strontium-radioisotopes and Bone-Diseases--Metabolic

We examined the effect of rigid plate application on the radiostrontium clearance of the intact canine femur at 6 months. We examined each of the component surgical steps. We calculated the clearance both for the whole bone and for each of the five transverse sections of the whole bone. Screw application, but not drilling, increased the clearance in the segment about the screw holes. Plate application produced an increase in the segment beneath the plate as well as around the screws and in the whole bone. These changes are accomplished not only by an absolute increase in clearance to the middle three segments, but by a relative diminution in clearance by the most proximal and distal segments. The histomorphometric changes in long bones following rigid plating may be accompanied by regional increases in bone blood flow.

Topics: Animals; Bone and Bones; Bone Diseases, Metabolic; Bone Plates; Bone Screws; Dogs; Femur; Fracture Fixation, Internal; Ischemia; Postoperative Complications; Radionuclide Imaging; Regional Blood Flow; Strontium Radioisotopes

The effects of each of the surgical stages involved in compression plating on the development of cortical thinning and porosity were assessed in the intact midshaft, stress-shielded femoral segments of adult mongrel dogs 6 months postoperatively. The data were evaluated in terms of a postsurgical tetracycline-based measure of remodeling and terminal 85Sr clearance (SrC) values for the plated segments of bone. Drilling had no effect on any parameter. Screw application was associated with minimal cortical thinning (p less than 0.05), while plate fixation clearly promoted thinning (p less than 0.01) and porosity (p less than 0.05). The percentage of labeled osteons, a measure of remodeling activity, increased only after plate fixation (p less than 0.05), and the labeling patterns suggested that most osteons had formed during the first 4 postsurgical months. That none of these changes were correlated with the 6-month SrC values suggests that the development of plate-induced osteopenia involves disparate histomorphometric time constants, rather than lack of any association.

Topics: Animals; Bone and Bones; Bone Diseases, Metabolic; Bone Plates; Bone Screws; Dogs; Femur; Fracture Fixation, Internal; Ischemia; Postoperative Complications; Regional Blood Flow; Strontium Radioisotopes; Wound Healing

Topics: Absorption; Administration, Oral; Bone and Bones; Bone Diseases, Metabolic; Calcium; Calcium Radioisotopes; Humans; Injections, Intravenous; Strontium Radioisotopes; Whole-Body Counting

Topics: Bone and Bones; Bone Diseases, Metabolic; Calcium Radioisotopes; Humans; Kinetics; Radioactive Tracers; Radioisotopes; Radionuclide Imaging; Strontium Radioisotopes