AC Joint Cluster by Chronopoulos | AC Joint Diagnosis

When evaluating a patient with shoulder pain, especially male manual workers or those who train in the gym the acromioclavicular or AC joint may be the source of pain.

Chronopoulos et al. (2004) suggest a test item cluster of three provocative tests. These are the Cross Body Adduction test, the AC resisted extension or shear test, and the Active Compression Test also known as O’Brien’s test.

In case of a positive test for all three items, the sensitivity is at 25% and specificity is reported at 97%.

To conduct the cross-body adduction test, the patient may be sitting. Elevate the arm to 90° of flexion and then add maximum horizontal adduction.
A positive test will reproduce pain on top of the shoulder near the AC joint.

The AC resisted extension test or shear test is performed as follows. With the patient in sitting position elevate the arm to 90° of flexion. Now the patient is asked to resist horizontal adduction by pushing against the examiner’s hand.
Again, a positive test will reproduce pain on top of the shoulder near the AC joint.

Lastly, assess the O’Brien or active compression test.  The patient’s arm is elevated to 90° of flexion with 10° of horizontal adduction. The arm is placed in full IR so that the thumb faces downwards and the patient should resist downward force applied by the examiner. Consequently, the test is repeated with the arm in external rotation.
A positive test will show in the reproduction of symptoms in the first testing position which disappears in the second testing position.

21 OF THE MOST USEFUL ORTHOPAEDIC TESTS IN CLINICAL PRACTICE

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Other common orthopedic tests to assess for AC Joint Pathology are:

• Cross Body Adduction Test
• Active Compression Test of O’Brien
• AC Joint Line Tenderness
• Paxinos Sign
• AC Resisted Extension Test
• AC Shear Test
• AC Joint Provocation Cluster by Krill
• AC Joint Provocation Cluster by Chronopoulos

Chronopoulos, E., Kim, T. K., Park, H. B., Ashenbrenner, D., & McFarland, E. G. (2004). Diagnostic value of physical tests for isolated chronic acromioclavicular lesions. The American journal of sports medicine, 32(3), 655-661.