Shoulder Injections: Techniques, Indications, and Post-Procedure Care

What is the technique for shoulder injection?

Shoulder injections involve the precise delivery of therapeutic substances into specific anatomical spaces or structures within the shoulder joint complex to alleviate pain and inflammation. The technique varies significantly based on the target site, requiring meticulous anatomical knowledge, sterile practice, and often, image guidance for optimal accuracy and patient safety.

Understanding Shoulder Injections: An Overview

Shoulder injections are a common medical procedure performed to diagnose and treat various musculoskeletal conditions affecting the shoulder joint. These interventions aim to deliver medication directly to the site of pathology, often providing more targeted relief than oral medications and with fewer systemic side effects.

• Why are they performed? (Indications): Injections are typically considered for conditions causing pain, inflammation, and reduced range of motion, such as:
  • Rotator cuff tendinopathy or tears (e.g., supraspinatus tendinopathy)
  • Subacromial impingement syndrome
  • Bursitis (e.g., subacromial bursitis)
  • Osteoarthritis of the glenohumeral or acromioclavicular (AC) joint
  • Adhesive capsulitis (frozen shoulder)
  • Biceps tendinopathy
• What substances are injected? (Types of Injections): The most common substances include:
  • Corticosteroids (e.g., triamcinolone, methylprednisolone): Potent anti-inflammatory agents that reduce swelling and pain. Often combined with a local anesthetic (e.g., lidocaine, bupivacaine).
  • Hyaluronic Acid (Viscosupplementation): Used for osteoarthritis to lubricate the joint and provide cushioning.
  • Platelet-Rich Plasma (PRP): Derived from the patient's own blood, thought to promote healing of tendons and ligaments.
  • Local Anesthetics: Primarily for diagnostic purposes (e.g., to confirm the source of pain) or immediate pain relief.
• Who performs them? (Qualified Personnel): Shoulder injections must only be performed by qualified medical professionals, including orthopedic surgeons, sports medicine physicians, physiatrists (physical medicine and rehabilitation specialists), rheumatologists, and specially trained advanced practice providers.

Essential Pre-Injection Considerations

Before any injection, a thorough assessment is paramount to ensure patient safety and optimize outcomes.

• Patient Assessment and History: A detailed medical history, physical examination, and review of imaging (X-rays, MRI, ultrasound) are crucial to confirm the diagnosis, identify contraindications, and determine the most appropriate injection site and substance.
• Informed Consent: The patient must be fully informed about the procedure, including its benefits, potential risks (e.g., infection, bleeding, allergic reaction, temporary increase in pain, skin atrophy, tendon rupture), alternative treatments, and post-injection care.
• Anatomical Knowledge: A profound understanding of shoulder anatomy, including bony landmarks, joint capsules, bursae, tendons, nerves, and blood vessels, is critical for precise needle placement and avoiding complications.
• Sterile Environment Preparation: Maintaining strict aseptic technique is non-negotiable to prevent infection. This involves:
  • Hand hygiene: Thorough hand washing or alcohol-based rub.
  • Sterile gloves: Donning sterile gloves.
  • Skin preparation: Cleaning the injection site with an antiseptic solution (e.g., chlorhexidine or povidone-iodine) using a concentric scrubbing motion. Allowing the solution to dry.
  • Sterile drapes: Draping the area to create a sterile field.
  • Sterile instruments: Using sterile needles, syringes, and medication vials.

Common Shoulder Injection Sites and Techniques

The approach to shoulder injection is highly site-specific. While manual palpation can guide some injections, image guidance (ultrasound or fluoroscopy) is increasingly preferred and often considered the standard of care due to its superior accuracy, ability to visualize anatomical structures, and avoidance of neurovascular structures.

Subacromial Space Injection

• Indications: Subacromial impingement, rotator cuff tendinopathy, subacromial bursitis.
• Patient Positioning: Sitting or supine, with the arm relaxed and slightly internally rotated.
• Landmarks (Posterior Approach - Common): The posterior aspect of the acromion and the posterolateral corner of the acromion.
• Technique:
  • Needle Insertion: A 22-25 gauge, 1.5-inch needle is typically used. The needle is inserted just inferior and medial to the posterolateral corner of the acromion.
  • Angle and Depth: The needle is advanced anteriorly and slightly superiorly, aiming towards the coracoid process, parallel to the floor (if patient is supine) or slightly angled towards the acromion. The goal is to enter the subacromial bursa, which is a potential space. A "loss of resistance" may be felt as the needle enters the bursa.
  • Aspiration: Before injecting, gently aspirate to ensure no blood return (indicating a vessel puncture) or synovial fluid.
  • Injection: Slowly inject the medication. Resistance indicates incorrect placement (e.g., within a tendon).

