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Acromioclavicular Joint Arthritis

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Other Names

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

Radiograph demonstrating AC joint OA


  • This page refers to atraumatic, chronic and arthritic pain of the Acromioclavicular Joint (AC Joint)
    • This commonly represents degenerative changes and osteoarthritis
    • There may also be atraumatic AC joint pain without evidence of arthritis


  • Most common cause of AC joint pain (need citation)


Primary Osteoarthritis

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

Secondary Osteoarthritis

  • Post-traumatic
    • Most commonly occuring with an axial load on an abducted arm[1]
  • Distal clavicle osteolysis
    • Related to repetitive microtrauma[2]
    • Most commonly in weight lifters, less commonly basketball, swimming
  • Inflammatory arthropathies including Rheumatoid Arthritis, Gout, and Pseudogout
  • Septic arthritis
    • Uncommon in AC joint but risk factors include trauma, recent surgery, IV drug abuse, immune compromised, and hematogenous seeding among many others[3]
  • Joint instability
    • Due to local elevation of contact stresses, dynamic loss of joint congruity, and alterations in range of motion[4]


Associated Injuries

Risk Factors

  • Sports
    • Weightlifting
    • Basketball
    • Swimming

Differential Diagnosis

Clinical Features

  • History
    • Can be difficult to distinguish from other causes of shoulder pain
    • Often other pathology co-occurs including rotator cuff tears, labral injuries and biceps tendonitis
    • Patient may report pain with passive and active range of motion
    • Pain typically anterior shoulder but can but can be referred to 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 flexs, adducts arm across body
    • Resisted AC Joint Extension Test: Flex, internally rotatoe shoulder and abduct against resistance
    • OBriens Test: Shoulder flexed to 90, flexes further against resistance
      • Crossover test most sensitive (77%), O'Briens Test is most specific (95%)[9]
    • One Finger Test: Have patient point to 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° cephalid 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


  • N/A




  • Indications
    • Failure of non-operative therapy
  • Technique
    • Arthroscopic clavicle resection
    • Open clavicle resection (Mumford procedure)

Rehab and Return to Play


  • Dictated in part by concomitant procedures[15]
  • Distal clavicle excision
    • Immobilized in shoulder sling, allowed to perform pendulums
    • 2 weeks: begin passive, active range of motion
    • 4 weeks: discontinue immobilization, full range of motion permitted
  • Note: If significant deltoid dissection, flexion and abduction restricted up to 6 weeks

Return to Play

  • Needs to be updated


  • Surgical
    • AC Joint instability due to excessive clavicle resection
    • Persistent pain due to incomplete resection
    • Heterotopic Ossification
    • Deltoid dehiscence

See Also


  1. Mazzocca, AD, Arciero, RA, Bicos, J. Evaluation and treatment of acromioclavicular joint injuries. Am J Sports Med. 2007;35(2):316-329.
  2. Charron, KM, Schepsis, AA, Voloshin, I. Arthroscopic distal clavicle resection in athletes: a prospective comparison of the direct and indirect approach. Am J Sports Med. 2007;35(1):53-58.
  3. Bossert, M, Prati, C, Bertolini, E, Toussirot, E, Wendling, D. Septic arthritis of the acromioclavicular joint. Joint Bone Spine. 2010;77(5):466-469.
  4. Shu, B, Johnston, T, Lindsey, DP, McAdams, TR. Biomechanical evaluation of a novel reverse coracoacromial ligament reconstruction for acromioclavicular joint separation. Am J Sports Med. 2012;40(2):440-446.
  5. Brown, JN, Roberts, SN, Hayes, MG, Sales, AD. Shoulder pathology associated with symptomatic acromioclavicular joint degeneration. J Shoulder Elbow Surg. 2000;9(3):173-176.
  6. Mazzocca, AD, Arciero, RA, Bicos, J. Evaluation and treatment of acromioclavicular joint injuries. Am J Sports Med. 2007;35(2):316-329.
  7. Chronopoulos, E, Kim, TK, Park, HB, Ashenbrenner, D, McFarland, EG. Diagnostic value of physical tests for isolated chronic acromioclavicular lesions. Am J Sports Med. 2004;32(3):655-661.
  8. Hegedus, EJ, Goode, A, Campbell, S. Physical examination tests of the shoulder: a systematic review with meta-analysis of individual tests. Br J Sports Med. 2008;42(2):80-92; discussion 92.
  9. Chronopoulos, E, Kim, TK, Park, HB, Ashenbrenner, D, McFarland, EG. Diagnostic value of physical tests for isolated chronic acromioclavicular lesions. Am J Sports Med. 2004;32(3):655-661.
  10. Ernberg, LA, Potter, HG. Radiographic evaluation of the acromioclavicular and sternoclavicular joints. Clin Sports Med. 2003;22(2):255-275.
  11. Alasaarela, E., et al. "Ultrasound evaluation of the acromioclavicular joint." The Journal of rheumatology 24.10 (1997): 1959-1963.
  12. Borbas, Paul, et al. "The influence of ultrasound guidance in the rate of success of acromioclavicular joint injection: an experimental study on human cadavers." Journal of shoulder and elbow surgery 21.12 (2012): 1694-1697.
  13. Sabeti-Aschraf, Manuel, et al. "Ultrasound guidance improves the accuracy of the acromioclavicular joint infiltration: a prospective randomized study." Knee Surgery, Sports Traumatology, Arthroscopy 19.2 (2011): 292-295.
  14. Docimo, S, Kornitsky, D, Futterman, B, Elkowitz, DE. Surgical treatment for acromioclavicular joint osteoarthritis: patient selection, surgical options, complications, and outcome. Curr Rev Musculoskelet Med. 2008;1(2):154-160.
  15. Mall, Nathan A., et al. "Degenerative joint disease of the acromioclavicular joint: a review." The American journal of sports medicine 41.11 (2013): 2684-2692.
Created by:
John Kiel on 4 July 2019 08:28:23
Last edited:
1 October 2022 19:07:06