Formation of Bone by Periosteum After Experimental Infarction by Embolism of Femur in Rabbits

Abstract

Some authors ascribe osteogenic potentialities to the periosteum and feel that it is important for normal nutrition of bone and for repair of injuries to the cortex. Others have observed no nutritional disturbance or decrease in bone regeneration in the absence of periosteum or after experimental fractures, partial resections and drill holes. There is also no uniformity among observations made after transplanting this tissue. Failure of bone formation by the periosteum does not demonstrate that it may not occur under proper conditions. It, therefore, seems desirable to accumulate more data on periosteal osteogenesis and to devise better methods for studying changes in bone.

Infarcts have been produced in the femur of young and adult rabbits by injecting through its nutrient arteries a particulate suspension of charcoal in 5% gum acacia. Interference with the blood supply to the femur by interrupting the vessels outside the cortex did not, however, produce noteworthy changes except in very young rabbits. The bones were removed for examination from 20 hours to 150 days after operation, fixed in 10% formalin and decalcified by 4% nitric acid. Histologic sections were then cut from celloidin blocks and stained with hematoxylin and eosin.

The charcoal emboli produced marked necrosis of the medullary tissues and inner one-fourth to one-half of the cortex. This was followed by the formation of a wide layer of compact new bone outside the cortex that seemed to envelop the infarcted portion of the shaft and it was always well delimited from the pre-existing living bone by a narrow straight line of demarcation. Its thickness varied from a few layers of bone cells to that of the original cortex, and the outer edge was irregular. More marked osteogenesis and revascularization of necrotic bone occurred at the attachment of muscles and tendons. In some regions there was necrosis of the entire thickness of the cortex without new bone formation as if some of the soft tissues about the femur had been infarcted inadvertently. The structure of the new periosteal bone was essentially like that of the cortex but its haversian systems were more irregularly arranged and the bone cells varied in size and shape.