HEALING OF PLATED FEMORAL OSTEOTOMIES IN DOGS - A MECHANICAL STUDY USING A NEW TEST METHOD

We investigated changes in whole bone flexural rigidity during healing of plated osteotomized beagle femora. Using a recently developed mech anical method, healing femora and their intact contralateral controls were tested in non-destructive bending in 24 planes at 15 degree angul ar increments. The elliptical distributions of flexural rigidity were used to define 4 parameters which describe the mechanical status of a healing bone relative to its control. Plates of 3 different rigidities were used in 21 beagles; 6 for 2 months and 15 for 6 months. 2 healin g efficiency parameters, describing bone rigidity, indicated that plat ed femora may never reach the rigidity of their controls. One of the p arameters, describing bone asymmetry, showed that changes in bone asym metry occurred early in the healing process. Results at 6 months showe d no differences in rigidity and asymmetry of bones plated with the di fferent plates. This is attributed to antagonistic effects of axial an d flexural rigidities of the plates on bone healing. Our results indic ate that the method may be useful for bone healing research.