Bony mallet finger without epiphyseal plate injury in childhood.
BACKGROUND
It is commonly thought that Salter-Harris type I or II appears in mallet fingers in childhood, with S-H type III appearing in adolescence.


METHODS
We present a case of bony mallet finger in childhood. Radiographs showed a small fragment above the distal interphalangeal joint, and this fragment was separated from the dorsal epiphysis without injury to the epiphyseal plate. Open reduction and fixation were performed and bone union was achieved without complications.


CONCLUSIONS
Bony mallet finger in childhood manifests as S-H types I, II, and III in typical cases. However, it depends on narrowing of the epiphysis and the strength of the axial forces on the tip of the distal phalanx. In the case of epiphysis narrowing and only small forces affecting the region, an avulsion fracture without injury to the epiphyseal plate will occur in rare cases.


CONCLUSIONS
We presented here a rare case of a bony mallet finger in childhood without epiphyseal plate injury.
Department of Orthopaedics, Juntendo University School of Medicinel, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Cheolsun
C
Han
Department of Orthopaedics, Juntendo University School of Medicinel, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Orthopaedic Surgery, Juntendo University Shizuoka Hospital, 1129 Nagaoka, Izunokuni, Shizuoka, 410-2295, Japan. Electronic address: knaito@juntendo.ac.jp.
Kiyohito
K
Naito
Department of Orthopaedics, Juntendo University School of Medicinel, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan; Department of Orthopaedic Surgery, Juntendo University Shizuoka Hospital, 1129 Nagaoka, Izunokuni, Shizuoka, 410-2295, Japan.
Yoichi
Y
Sugiyama
Department of Orthopaedic Surgery, Juntendo University Shizuoka Hospital, 1129 Nagaoka, Izunokuni, Shizuoka, 410-2295, Japan.
Osamu
O
Obayashi
Department of Orthopaedics, Juntendo University School of Medicinel, 2-1-1, Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Kazuo
K
Kaneko
Epiphyseal line injury; Finger fracture in childhood; Mallet finger; Salter-Harris; classification