Early Closure of Growth Plate Due to Avascular Necrosis of the Femoral Head After Displaced Fracture of the Femoral Neck in Children

Abstract

To investigate the effect of autogenous tissue engineering of growth plates in the treatment of growth plate injury. The growth plate chondrocytes were cultured from the iliac crest of 3-week-old rabbits by mechanical shearing and type II collagenase digestion. After in vitro development, the chondrocytes were seeded on the allogeneic decalcified bone matrix. After being mixed in culture for one week, the chondrocytes were implanted into the defects of the medial growth plate at the upper end of the right tibia; the left tibia was not treated. Dynamic X-ray photography was used to measure the shortening and angular changes in the lower extremity. The H & E and collagen1 immunohistochemical staining were used to observe the in vivo outcomes of the growth plate. There was a slight deformity in the right tibia of group A and group B on the 2nd and 3rd week after the operation, however, there was no significant difference between the three groups (P > 0.05). After that, the right tibia of group B and group C had progressive severe shortening and angulation deformity, while the right tibia of group A had no significant increase in deformity. There was a significant difference between group A, B and C at each time point (P < 0.05). In group A, the normal growth plate structure from collagen-1 immunohistochemical staining was recovered, while in group B and C the damaged area was repaired by new bone tissue. Autogenous tissue engineering of the growth plate can effectively prevent limb deformity after acute growth plate injury. The implanted tissue engineered growth plate can produce a columnar structure; cells can express type II collagen.