14.2: Acromioclavicular Joint Separation
- Page ID
- 14881
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)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
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 |
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.