Empty Can Test

Original Editor - Tyler Shultz

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Purpose

The Empty Can Test, also known as the Jobe or Supraspinatus test, is used to assess for lesions of the rotator cuff, specifically the supraspinatus muscle and supraspinatus tendon.

Technique

1. The patients arm is actively abducted to 90^o
2. The examiner applies downward resistance to the abducted arm
3. With the patient's hand in a fist, and the thumb sticking out, the shoulder is actively internally rotated, and angled forward to 30^o, so that their thumb is in a downward facing direction (empty can position), in the scapular plane

Instructional Video

Here is a video demonstrating the Empty Can Test:

Interpretation

Testing the arm with the thumb in 'thumbs up' (full can position) is most suitable for maximal contraction of the supraspinatus muscle.

Resistance is provided by the examiner, as they are assessing for weakness or pain. Weakness or pain would represent a positive test, which would indicate a tear of the supraspinatus muscle or tendon, or a neuropathy of the suprascapular nerve.

This can also indicate supraspinatus paratenonitis.

Evidence

Boettcher CE, et al. demonstrated with normalized EMG that the Empty Can Test activates supraspinatus to levels approximately 90% MVC. Concurrent activation of other shoulder muscles tested including other rotator cuff muscles (infraspinatus and upper subscapularis), scapular positioning muscles (upper, middle and lower trapezius, and serratus anterior), and abduction torque producing muscles (anterior, middle & posterior deltoid) were activated to similarly high levels.

Therefore, the Empty Can Test must be questioned as a valid diagnostic tool for isolated supraspinatus pathology, due to the high activation of many shoulder muscles simultaneously.

The Empty Can Test has a specificity of 55% for Pain, 68% for muscle weakness, as well as 50% for pain, muscle weakness, or both.

The Empty Can Test has a sensitivity of 63% for Pain, 77% for muscle weakness, as well as 89% for pain, muscle weakness, or both.

There is a positive likelihood ratio of 1.40 for pain, 2.41 for muscle weakness, and 1.78 for pain, muscle weakness, or both.

There is a negative likelihood ratio of 0.67 for pain, 0.34 for muscle weakness, and 0.22 for pain, muscle weakness, or both.