Techniques for Injection of the Scaphotrapezium-Trapezoid Joint Without Image Guidance

Area of Science:

• Orthopedics
• Anatomy
• Interventional Procedures

Background:

• Scaphotrapezium-trapezoid (STT) joint arthritis is a common cause of wrist pain.
• Corticosteroid injections are a frequent conservative treatment for STT joint arthritis.
• Standardized palpation-guided injection techniques for the STT joint are not well-documented.

Purpose of the Study:

• To establish a standardized, reproducible, and safe palpation-guided injection method for the STT joint.
• To minimize risks to local anatomic structures during STT joint injections.

Main Methods:

• Six fresh-frozen cadaveric upper extremity specimens were utilized.
• Dorsal, volar, and radial approaches to the STT joint were assessed.
• Needle placement, angulation, and proximity to neurovascular structures were documented using fluoroscopy and dissection.

Main Results:

• The dorsal approach involved a 90º needle angle, inserted one-third the distance from the second metacarpal base to Lister tubercle, with no neurovascular compromise.
• The volar approach (65º angle) risked the volar branch of the radial artery.
• The radial approach (60º angle) risked the dorsal branch of the radial artery.

Conclusions:

• The dorsal approach provides safe and accurate access to the STT joint for palpation-guided injections.
• This technique is particularly useful in clinical settings lacking fluoroscopy or ultrasound guidance.