Microvascular morphology of bone in arthrosis. Scanning electron microscopy in rabbits

The morphology of the bone microvasculature in rabbit arthrosis was studied by scanning electron microscopy (SEM) and related to changes in intraosseous pressure (IOP) and phlebographic appearance. Unilateral gonarthrosis was induced in 34 rabbits by immobilization of one knee in extension with a plastic splint for 5 weeks. Bilateral IOP recording in a subgroup of 12 rabbits demonstrated hypertension in arthrosis of 22 +/- 2.9 mmHg compared with 11 +/- 4.7 mmHg in control knees. Intraosseous phlebography in 13 rabbits showed a dilated vascular bed with prolonged clearance of contrast media. The morphology of normal microvasculature by SEM of intravascular methyl methacrylate casts in 9 rabbits was characterized by well-defined and well-demarcated sinusoids with only a few arteriovenous shunts, whereas in arthrosis substantial changes included fusion of sinusoids, leakage of cast material through the sinusoid walls, and development of numerous shunts. The study demonstrated profound microvascular morphologic changes that may reflect a vascular genesis for some of the bone changes in arthrosis.