Plate fixation of tibial fractures in the rabbit. Correlation of bone strength with duration of fixation.

Bone healing after metal plate fixation of rabbit tibial osteotomies was studied in order to gain information as to the optimum time for plate removal. The fracture had regained almost normal biomechanical properties after 6 weeks. Significantly greater strength and stiffness of the healing tibiae were obtained at 12 weeks when the plate was removed after 4, 6 or 9 weeks and no further fixation was subsequently applied, compared to those plated for 12 weeks. The results indicate that a metal plate should be removed as soon as the fracture has regained normal biomechanical properties; i.e. before the stress-protecting effect has secondarily weakened the bone. The findings suggest that metal plates should be removed at an earlier stage of the healing period than is usual in clinical practice.