Glenohumeral Joint Injection

• Indications: Glenohumeral osteoarthritis, adhesive capsulitis, inflammatory arthritis.
• Patient Positioning: Supine or sitting, arm relaxed.
• Landmarks:
  • Posterior Approach (Most Common): Coracoid process, humeral head, and glenoid rim. The "soft spot" inferior to the posterior acromion and medial to the humeral head.
  • Anterior Approach: Coracoid process, humeral head, and deltopectoral groove.
• Technique (Posterior Approach):
  • Needle Insertion: A 20-22 gauge, 1.5-2 inch needle. Inserted into the "soft spot," aiming towards the coracoid process.
  • Angle and Depth: Angle the needle medially and slightly anteriorly, aiming for the glenoid rim. The needle should advance until it contacts bone (glenoid) then be withdrawn slightly (1-2mm) to ensure it's within the joint capsule.
  • Aspiration: Aspirate for blood or synovial fluid.
  • Injection: Slowly inject. Easy flow confirms intra-articular placement. Resistance suggests impingement on cartilage or capsule.

Acromioclavicular (AC) Joint Injection

• Indications: AC joint arthritis, AC joint sprain.
• Patient Positioning: Sitting or supine.
• Landmarks: Palpable prominence of the AC joint, located at the superior aspect of the shoulder where the clavicle meets the acromion.
• Technique:
  • Needle Insertion: A 25-27 gauge, 0.5-1 inch needle. Inserted directly into the palpable joint line.
  • Angle and Depth: Angle slightly inferiorly. The joint space is very narrow.
  • Aspiration: Aspirate.
  • Injection: Inject slowly.

Bicipital Groove (Long Head of Biceps Tendon Sheath) Injection

• Indications: Biceps tendinopathy.
• Patient Positioning: Sitting or supine, with the arm slightly externally rotated to make the groove more accessible.
• Landmarks: Bicipital groove, located on the anterior aspect of the humeral head, palpable between the greater and lesser tuberosities.
• Technique:
  • Needle Insertion: A 25-27 gauge, 1-1.5 inch needle. Inserted directly into the bicipital groove.
  • Angle and Depth: Angle slightly inferiorly, aiming to stay within the tendon sheath and not into the tendon itself.
  • Aspiration: Aspirate.
  • Injection: Inject slowly. The medication should flow easily along the tendon sheath.

Post-Injection Care and Expectations

Proper post-injection care is vital for maximizing the benefits and minimizing complications.

• Immediate Post-Injection Advice:
  • Apply a small bandage.
  • Avoid strenuous activity of the injected shoulder for 24-48 hours.
  • Ice application may help reduce initial discomfort or swelling.
  • Advise the patient that pain may temporarily worsen before improving (especially with corticosteroids).
• Activity Modification: Depending on the substance injected and the condition treated, specific activity restrictions may be advised for several days to weeks.
• Potential Side Effects: Monitor for signs of infection (increased pain, redness, swelling, fever), allergic reaction, or persistent pain.
• Follow-up: A follow-up appointment is often scheduled to assess the effectiveness of the injection and plan further management, which may include physical therapy.

Important Considerations and Limitations

While shoulder injections can be highly effective, they are not without limitations and should be part of a broader treatment plan.

• Not a Cure-All: Injections primarily address symptoms (pain, inflammation) rather than the underlying cause of the pathology. They often serve as a bridge to allow for more effective physical therapy and rehabilitation.
• Risks and Contraindications:
  • Infection: Although rare, it's a serious complication.
  • Bleeding/Hematoma: Especially in patients on anticoagulants.
  • Nerve Damage: Though uncommon, can occur with improper technique.
  • Tendon Rupture: A rare but reported complication, particularly with repeated corticosteroid injections into weight-bearing tendons.
  • Allergic Reaction: To the injectate or local anesthetic.
  • Facial Flushing/Insomnia: Common transient side effects of corticosteroids.
  • Diabetic Blood Sugar Spike: Corticosteroids can temporarily elevate blood glucose levels.
  • Contraindications: Active infection at the site, uncontrolled bleeding disorders, severe joint destruction (may require surgery), or known allergy to injectate.
• Importance of Rehabilitation: For most shoulder conditions, an injection is only one component of a comprehensive treatment plan. It should ideally be followed by a structured physical therapy program to restore strength, mobility, and function, addressing the root cause of the dysfunction.
• Ethical Considerations: The frequency of injections, especially corticosteroids, should be limited due to potential adverse effects on local tissues.

Conclusion: A Component of Comprehensive Shoulder Care

Understanding the technique for shoulder injection is crucial for healthcare professionals and patients alike. These procedures, when performed by skilled practitioners with meticulous attention to detail and sterile technique, can provide significant pain relief and facilitate rehabilitation for a wide range of shoulder conditions. However, they are best viewed as a valuable tool within a broader, evidence-based approach to managing shoulder pain and dysfunction, emphasizing the importance of accurate diagnosis, patient education, and a commitment to restoring long-term shoulder health and function.