Reimplantation of growth plate chondrocyte cultures in central growth plate defects: Part II. Surgical experimentation in rabbits.

An original and reliable technique to culture growth plate chondrocytes was developed to obtain an abundant amount of mature and functional chondrocytes. Growth plates were provided from the epiphysis of 3-week-old rabbits. Isolation of the chondrocytes was optimized by the use of trypsin and collagenase. The culture was realized according to the following conditions: seeding at 20,000 or 30,000/cm2 on type I collagen substrate and in Ham F-12 medium without a supplementation of glucose or growth factors. After 7 days of culture, the implantation was to be carried out. Different implantation substrates were evaluated in vivo. Agar turned out to be the only substrate to provide strong and healthy chondrocytes 21 days after the grafting. Then implantation was tested on large iliac resections in rabbits to check whether an enchondral ossification occurred with the culture. Poor results were obtained because of an early disappearance of the cultured chondrocytes. In an other experimentation, the culture was implanted into surgically created defects in the growth plate area. In this case, the culture did produce an epiphysiodesis. However, the 6-week postoperative histological examination showed that the implant remained viable, continued to maintain a proteoglycanrich matrix, and began to organize in ordered columns of mature chondrocytes.