Conservative treatment for a ruptured extensor tendon on the dorsum of the proximal phalanges of the thumb (mallet thumb).

Of 35 patients with mallet thumb, 25 received conservative coil-splint immobilization treatment. Those who received treatment were able to extend the interphalangeal joints to at least 0 degrees with the exception of four patients. The number of patients who did not respond to the treatment was greater in those 30 years of age or older compared with those 29 years old or younger, but there was no statistically significant difference. Satisfactory extension was observed in 12 patients who received treatment within 2 weeks after sustaining injuries. Four of 10 patients who received treatment 2 weeks or later after the injuries demonstrated poor results. The preferred treatment for mallet thumb is primary surgical repair. However, conservative treatment should be the first choice if there is no skin wound or the conditions at first consultation are not appropriate for surgery.