Your patient can't extend his thumb IP after a distal radius fracture? He may have ruptured his EPL. If the dorsal radial tubercle has been disrupted by Colles fx (producing irregularity), EPL tendon may rupture due to added friction imposed upon it as it sits right in Listers tubercle. Ruptures occur most often between 3 weeks and 3 months following injury.
A jersey finger is an injury to the FDP tendon of the finger. The flexor tendon pulls the finger down into the palm as you contract the flexor muscles of the forearm. The injury occurs at the tip of the finger, and typically the tendon snaps back to the base of the finger or even into the palm of the hand. Often occurs in the athlete. A jersey finger can occur in non-sporting activities, but is most commonly seen in the athletic setting.