Dowel pinning for metacarpal and metatarsal fractures in dogs

Abstract

To evaluate a dowel pinning technique for metacarpal and metatarsal fractures in dogs. Medical records of 13 dogs with complete clinical and radiographic follow-up examinations after a median observation time of 5months were evaluated retrospectively. Assessment included fracture data, number of stabilized bones versus number of fractured bones and parameters of internal fixation including postoperative axial alignment and position of implants assessed on serial radiographs. Complications during the healing period and the final radiographic and functional outcome were analysed in relation to the details of fracture fixation. Most dogs in this study (mean age: 2.9years, mean weight: 9.9kg) had fractures of three or four bones, and fractures were closed in all but one dog. All fractures involved the metacarpal/metatarsal body, and all but five were transverse. The size of Kirschner wires used for dowel pinning ranged from 0.8 to 2.0mm, and the length in relation to bone length ranged from 39 to 91%. Axial alignment of internal fixation was and remained anatomically correct and the dowel pins remained in place in all but one dog. This dog had open metatarsal fractures and dowel pinning was contraindicated. Additionally, the Kirschner wires perforated the cortex of the proximal segments, which resulted in implant migration, malunion and residual lameness. The other dogs achieved complete functional union even though seven of 13 dogs developed radiographic signs of synostosis. Although the number of dogs in this study was small, dowel pinning was shown to be technically straightforward, inexpensive and effective for surgical repair of canine metacarpal and metatarsal bone fractures. Further studies should focus on the need for and duration of additional external coaptation.