We reviewed 31 patients at a mean of five years after mallet deformity of the finger had been treated with a thermoplastic splint. Intra-articular fractures were present in 35% of patients. Osteoarthritic changes had developed in 48%, most in association with fracture, and 29% had a swan-neck deformity. There was a loss of extension greater than 10° in 35%; the average deficit at the interphalangeal joint was 8.3° and the average flexion arc was 48.5°.

Despite these findings, patient satisfaction was generally high, with little evidence of functional impairment.