Several disorders of the shoulder that respond well to a course of injections are commonly encountered in general practice. However, they can involve separate synovial cavities of the joint so that accurate diagnosis is essential for successful treatment (see separate article Shoulder Examination). Joint injection should be considered after other therapeutic interventions such as non-steroidal anti-inflammatory drugs (NSAIDs), physical therapy, and activity modification have been tried.¹

There is currently no major evidence for the benefit of steroid injections for shoulder problems. Subacromial corticosteroid injection for rotator cuff disease and intra-articular injection for adhesive capsulitis (frozen shoulder) may be beneficial, although their effect may be small and not well-maintained.² One study carried out did not indicate that local corticosteroid injection is more effective than systemic corticosteroid injection for short-term improvement in rotator cuff disease.³

Practical demonstrations of anatomical landmarks and injection technique can be viewed in the short video footage under 'Internet and further reading' section at the end of this article.

Indications

• Glenohumeral joint injection: osteoarthritis, adhesive capsulitis, rheumatoid arthritis, rotator cuff lesions.
• Acromioclavicular joint: acromioclavicular joint problems, e.g. osteoarthritis (a common cause of shoulder pain in people aged over 50 years) and distal clavicular osteolysis.
• Subacromial injections: adhesive capsulitis, subacromial bursitis (may occur in gout, Reiter's syndrome, trauma or rheumatoid arthritis), impingement syndrome, rotator cuff tendinosis. Subacromial injections of corticosteroids are effective for improvement for rotator cuff tendonitis for up to nine months. They are also probably more effective than NSAID medication.⁴
• Bicipital groove: bicipital tendonitis (a tenosynovitis caused by strain of the long head of the biceps tendon).

Cautions

• Aseptic technique must be followed at all times.
• Before injection, aspiration should be performed to ensure that there has not been needle placement in a blood vessel.
• The injection should be performed slowly, but with consistent pressure.
• Injection directly into bone or periosteum is very painful and should be avoided.
• Following injection, patients should be warned that they might experience worsening symptoms during the first 24 to 48 hours (related to a possible steroid flare) which can be treated with ice and NSAIDs.

Glenohumeral joint

The glenohumeral joint can be injected from an anterior, posterior, or superior approach. The anterior and posterior approaches are used more often. The joint is most easily accessible with the patient sitting, the patient's arm resting comfortably at the side, and the shoulder externally rotated. Essential landmarks to palpate before performing this injection include the head of the humerus, the coracoid process, and the acromion.¹

Posterior injection into the glenohumeral joint

The needle should be inserted 1-2 cm inferior and medial to the posterolateral corner of the acromion and directed anteriorly in the direction of the coracoid process.
• The entry point is 1 cm inferior and medial to the posterior corner of the acromion.
• Put the index finger of your free hand on the coracoid process anteriorly and aim towards it up to the full depth of an 18 gauge needle.
• Use a combination of 2.5 ml of steroid combined with 1% lidocaine.
• This can be repeated at 4-6 weekly intervals but, if there is no benefit after two or three injections, then consider alternative treatment or referral.

Anterior injection into the glenohumeral joint

• Use a 2 ml syringe with 1 ml steroid solution mixed with 1 ml 1% lidocaine, with a 1 inch (blue hub) needle.
• The needle should be placed below the acromion process, 1 cm lateral to the coracoid process and immediately medial to the head of the humerus.
• Advance the needle horizontally, directed posteriorly and slightly superiorly and laterally.
• If the needle hits against bone, it should be pulled back and redirected at a slightly different angle.¹
• Following a correct injection, the patient should now have pain-free movements because of the effect of the local anaesthetic.

Subacromial bursa

Posterior injection into the subacromial bursa

• The posterior approach to the subacromial bursa is easier and generally safer.
• The entry point is 1 cm inferior and medial to the posterior corner of the acromion.
• Pass an 18 gauge needle up under the acromion to its full depth.
• Use a combination of 2.5 ml of steroid solution mixed with 1% lidocaine.
• The steroid and local anaesthetic should flow freely into the space without any resistance or significant discomfort to the patient.
• This can be repeated at 4-6 weekly intervals but, if there is no benefit after two or three injections, then consider alternative treatment or referral.
• Injecting under pressure into the tendon may cause tendon damage.

Lateral approach into the subacromial bursa

• The patient sits with the arm loosely at the side and not rotated.
• Palpate the most lateral point of the shoulder and make a thumbnail indentation about half an inch below the tip of the acromion process.
• Use 1 ml steroid mixed with 1 ml lidocaine 1% plain in a 2 ml syringe with a 1.5 inch needle.
• Advance the needle medially below the acromion process, horizontally and in a slightly posterior direction along the line of the supraspinous fossa.

Acromioclavicular joint

• Patients are placed in the supine or seated position, with the affected arm resting comfortably at their side.
• To identify the joint, palpate the clavicle distally to its termination, at which point a slight depression will be felt at the joint articulation.
• The acromioclavicular joint has a very small joint space. Therefore inject only 0.2-0.5 ml of steroid (local anaesthetic is not necessary) with a 5/8 inch needle.
• Palpate the joint space and insert the needle superiorly or anteriorly, ensuring that only the tip of the needle enters the joint space.
• The joint space may be difficult to enter because of obstruction by an osteophyte.
• With a superior approach, it is easy to push the needle too far and enter the shoulder capsule.

Bicipital tendonitis

• The patient sits with their affected arm loosely by their side and externally rotated.
• Make a thumbnail indentation directly over the most tender spot in the bicipital groove, which is easily palpated (at the anterolateral tip of the head of the humerus).
• Use a 2 ml syringe with 1 ml of steroid mixed with 1 ml of 1% lidocaine.
• Inject just below the skin mark and direct the needle at 30° in an upward direction into the bicipital groove, parallel to the groove. When the needle point enters the tendon, resistance increases sharply.
• Maintain gentle pressure on the plunger while at the same time withdrawing the needle slowly until the resistance disappears. At this point the needle is in the synovial sheath and the solution should then be injected.
• The patient should feel immediate relief.

Document references

1. Tallia AF, Cardone DA; Diagnostic and therapeutic injection of the shoulder region. Am Fam Physician. 2003 Mar 15;67(6):1271-8. [abstract]
2. Buchbinder R, Green S, Youd JM; Corticosteroid injections for shoulder pain. Cochrane Database Syst Rev. 2003;(1):CD004016. [abstract]
3. Ekeberg OM, Bautz-Holter E, Tveita EK, et al; Subacromial ultrasound guided or systemic steroid injection for rotator cuff disease: randomised double blind study. BMJ. 2009 Jan 23;338:a3112. doi: 10.1136/bmj.a3112. [abstract]
4. Arroll B, Goodyear-Smith F; Corticosteroid injections for painful shoulder: a meta-analysis. Br J Gen Pract. 2005 Mar;55(512):224-8. [abstract]

Internet and further reading

• Codsi MJ; The painful shoulder: when to inject and when to refer. Cleve Clin J Med. 2007 Jul;74(7):473-4, 477-8, 480-2 passim. [abstract]
• Shoulder Injection - Simon Moyes, Orthopaedic Surgeon, Vimeo.com website; short video
• Shoulder for Joint Injection, Limbs & Things; short video demonstrating five injection sites