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14.2: Acromioclavicular Joint Separation

  • Page ID
    14881
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    Acromioclavicular (AC) Joint Separation/Dislocation

    Case

    Acromioclavicular joint dislocation

    Clinical:

    History – 21 year old female injured her shoulder while wrestling.

    Symptoms – This patient complained of a deformed, painful, end of her right collar bone.

    Physical – There was swelling and tenderness of the region of the acromioclavicular joint.

    DDx:

    Acromioclavicular Joint Separation

    Clavicle Fracture

    Acromion Fracture

    Hematoma

    Imaging Recommendation

    ACR – MSK – Acute Shoulder Pain, Variant 1

    Shoulder X-ray

    ODIN Link to AC Joint Separation images, Figure 14.2A and B: mistr.usask.ca/odin/?caseID=20150209202015857

    msk-2-2-1.jpg
    Figure 14.2A X-ray of the right shoulder, Y-view, with AC joint separation
    msk-2-3.jpg
    Figure 14.2B X-ray of the right shoulder, AP, with AC joint separation

    Imaging Assessment

    Findings:

    The lateral clavicle was displaced cranially and the acromioclavicular joint was widened. The coracoclavicular distance was also widened.

    Interpretation:

    Acromioclavicular joint dislocation, Type 3.

    Diagnosis:

    Acromioclavicular joint dislocation

    Discussion:

    Acromioclavicular joint injuries can be graded on the 6-point Rockwood scale:

    Type AC Joint CC Joint Reducibility Treatment
    I Sprain Normal NA Conservative
    II Torn Sprain – CC distance <25% of the contralateral side Reducible Conservative
    III Torn Torn – CC distance increased 25 – 100 % of the contralateral side Reducible or Non-Reducible Conservative or Surgical
    IV Torn Torn – Posterior displacement of clavicle into the trapezius muscle Not Reducible Surgery
    V Torn Torn – CC distance > 100% of the contralateral side with the clavicle protruding through the delto-trapezial fascia Not Reducible Surgery
    VI Torn Torn – Clavicle caudal to the subacromial or subcoracoid Not Reducible Surgery
    msk-2-4-1024x768.jpg
    Figure 14.3 Acromioclavicular injury classification

    X-ray findings may include:

    • Minor injuries of this joint space usually involve only the joint capsule and the acromioclavicular ligament.
    • With more severe injuries the coracoclavicular ligament may be torn leading to a more displaced clavicle and a wider coracoclavicular distance.
    • Severe injuries can involve the coracoclavicular ligament, the deltoid muscle and the trapezius muscle.

    Attributions

    Figure 14.2A X-ray of the right shoulder with AC joint separation by Dr. Brent Burbridge MD, FRCPC, University Medical Imaging Consultants, College of Medicine, University of Saskatchewan is used under a CC-BY-NC-SA 4.0 license.

    Figure 14.2B X-ray of the right shoulder with AC joint separation by Dr. Brent Burbridge MD, FRCPC, University Medical Imaging Consultants, College of Medicine, University of Saskatchewan is used under a CC-BY-NC-SA 4.0 license.

    Figure 14.3 Acromioclavicular injury classification. Courtesy of Dr. Roberto Schubert, Radiopaedia.org, RID: 19124. Originally published at https://radiopaedia.org/cases/rockwood-classification-system-of-acromioclavicular-joint-injuries under a Creative Commons Attribution-Non-commercial-Share Alike 3.0 License.


    This page titled 14.2: Acromioclavicular Joint Separation is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Brent Burbridge and Evan Mah via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.