026 • Rx Musculoskeletal Conditions
RX Clinical Pathway Engine

Continue through a complete learning pathway

Move from understanding the topic to symptoms, tests, treatment, medicines, monitoring, and prevention.

Search the complete library
  1. Understand the condition Begin with the essential facts and a clear explanation of the topic.
  2. Recognize symptoms Learn common symptoms, signs, and patterns of presentation.
  3. Know when to seek help Review urgent warning signs and when professional assessment may be needed.
  4. Understand causes and risks Explore causes, risk factors, mechanisms, and contributing conditions.
  5. Explore tests and diagnosis Learn how clinicians assess the condition and which investigations may be discussed.
  6. Learn treatment approaches Review general treatment categories and management principles.
  7. Understand medicines safely Continue to medicine education, uses, precautions, and monitoring.
  8. Plan monitoring and follow-up Understand monitoring, complications, rehabilitation, and follow-up learning.
  9. Review prevention and self-care Explore prevention, healthy routines, and questions to discuss with a clinician.

Conditions & Diseases

Background, symptoms, causes, diagnosis, and care.

Explore this library

Tests & Investigations

Laboratory, imaging, screening, and diagnostic education.

Explore this library

Medicines

Uses, safety, monitoring, and related medicine knowledge.

Explore this library

Cancer Knowledge

Cancer types, screening, oncology, and treatment education.

Explore this library
Doctor visit helper

Prepare before seeing a doctor

A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Orthopedic doctor, rheumatologist, or physiotherapist depending on cause.

What to tell the doctor

  • Write which joints hurt, swelling, morning stiffness duration, fever, injury, and walking difficulty.
  • Bring X-ray, uric acid, ESR/CRP, rheumatoid factor, or previous reports if available.

Questions to ask

  • Is this injury, osteoarthritis, rheumatoid arthritis, gout, infection, or another cause?
  • Which exercises, supports, or lifestyle changes are safe?
  • Do I need blood tests or X-ray?

Tests to discuss

  • Joint examination and range of motion
  • X-ray when chronic arthritis or injury is suspected
  • ESR/CRP, uric acid, rheumatoid tests when inflammatory arthritis is suspected

Avoid these mistakes

  • Do not ignore hot swollen joint with fever.
  • Avoid repeated steroid injections/tablets without a clear diagnosis and follow-up.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

Safe first steps

  • Avoid heavy lifting, sudden bending, and prolonged bed rest.
  • Use comfortable posture and gentle movement as tolerated.
  • Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

  • For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
  • Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

  • Do not start antibiotics without a proper medical decision.
  • Do not use steroid tablets or injections casually for quick relief.
  • Do not delay emergency care because of home remedies.

Get urgent help if

  • Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.
Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

For rural patients and family caregivers

Patient health record and symptom diary

Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

Doctor to discuss: Doctor / qualified healthcare provider
Tests to discuss with doctor
  • Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
  • Relevant blood, urine, imaging, or specialist tests only after clinical assessment
Questions to ask
  • What is the most likely cause of my symptoms?
  • Which warning signs mean I should go to emergency care?
  • Which tests are really needed now?
  • Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Safe pathway to proper treatment

Care roadmap for: Acromioclavicular Joint Arthritis

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. Step 5

    Follow up and return early if worse

    If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips
  • Take a written symptom diary and all previous prescriptions/test reports.
  • Do not hide medicines already taken, even herbal or over-the-counter medicines.
  • Ask which warning signs mean urgent referral to hospital.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.