Flexor Carpi Radialis Injection

Other Names

• Flexor Carpi Radialis Injection
• FCR Injection

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Background

Cross sectional view of the wrist

Key Points

• High frequency, linear transducer
• Needle: 25 gauge, 1 inch needle
• Use color doppler to avoid the radial artery

Anatomy of Flexor Carpi Radialis

• Originates at the medial epicondyle of the humerus
• Inserts on the volar base of the second, third metacarpals
• Tendon is radial to flexor retinaculum, does not pass through the carpal tunnel
• Radial artery courses lateral to the tendon

Palpation Guidance vs Ultrasound Guidance

• It is recommended that this injection be performed with ultrasound guidance
• There is no literature comparing palpation and ultrasound guidance

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Indications

• FCR Tenosynovitis

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Contraindications

• Absolute
  • Anaphylaxis to injectates
  • Overlying cellulitis, skin lesion or systemic infection
• Relative
  • Can be treated with less invasive means
  • Hyperglycemia or poorly controlled diabetes
  • Lack of symptom improvement with previous injection

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Procedure

Needle and probe position for long axis, in plane technique

Ultrasound view of long axis, in plane approach

Needle and probe position for short axis, out of plane technique

Ultrasound view of short axis, out of plane approach. Note the radial artery (A)

Equipment

• Sterile prep (i.e. chloraprep, chlorhexidine, iodine, etc)
• Gloves
• Needle: typically 21-25 gauge, 1.5 inch
• Syringe: 5-10 mL
• Gauze
• Ethyl Chloride
• Bandage
• Injectate
  • Local anesthetic
  • Corticosteroid
• Sterile probe cover

Ultrasound Findings

• FCR tendon best visualized in long axis
• Be sure to identify and avoid radial artery

Technique: Long Axis, In-Plane

• Patient Position
  • Seated or supine
  • Hand supinated, resting on a firm surface
• Transducer position
  • Long axis
• Needle Approach/ Orientation
  • In-plane
  • Proximal to distal
• Target
  • FCR tendon sheath
• Pearls and Pitfalls
  • Identify radial artery during pre-procedural scanning
  • Active wrist flexion can be used to help identify the tendon

Technique: Short Axis, Out of Plane

• Patient Position
  • Seated or supine
  • Hand supinated, resting on a firm surface
• Transducer position
  • Short axis
• Needle Approach/ Orientation
  • Out of plane
  • Proximal to distal
• Target
  • FCR tendon sheath
• Pearls and Pitfalls
  • Identify radial artery during pre-procedural scanning
  • Active wrist flexion can be used to help identify the tendon

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Aftercare

• No significant restrictions
• Can augment with ice, NSAIDS
• Consider temporary thumb spica brace

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Complications

• Skin: Subcutaneous fat atrophy, skin atrophy, skin depigmentation
• Painful local reaction
• Infection
• Hyperglycemia
• Tendon, nerve or blood vessel injury

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See Also

• Procedures Main
• Ultrasound Main
• Wrist Pain Main

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