# Ultrasound-Guided Peripheral Joint and Bursal Injections

## Introduction

**Ultrasound (US)-guided injections** have become a cornerstone of physiatric procedural practice, offering real-time visualization of needle placement, improved accuracy, and reduced complication rates compared to landmark-based techniques. Peripheral joint and bursal injections are among the most commonly performed musculoskeletal procedures, targeting conditions such as **osteoarthritis, inflammatory arthritis, adhesive capsulitis**, and **bursitis** with corticosteroid, hyaluronic acid, or other injectates.

## Advantages of Ultrasound Guidance

### Clinical Benefits

**Accuracy**: US guidance improves injection accuracy from 50-80% (landmark) to >95%. Real-time visualization of needle trajectory and injectate spread. Identification of adjacent neurovascular structures to avoid injury. Reduced number of needle passes and patient discomfort.

Ability to aspirate effusions under direct visualization. Documentation of pre-procedural pathology and post-procedural injectate placement.

### Compared to Fluoroscopy

No ionizing radiation exposure. Portable and available at point of care. Dynamic assessment of tendons, ligaments, and soft tissues. Lower cost per procedure. No contrast agent required for confirmation.

## Ultrasound Fundamentals for Injections

### Transducer Selection

**High-frequency linear probe** (10-18 MHz): Superficial structures (wrist, hand, ankle, bursae). **Low-frequency curvilinear probe** (5-8 MHz): Deep structures (hip, shoulder deep compartments). Hockey stick probe: Small joints (fingers, toes).

### Needle Visualization Approaches

**In-plane**: Needle parallel to transducer; entire needle shaft and tip visible. **Out-of-plane**: Needle perpendicular to transducer; cross-sectional view of needle. In-plane approach preferred for most peripheral joint and bursal injections. **Needle tip confirmation**: Hydrodissection with small aliquot of injectate or jiggling technique.

![Ultrasound image demonstrating in-plane needle approach for a joint injection with visible needle tip](images/us-guided-injection-needle-visualization.png)

## Shoulder Injections

### Glenohumeral Joint

**Posterior approach**: Most common US-guided approach. Patient seated with arm across body; transducer over posterior joint. Needle inserted in-plane targeting the glenohumeral joint recess. Indications: adhesive capsulitis, glenohumeral osteoarthritis, inflammatory arthritis. Injectate: corticosteroid (e.g., 40 mg triamcinolone) with local anesthetic.

### Subacromial-Subdeltoid Bursa

**Lateral approach** with transducer over the lateral acromion. Target the hypoechoic bursal space between the deltoid and rotator cuff. Indications: subacromial bursitis, impingement syndrome. Confirm injectate spread within the bursal planes.

### Acromioclavicular Joint

Small joint; US guidance significantly improves accuracy over landmark. Superior approach with transducer over the AC joint. Indications: AC joint arthropathy, distal clavicle osteolysis.

## Hip Injections

### Hip Joint (Femoroacetabular)

**Anterior approach** with curvilinear probe over the anterior hip. Target the anterior capsular recess at the femoral head-neck junction. Avoid the femoral neurovascular bundle (medial to target). Indications: hip osteoarthritis, femoroacetabular impingement, labral pathology. US accuracy comparable to fluoroscopy for intra-articular placement.

### Greater Trochanteric Bursa

Lateral decubitus position with affected side up. Target the anechoic bursal space over the greater trochanter. Indications: greater trochanteric pain syndrome, trochanteric bursitis. May also target individual gluteal tendon pathology.

## Knee Injections

### Knee Joint

**Suprapatellar approach**: Transducer longitudinal over the suprapatellar recess. Patient supine with knee slightly flexed; needle in-plane from lateral or medial. Indications: knee osteoarthritis, inflammatory arthritis, effusion aspiration. US-guided accuracy >95% versus 75-85% landmark-guided.

### Pes Anserine Bursa

Medial proximal tibia; superficial location. Indications: pes anserine bursitis/tendinopathy. Small-volume injection (1-2 mL corticosteroid with local anesthetic).

