Thumb Tendons Injection

de Quervain's tenovaginitis

Causes and findings:
• Overuse of abductor pollicis longus and extensor pollicis brevis
• Pain over base of thumb and over styloid process of radius
• Occasional crepitus
• Painful: resisted abduction and extension of thumb passive flexion of thumb across palm especially with wrist in ulnar deviation (Finklestein's test)

Equipment:
Syringe - 1ml
Needle - 25G 0.5 inches (16mm) orange
Kenalog 40 - 10 mg
Lidocaine - 0.75 ml 2%
Total volume - 1 ml

Anatomy:
The abductor pollicis longus and extensor pollicis brevis usually run together
in a single sheath on the radial side of the wrist. The styloid process is always
tender so comparison should be made with the pain-free side. The two
tendons can often be seen when the thumb is held in extension, or can be
palpated at the base of the metacarpal. The aim is to slide the needle between
the two tendons and deposit the solution within the sheath.

Technique:
• Patient places hand vertically with thumb held in slight flexion
• Identify gap between the two tendons at base of first metacarpal
• Insert needle perpendicularly into gap then slide proximally between the tendons
• Inject solution as a bolus within tendon sheath

Aftercare:
The patient should rest the hand for a week with taping of the tendons. This is followed by avoidance of the provoking activity and a graded strengthening regime if necessary.

Comments:
Provided the wrist is not too swollen, a small sausage-shaped swelling can often be seen where the solution distends the tendon sheath.

Alternative approaches:
This is an area where depigmentation or subcutaneous fat atrophy can occur, especially noticeable in dark-skinned thin females. Although recovery can take place, the results might be permanent. Patient should be warned of this possibility before giving their consent. The potential risk can be minimized by injecting with hydrocortisone.