Scaphotrapeziotrapezoidal Joint Injection

Other Names

Key Points

Palpation Guidance vs Ultrasound Guidance

Palpation guided injection of the STT joint have not been well described
- Author commentary: unlikely you can predictably enter joint by palpation guidance
Smith et al: palmer approach with ultrasound was 100% accurate, palpation guided dorsal approach was 80%^[2]

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

Equipment

Ultrasound Findings

Using the palmer approach, the palm should be up
Place the transducer in long axis with the thumb metacarpal
- Slide the transducer proximally to identify the CMC joint
- As you continue proximal translation, the STT joint comes into view
- Center the joint space between the scaphoid and trapezium

Technique Palmer Approach: Long Axis, Out-of-plane

Patient position
- Seated or supine
- Palm up
Transducer position
- Long axis to the thumb metacarpal
Needle Approach/ Orientation
- Out of plane
- Radial to ulnar
- Use a step down technique
Target
- Palmer aspect of STT joint, specifically the scaphoid-trapezium space
Pearls and Pitfalls
- Anesthetic will disperse through other metacarpal joints
- Avoid the superficial palmer branch of the radial artery

Technique Dorsal Approach: Long Axis, Out-of-plane

Patient position
- Seated or supine
- Palm down
Transducer position
- Radial to the extensor pollicis longus tendon, anatomic snuffbox
- Long axis to the thumb metacarpal
Needle Approach/ Orientation
- Out of plane
- Radial to ulnar
- Use a step down technique
Target
- Dorsal aspect of STT joint, specifically the scaphoid-trapezium space
Pearls and Pitfalls
- Identify and avoid the superficial branch of the radial nerve
- Identify and avoid the dorsal carpal arch

Technique Dorsal Approach: Palpation Guided

Patient position
- Seated or supine
- Palm down
Identify Landmarks
- Palpate the STT joint just radial to the extensor pollicis longus tendon at the base of the anatomic snuff box.
- Palpate the radial artery to determine course
- Mobilize the thumb metacarpal-phalangeal joint to ensure that the STT joint is being palpated and not the carpometacarpal joint.
Needle Approach/ Orientation
- Advance the needle perpendicular to the skin in a palmar direction until the capsule is felt to be penetrated by feeling a distinct puncture.
Target
- Dorsal aspect of STT joint
Pearls and Pitfalls
- Take care to avoid puncture of the radial artery

↑ Anakwe, R. E., and S. D. Middleton. "Osteoarthritis at the base of the thumb." BMJ 343 (2011).
↑ ^2.0 ^2.1 Smith J, Brault JS, Rizzo M, Sayeed YA, Finnoff JT. Accuracy of sonographically guided and palpation guided scaphotrapeziotrapezoid joint injections. J Ultrasound Med. 2011;30(11): 1509–1515.
↑ ^3.0 ^3.1 Malanga, Gerard, and Kenneth Mautner. Atlas of ultrasound-guided musculoskeletal injections. McGraw-Hill, 2014.
↑ Smith et al.. Accuracy of sonographically guided and palpation guided scaphotrapeziotrapezoid joint injections. Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine 2011. 30:1509-15. PMID: 22039023. DOI

Created by:

John Kiel on 22 January 2024 15:28:58

Authors:

Last edited:

22 January 2024 16:38:24

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