Growth of a costochondral graft in the rat temporomandibular joint.

The aim of this study was to examine the growth and adaptation of costochondral grafts in the temporomandibular joint (TMJ). An autogenous rib section with either a short, intermediate, or long cartilaginous end was transplanted to replace the right mandibular condyle in 20-day-old rats. At 40 days, the mandibular halves with the short cartilage transplants were shorter than the contralateral halves, whereas the two sides did not differ in length in the rats with the intermediate transplant. The mandibular halves with the longest cartilaginous transplants initially were longer than the contralateral ones. The glenoid fossa was located more laterally as compared with the unoperated side. The results provide evidence that costochondral transplants do not adapt to the functional conditions of the TMJ and that the amount of cartilage in the graft has some bearing on its growth capacity.