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Ultrasound · Elbow

Radiocapitellar Joint Injection (Lateral Elbow)

elbowradiocapitellararthritissynovitis

Treats

  • Elbow arthritis
  • Lateral elbow joint pain
  • Synovitis/effusion
  • Diagnostic anesthetic

Contraindications

  • Active local skin infection at entry site (absolute)
  • Suspected septic joint (absolute — aspirate first)
  • Bacteremia (absolute)
  • Known allergy to local anesthetic, steroid, or antiseptic prep
  • Therapeutic anticoagulation — review case-by-case
  • Uncontrolled diabetes (relative)

Pre-procedure checklist

  • Confirm patient identity (two identifiers)
  • Confirm procedure, side, and site — mark with patient awake
  • Review allergies and anticoagulation
  • Confirm informed consent
  • Pre-scan to identify and trace the radial nerve and PIN around the radial neck
  • Time-out immediately before needle entry

Positioning

  • Supine; elbow flexed 20-40°; hand on abdomen; small pillow under elbow
Positioning

Probe

  • High-frequency linear probe (6-13 MHz)
Probe

Landmarking — find the view

  • Find lateral epicondyle → slide distally to radial head → tilt anteriorly to view capitellum → identify wedge-shaped joint space

The correct ultrasound view

  • Clear radial head–capitellum interface with a thin dark joint space
The correct ultrasound view

Needle corridor

  • Preferred: in-plane lateral approach with the needle parallel to the probe long-axis, advancing into the joint cleft under continuous visualization.
Needle corridor

Avoid

  • Radial nerve and its posterior interosseous nerve (PIN) branch — the PIN wraps around the radial neck through the supinator (arcade of Frohse) immediately distal to the radiocapitellar joint. Identify and trace before needle entry.
  • Radial recurrent vessels
  • Lateral ulnar collateral ligament (LUCL) — located at the posteroinferior aspect of the lateral joint; repeated needle trauma or intralesional injection risks posterolateral rotatory instability (PLRI)

Steps

  1. 1Preferred: in-plane lateral approach into the joint cleft. Out-of-plane walk-down is an alternative for clinicians comfortable with the technique.
  2. 2Test inject; inject 2-3 mL total, stopping if capsular back-pressure is felt.
  3. 3STOP IMMEDIATELY if the patient reports electric, shooting, or paresthetic sensations.

Tips

  • Walk-down (when used) intentionally uses gentle periosteal contact on the capitellum to localize the joint cleft — this is different from advancing blindly through soft tissue. Never force against articular cartilage.
  • Pronate/supinate the forearm to confirm the radial head moves while the lateral epicondyle stays stationary.
  • Limit corticosteroid to ≤ 3 per joint per year.
  • If color Doppler shows a vessel directly in the planned path, abandon and re-plan.

Resident pearls

  • Visual Orientation: Think of the joint as a “cleft” between two hills. The capitellum is the rounded hill, and the radial head is the flatter hill.
  • Native radiocapitellar joint capacity is ~1-3 mL — total injectate ≤ 3 mL. Over-distension risks capsular rupture and steroid extravasation toward the PIN/radial nerve.

Supplies

  • 5 mL Syringe
  • 22G or 25G 1.5" Needle
  • 18G Drawing Needle
  • 1% Lidocaine (1-2 mL)
  • Triamcinolone 20-40 mg OR Dexamethasone 4-10 mg
  • Alcohol Swabs (vial tops)
  • Betadine/Chloraprep
  • Sterile Gloves
  • Sterile 4x4 Gauze Pads
  • Sterile Towels & Drapes
  • Adhesive Bandage (Band-Aid)
  • Washcloth/Towel (gel cleanup)
  • Needle Disposal Safety Cap
  • Sterile probe cover & gel

Post-procedure

  • Apply a clean dressing; remove after 24 hours.
  • Local anesthetic relief for 1-4 hours; steroid begins 24-72 hours.
  • Steroid 'flare' in 2–10% — manage with ice and acetaminophen.
  • Rest the elbow 24-48 hours.
  • Return immediately for: spreading redness, swelling, fever, or disproportionate pain.
  • Diabetics: expect 50-100 mg/dL glucose rise for 3-5 days.
  • Maximum 3 injections per joint per year.