Diagnosis of a symptomatic AC Joint | Two AC Joint Test Clusters

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Diagnosis of a symptomatic AC Joint | Two AC Joint Test Clusters

When evaluating a patient with shoulder pain, the AC joint may be a source of potential nociception. In the past, we have published a diagnostic test cluster for the AC joint by Chronopoulos et al. from the year 2004 which claims high diagnostic accuracy.The problem with this study is that it contains several methodological shortcomings which could have led to biased results. A new systematic review by Krill et al. in the year 2018 has evaluated different special tests for the AC joint and have found the following:

A combination of a positive Paxino’s Sign followed by a positive Active Compression Test of O’Brien yielded a specificity of 95,8% and a positive likelihood ratio of 2.71 to confirm a symptomatic AC joint
A combination of a negative Paxino’s Sign and a negative Hawkins-Kennedy Test yielded a sensitivity of 93,7% with a negative likelihood ratio of 0.35

Although the systematic review used strict criteria, the diagnostic accuracy of these two clusters is rather low. At the same time, it is currently the best physical tool we have to diagnose a symptomatic AC joint, which is we give those two clusters a moderate clinical value.

To perform the Paxinos sign the patient is in sitting position with a relaxed arm. Stand behind the patient’s symptomatic side. Then put your thumb onto the posterolateral aspect of the acromion and your index and long finger of the same or the contralateral hand are placed superior to the midpart of the ipsilateral clavicle. style=”font-Then apply pressure to the acromion with your thumb in an anterosuperior direction and inferiorly to the midpart of the clavicular shaft with the index and long fingers.This test is positive if fain is felt or increases in the region of the AC joint.

In case of a positive test, you should continue with the Active Compression Test. To perform the Active Compression Test have your patient standing with his shoulders flexed to 90° and in full internal rotation so that his thumbs are facing down. The elbows have to be straight and the shoulders are adducted horizontally 10 to 15 degrees. It’s easy to standardize this position just by having the patient make contact with the dorsum of both hands. Then the examiner applies downward pressure that is resisted by the patient.Then the same test is repeated with the patient’s palms facing upwards.

This test is positive if the first testing position causes pain in the area of the AC joint and the pain is less or absent in the second maneuver.

In case of a negative Paxino’s Sign, you should carry out the Hawkins-Kennedy Test.

To perform this test according to its original description and how it was conducted in the study, have your patient in sitting position with the affected arm in 90 degrees of forward flexion and the elbow flexed to 90 degrees, and the scapula fixated with one hand. Then the examiner holds onto the patient’s elbow with his other hand and performs an internal rotation of the glenohumeral joint.

This test is positive if the pain is reported upon internal rotation and may be as small as a “facial expression”

In case both tests are negative, the chances for the AC joint as the source of nociception are moderately decreased.