Elastic cartilage grafting in canine radial fracture

Bone has a capability to repair itself when it is fractured. Repair involves the generation of intermediatetissues, such as fibrous connective tissue, cartilage and woven bone, before final bone healing can occur. Theprocess of cartilage-to-bone transition (CBT) is a key for the achievement of rigid bone healing duringfracture repair. We tested this potential for elastic cartilage using a long bone defect model in dog. Eightsexually intact female mongrel dogs, 4.57 ± 0.53 years old and weighing 11.48 ± 0.63 kg, were studied. Afteran ostectomy of the midshaft radius, bone healing was evaluated over an 8-week period in control dogs (n =4) and dogs in which autologous grafts of auricular cartilage were inserted into the bone defects (n = 4).Quantitative radiographic assessment was conducted every 2 weeks. Eight weeks post-operative, qualitativehistopathologic analysis was performed on the operated radii. Furthermore, histological grading was doneusing the Ulutas et al., scoring system. Experiment dogs had more advanced radiographic healing ofostectomy sites. The defects with elastic cartilage implants were bridged completely with new bony spiculesoriginated from the implants. Transformation of elastic cartilage clusters to mesenchymal connective tissueand bony spicules was obvious in the experiment group. Significant differences were observed for cellularmorphology [3 ± 0.82 (experiment) vs. 1.75 ± 0.5 (control)] and cartilage integration [2 (experiment) vs. 1(control)] at ostectomy sites between the studied groups. This study demonstrated that by using theostectomy gap model, autologous auricular cartilage enhanced the radiographic and histopathologic aspectsof bone healing in dogs.