Non-Traumatic Snapping Tendon on the Dorsal Aspect of the Thumb: A Diagnostic Challenge.

A snapping tendon on the dorsal aspect of the thumb is a rare condition as opposed to the common triggering on the volar aspect of the thumb. This condition is known as triggering of the extensor pollicis longus (EPL). A 21-year-old female presented with a clicking or snapping sensation that was felt on the dorsum of her thumb when it is extended. There was no history of trauma. She worked in an ice-cream parlor with repetitive scooping ice-cream motions. Her triggering immediately resolved on releasing the EPL fascia ulnar to Lister's tubercle. Upon wake-up surgery, we could immediately confirm this. We recommend dynamic ultrasound as an investigation and do not recommend MRI. The surgical method of choice is either wake-up surgery or wide-awake local anesthesia no tourniquet (WALANT) surgery.