Abstract
Objective This study aimed to evaluate implant-induced osteoporosis (IIO) development in toy
breed dogs treated using internal fixation with digital radiographs as the index of
pixel values.
Study Design There were 226 cases (236 limbs) of toy breed dogs with radial–ulnar fractures. Pixel
values were measured on radiographs immediately, 2 weeks and 1 to 12 months after
surgery. The ratio of pixel values (PVR) represented the bone mineral areal density
based on the humeral condyle in the same image. The dogs were grouped based on the
fixation methods, age and status of destabilization.
Results There was a significant decrease in the PVR at 1 to 12 months postoperatively for
all cases. There were not any significant differences in PVR of antebrachial fractures
between those repaired with plates using locking head screws, cortex screws or a combination
of locking and cortex screws. Implant-induced osteoporosis persisted at 1 to 12 months
postoperatively in dogs aged ≧6 months, while the PVR increased after 3 months in
dogs aged <6 months. Based on the destabilization method, there was a significant
increase in the PVR at 3 months in the plate removal group.
Conclusion This study suggests that IIO occurs in small dogs treated with plates and screws.
Moreover, patients aged < 6 months showed an early postoperative recovery of bone
mineral areal density. Further, screw and plate removal could contribute to the recovery
of bone mineral areal density.
Keywords implant-induced osteoporosis - radial-ulnar fractures - toy breed dogs - internal
fixation - destabilization
