Mallet fracture is a common injury, with the Ishiguro procedure a useful and effective therapeutic technique. We report on our treatment of 16 patients 13 of whom were followed up. Fractures were classified and evaluated by radiographs according to Wehbe's method. Clinical results were assessed according to Kanie's criterion (composed of extension lag and arc of DIPj). We also measured “Dorsal Gap”.Clinical results were excellent in 4, good in 5, fair in 1, and poor in 3. According to the separate criterion of DIPj arc, results were exellent in 9, good in 2, fair in 0, and poor in 2. According to extension lag, results were excellent in 4, good in 6, fair in 2, and poor in 1. From the above it can be seen that overall clinical results depend more on swayed extension lag than the DIPj arc. Since extension lag is correlated with the size of bone fragments and “Dorsal Gap” it is important to reduce the “Dorsal Gap” as much as possible when reducing a Mallet fracture.