What is Drop Arm Test (Sign)?
The drop arm test is used for diagnosing rotator cuff tendon tear, especially the supraspinatus tendon tear. This test helps in determining if there is a tear in the supraspinatus tendon. The rotator cuff is a common name for a group of 4 muscles and their tendons. The rotator cuff includes these four following muscles supraspinatus, infraspinatus, teres minor, subscapularis.
The drop arm test is also known as Codman’s test or Codman’s sign. This test also helps in differentiating between the shoulder and rotator cuff pathologies.
Procedure for Performing Drop Arm Test
There are many procedures for performing the drop arm test.
- Ask the patient to lift their arm as high as possible or fully abduct the arm. Then, ask the patient to slowly lower the arm to 90 degrees.
- Now, if there is a tear in the rotator cuff tendon, especially the supraspinatus tendon, the patient will not be able to hold their arm at 90 degrees of abduction, and it will drop to her side and also the patient can’t lower their arm smoothly and slowly, even after many attempts.
Note – If the supraspinatus tendon tear patient can hold their arm at 90 degrees of abduction, slight pressure on the forearm can cause the arm to drop to the side.
- The examiner passively brings the patient’s affected shoulder into 90 degrees of abduction and full external rotation. After that, the examiner supports the arm at the elbow.
- The examiner removes his hand (support) from the patient’s arm and gives instructions to the patient to slowly lower the arm back to the neutral.
Positive Drop Arm Test
The drop arm test is considered positive when the patient cannot hold their arms at 90° of abduction or can not control the lowering of the arm to their side. The patient may also feel pain and weakness while lowering the arm. All these things indicate a massive supraspinatus tendon tear.
Negative Drop Arm Test
The test is considered negative when the patient can control the lowering of the arm slowly and smoothly without any pain or weakness.
Sensitivity / Specificity
The sensitivity of detecting a supraspinatus tendon tear is 73%, while the specificity is 77%.
The accuracy of the drop arm test is likely to be more significant when it’s used in conjunction with other tests, such as:
- Empty/full can test
- Internal Rotation Lag Sign
- External Rotation Lag Sign
A series of tests can help you to distinguish between the rotator cuff muscles. This will allow you to make a more precise diagnosis, and it also lessens the costs of radiographic imaging like US or MRI.
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