A novel closed reduction with extension block and flexion block using Kirschner wires and microscrew fixation for mallet fractures.
BACKGROUND
Some patients with mallet fractures who undergo extension block pinning complain of exposed wires, which delay their return to sports and causes inconvenience while performing tasks that require the use of hands during the early postoperative period. The purpose of this retrospective study was to present and evaluate a novel surgical procedure for mallet fractures.


METHODS
We treated 20 patients (14 males and six females; mean age, 38.4 years; range 17-68 years) with displaced mallet fractures involving >30 % of the articular surface using the closed reduction and microscrew fixation between January 2009 and January 2012. The distal interphalangeal joint (DIP) joint was immobilized with a splint for 1-3 weeks on an individual case basis. According to Wehbe and Schneider's classification, there were 12 type IB, six type IIB, and two type IA fractures. The mean follow-up duration was 12.6 months (range 6-31 months).


RESULTS
Bone union was achieved in all patients within a mean period of 6.8 weeks, with no incidence of infection, skin necrosis, permanent nail deformity, or secondary osteoarthritis. Only two complications-temporary nail ridging in one patient and a dorsal bump caused by the screw in one patient-were observed. Minimum postoperative displacement was observed in one patient, for whom immobilization with a splint was continued for 4 weeks. Articular incongruity was <1.0 mm in four patients and 1.0-2.0 mm in two patients. Mean DIP joint extension loss was 6.5° and mean flexion was 67.8°. The surgical outcomes were excellent in seven patients, good in nine, and fair in four according to Crawford's evaluation criteria.


CONCLUSIONS
Our novel surgical procedure combining closed reduction with extension block and flexion block using Kirschner wires and microscrew fixation produces good clinical results with relatively few complications.
Department of Orthopaedic Surgery, National Printing Bureau Tokyo Hospital, 2-3-6 Nishigahara, Kita-ku, Tokyo 114-0024, Japan; Department of Orthopaedic and Spinal Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. Electronic address: shimura.orth@tmd.ac.jp.
Haruhiko
H
Shimura
Department of Orthopaedic and Spinal Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. Electronic address: wakabayashi.orth@tmd.ac.jp.
Yoshiaki
Y
Wakabayashi
Department of Clinical Anatomy, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. Electronic address: nimura.orj@tmd.ac.jp.
Akimoto
A
Nimura
D000293:Adolescent; D000328:Adult; D000368:Aged; D001863:Bone Screws; D001864:Bone Wires; D005260:Female; D005383:Finger Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005384:Finger Joint / Q000503:physiopathology / Q000601:surgery; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D017102:Fracture Healing; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008904:Miniaturization; D011184:Postoperative Period; D011474:Prosthesis Design; D011859:Radiography; D016059:Range of Motion, Articular; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult