Healing between cartilage and bone ends. An experimental study

Abstract

Whether healing or nonunion occurs at the junction between cartilage and bone was studied in an animal experimental model. The costochondral junctions of the floating ribs of rabbits were excised and the cut ends of bone and cartilage reapproximated with wire. The process of healing was then observed. Fibrocartilaginous callus formed in the first week. Beginning in the second week, this was gradually replaced by bony callus, a process which started from the medullary cavity of the bone end. The cut end of the original cartilage showed no activity. The periosteum and perichondrium became continuous at 4 weeks. The site of ossification assumed the appearance of the original costochondral junction. The gap between the original cartilage and the new cartilage disappeared when fusion occurred at 48 weeks. Osteochondral junctions at various periods after operation were subjected to disruption force until the junctions were pulled apart. The average force required to break 16 junctions was 2,738 g, and was not related to the period of healing.