![Ultrasound-guided suprapatellar knee injection showing needle tip within the suprapatellar recess](images/us-guided-knee-injection.png)

## Other Peripheral Joint and Bursal Injections

### Ankle and Foot

**Tibiotalar joint**: Anterior approach between tibialis anterior and extensor hallucis longus. **Subtalar joint**: Lateral approach at the sinus tarsi. **First MTP joint**: Dorsomedial approach; common for gout and osteoarthritis. **Retrocalcaneal bursa**: Deep to the Achilles tendon at calcaneal insertion.

### Wrist and Hand

**Radiocarpal joint**: Dorsal approach between extensor compartments. **First CMC joint**: Common site for osteoarthritis injections. **De Quervain tenosynovitis**: First dorsal compartment tendon sheath injection. **Trigger finger**: Flexor tendon sheath injection.

### Elbow

**Elbow joint**: Lateral approach targeting the radiocapitellar recess. **Olecranon bursa**: Superficial; aspiration and injection for bursitis.

## Injectates

**Corticosteroids**: Triamcinolone acetonide (20-40 mg) or methylprednisolone; anti-inflammatory. **Local anesthetics**: Lidocaine 1% or bupivacaine 0.25% for immediate pain relief and diagnostic confirmation. **Hyaluronic acid**: Viscosupplementation for knee and hip osteoarthritis. **Platelet-rich plasma (PRP)**: Emerging evidence for select indications. **Normal saline**: Joint distension (e.g., hydrodilatation for adhesive capsulitis).

| Target | Approach | Transducer | Key Landmark | Common Indication |
|--------|----------|-----------|-------------|-------------------|
| Glenohumeral joint | Posterior, in-plane | Linear | Posterior joint recess | OA, adhesive capsulitis |
| Subacromial bursa | Lateral | Linear | Space between deltoid and cuff | Bursitis, impingement |
| AC joint | Superior | Linear | AC joint line | AC arthropathy |
| Hip joint | Anterior | Curvilinear | Femoral head-neck junction | OA, FAI |
| Knee (suprapatellar) | Longitudinal, lateral/medial | Linear | Suprapatellar recess | OA, effusion aspiration |
| Greater trochanteric bursa | Lateral | Linear | Greater trochanter | Trochanteric pain syndrome |
| First CMC joint | Dorsal | Linear/hockey stick | First CMC joint line | OA |

## Complications and Safety

**Infection**: Rare (<1:10,000); strict aseptic technique mandatory. Post-injection flare: Transient (24-48 hours); common with crystalline corticosteroids. Skin depigmentation and subcutaneous atrophy with superficial corticosteroid deposition. Tendon weakening with peritendinous corticosteroid injections (avoid direct tendon injection).

Limit corticosteroid injections to **3-4 per joint per year** to minimize cartilage effects. Hyperglycemia in diabetic patients (transient, 48-72 hours).

![Ultrasound image of greater trochanteric bursal injection with injectate spread visible in the bursal space](images/us-guided-trochanteric-bursa-injection.png)

## Key Clinical Pearls

1. Ultrasound guidance improves injection accuracy to greater than 95% for most peripheral joints and bursae, with the greatest benefit in anatomically challenging targets such as the hip and small joints of the hand and foot. 2. The in-plane needle approach is preferred for most injections as it allows continuous visualization of the entire needle shaft and tip, reducing the risk of inadvertent neurovascular injury. 3. Corticosteroid injections should generally be limited to 3-4 per joint per year, and direct injection into tendon substance should be avoided to prevent tendon weakening and rupture. 4. Diagnostic accuracy is enhanced by combining the injection with local anesthetic to assess pain relief, helping confirm the targeted structure as the pain generator.

## References

1. Finnoff JT, et al. "Accuracy of Ultrasound-Guided Versus Unguided Injections: A Systematic Review." *PM R*. 2010;2(2):100-107.
2. Berkoff DJ, et al. "Clinical Utility of Ultrasound-Guided Musculoskeletal Injections." *Am J Phys Med Rehabil*. 2012;91(7):607-612.
3. Daniels EW, et al. "Validity of Landmark-Guided and Ultrasound-Guided Injections of the Glenohumeral Joint." *Am J Sports Med*. 2008;36(10):1924-1929.
4. Sibbitt WL Jr, et al. "Does Ultrasound Guidance Improve the Outcomes of Arthrocentesis and Corticosteroid Injection of the Knee?" *Scand J Rheumatol*. 2012;41(1):66-72.