Pes Anserine Bursa Injection

Other Names

• Pes Anserine Bursa Injection

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Background

Illustration of the pes anserinus with the bursa marked in blue

Key Points

• Transducer: High Frequency Linear
• Needle: 1.5 inch, 21-22 gauge

Anatomy of the pes anserine bursa

• Pes Anserine is a tendinous confluence of the sartorius, gracilis and semitendinosus tendons
• They insert at a common point on the proximal, anteromedial tibia
• The bursa is a potential space between the tendons and underlying MCL, tibia

Palpation Guidance vs Ultrasound Guidance

• Ultrasound-guided and palpation-guided techniques have been described
• Finoff et al found diagnostic accuracy (anesthetic only) to be 92% with ultrasound guidance, 17% with palpation guidance
• Yoon et al found found diagnostic accuracy to be 100% with ultrasound guidance and 50% with palpation guidance
  • They also found US guided injections had better knee pain and function
• There are no papers currently comparing outcomes between ultrasound and palpation guidance

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Indications

• Pes Anserine Bursitis

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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

Palpation guided pes anserine bursa injection

Needle and probe position for long axis, in plane approach

Ultrasound view with needle in plane for long axis, in plane approach

Needle and probe position for short axis, in plane approach

Ultrasound view with needle in plane for short axis, in plane

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

• Transducer: high frequency, linear array
• Can be seen in both long and short axis
• Often normal with no distension from bursal fluid
• Uncommon ultrasound findings include:
  • Can see bursal distension
  • Tendon hypo echogenicity
  • Increased doppler flow/signal

Palpation Guided Technique

• Patient Position
  • Supine, leg externally rotated slightly
• Needle Approach/ Orientation
  • Distal to proximal
• Procedure
  • Palpate the area of maximal tenderness along the pes anserine
  • Aim needle relatively perpendicular to the surface of the tibia
  • When you hit the tibia, back off by 1 mm and empty syringe
  • Can redirect slightly cranially
  • You can move the needle in various directions slightly to increase diameter

Technique: Long Axis, In Plane

• Patient Position
  • Supine, hip externally rotated
  • Towel can be placed under knee
• Transducer position
  • Anatomic coronal plane/ long axis
• Needle Approach/ Orientation
  • In plane
  • Distal-to-proximal
• Target
  • Pes anserine bursa deep to tendons
  • If fluid is present, target the fluid
• Pearls and Pitfalls
  • Angle of needle approach is typically very shallow
  • Avoid injecting tendons/ MCL
  • Use doppler to avoid genicular vasculature

Technique: Short Axis, In Plane

• Patient Position
  • Supine, hip externally rotated
  • Towel can be placed under knee
• Transducer position
  • Anatomic oblique plane/ short axis
• Needle Approach/ Orientation
  • In plane
  • Distal-to-proximal
• Target
  • Pes anserine bursa deep to tendons
  • If fluid is present, target the fluid
• Pearls and Pitfalls
  • See above

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Aftercare

• No major restrictions in most cases
• Can augment with ice, NSAIDS
• Consider Knee Compression Sleeve to reduce re-accumulation/ swelling

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Complications

• Infection
• Damage to surrounding tissue

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See Also

Internal

• Procedures Main
• Ultrasound Main
• Knee Pain Main

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