RADIOGRAPHIC, DENSITOMETRIC, AND BIOMECHANICAL EFFECTS OF RECOMBINANTCANINE SOMATOTROPIN IN AN UNSTABLE OSTECTOMY GAP MODEL OF BONE HEALING IN DOGS

Objective - To determine the effect of recombinant canine somatotropin (STH) on radiographic, densitometric, and biomechanical aspects of bo ne healing using an unstable ostectomy gap model. Study Design - After an ostectomy of the midshaft radius, bone healing was evaluated over an 8-week period in control dogs (n = 4) and dogs receiving recombinan t canine STH (n = 4). Animals or Sample Population - Eight sexually in tact female Beagle dogs, 4 to 5 years old. Methods - Bone healing was evaluated by qualitative and quantitative evaluation of serial radiogr aphs every 2 weeks. Terminal dual-energy x-ray absorptiometry and thre e-point bending biomechanical testing were also performed. Results - D ogs receiving STH had more advanced radiographic healing of ostectomy sites. Bone area, bone mineral content, and bone density were two to f ive times greater at the ostectomy sites of treated dogs. Ultimate loa d at failure and stiffness were three and five times greater in dogs r eceiving STH. Conclusions - Using the ostectomy gap model, recombinant canine STH enhanced the radiographic, densitometric, and biomechanica l aspects of bone healing in dogs. Clinical Relevance - Dogs at risk f or delayed healing of fractures may benefit from treatment with recomb inant canine STH. (C) Copyright 1998 by The American College of Veteri nary Surgeons.