Subacromial Injection Test

Subacromial injection test is an injection procedure used to test for subacromial Impingement Syndrome of the rotator cuff of the shoulder.

How do you perform the Subacromial Injection procedure?

• Under sterile conditions, the region beneath the anterior acromion (subacromial space) is infiltrated, preferable intrabursally, with a local anesthetic of 10 ml of 1% lidocaine and a corticosteroid when indicated.
• To open the subacromial space, the patient is asked to let the arm relax and hang down loosely. The weight of the arm opens the subacromial space, but only if the patient is sufficiently relaxed.
• After the injection, the active range of movement and the painful provocation tests are retested and evaluated.

See Also: Neer Test

What does a positive Subacromial Injection test mean?

Subacromial injection test is positive if the pain that is caused by impingement usually is significantly reduced or eliminated.

The pain caused by other conditions (with the exception perhaps of calcific tendinitis) is not relieved.

Notes

• After a subacromial injection, it is necessary to observe the patient for some time to allow one to recognize and treat medication-related cardiovascular reactions in a timely fashion.
• The patient must be warned that the shoulder can be temporarily quite painful, and movement may be limited by pain after an injection.
• In addition, inflammatory, nonbacterial changes in the shoulder can develop after an injection, especially with a steroid injection .

Subacromial Injection

Posterior Approach

• Patient is placed in the seated position with their affected upper extremity resting comfortably at their side on the chair’s arm rest with the shoulder in an internally rotated position.
• Examine the posterolateral aspect of the shoulder looking for evidence of overlying cellulitis (avoid placing the needle through any area of potential infection).
• Palpate the posterior and lateral borders of the acromion process localizing its most posterolateral aspect and palpate the coracoid process anteriorly.
• Localize the posterolateral soft spot between the humeral head and the glenoid approximately two finger breadths distal and one finger breadth medial to the posterolateral corner of the acromion (The location of the humeral head relative to the glenoid can be appreciated with rotation of the upper arm).
• Mark this site as the starting point for the injection.
• Prep the skin in this region using alcohol and povidone-iodine, Put on sterile gloves.
• If available, an assistant can spray the area with ethyl chloride spray to provide superficial analgesia just prior to needle insertion.
• The needle should be directed anteriorly toward the coracoid process advancing slowly aiming slightly medial.
• The needle aimed superiorly at a 10 to 15° angle to end up just distal to the undersurface of the acromion process.
• Once in the subacromial space, aspirate first to ensure that the tip of the needle is not intravascular followed by injection of the prepared lidocaine-corticosteroid mixture.

The same starting point has been used for both glenohumeral injection and subacromial injection.

Anterior Approach

• Patient is placed in the seated position with their affected upper extremity resting comfortably at their side on the chair’s arm rest with the shoulder in a neutral or slightly externally rotated (approximately 15 to 20°) position.
• Examine the anterior aspect of the shoulder looking for evidence of overlying cellulitis (avoid placing the needle through any area of potential infection).
• Palpate the coracoid process and the humeral head (rotation of the upper extremity can help localize the humeral head relative to the glenoid).
• Mark the starting point for the injection just medial to the humeral head, 5 to 10 mm lateral to the tip of the coracoid process.
• The needle aimed superiorly at a 10 to 15° angle to end up just distal to the undersurface of the acromion process.

Reference

1. Campbel’s Operative Orthopaedics 13th Book
2. Emergency Room Orthopaedic Procedures, An Illustrative Guide for the House Officer book
3. Clinical Tests for the Musculoskeletal System, Third Edition book.
4. Mark Dutton, Pt . Dutton’s Orthopaedic Examination, Evaluation, And Intervention, 3rd Edition Book.
5. Millers Review of Orthopaedics, 7th Edition Book.
6. Huu MN, Dung TT, Ngoc TM, Tran Q, Le Khanh T, et al. (2017) Corticoid Injection for Subacromial Impingement Syndrome Treatment. Glob J Medical Clin Case Rep 4(4): 080-082. DOI: 10.17352/2455-5282.000055
7. Youtube: https://www.youtube.com/watch?v=nq50AveOCz0