The regenerative treatment of costal osteochondral graft implantation for partial growth arrest using a rabbit model

PURPOSE

To investigate the feasibility of cylindrical costal osteochondral graft transplantation as a novel regenerative treatment in growth arrest.

METHODS

The medial portion of the proximal tibial growth plate of 6-week-old male New Zealand White rabbits was resected to establish an experimental model of partial growth plate injury. The rabbits were divided into four groups: no-treatment, bone wax transplantation, costal chondral graft, and costal osteochondral graft groups. Radiographic and micro-computed tomography scan results were analyzed to evaluate angular deformity of the tibia and bony bridge formation at the injury site. In addition, repair of the injured growth plate cartilage was assessed histologically at 4, 8, and 12 weeks postoperatively.

RESULTS

Radiographic examination revealed that bone wax transplantation continuously decreased the medial proximal tibial angle (MPTA) while the costal chondral graft implantation reduced the decrease of MPTA at 12 weeks postoperatively. The costal osteochondral graft implantation recovered the MPTA, close to the normal. Histologically, the costal osteochondral grafts retained the MPTA in the injured site compared to costal chondral grafts. Additionally, hypertrophic chondrocytes were observed at the graft site in the costal osteochondral graft group at 12 weeks, suggesting that endochondral ossification may occur at the graft site similar to normal ossification. The fluorescence in situ hybridization analysis of osteochondral grafts transplanted from male to female rabbits indicated that they were replaced by cells of host origin.

CONCLUSION

The costal osteochondral graft can achieve regeneration without bony bridge formation in partial growth plate injury.

Assessment of the talar deformity and alignment in congenital clubfoot using three-dimensional MRI after Ponseti method

BACKGROUND

Ponseti method have been widely accepted as the initial treatment of congenital idiopathic clubfoot because its excellent primary result. On the other hand, relapses after Ponseti method are not uncommon and the cause of relapses have not been fully elucidated. We investigated detailed morphology and alignment of tarsal bones in clubfoot after Ponseti method using three-dimensional MRI analysis.

METHODS

We performed MRI with 10 patients of unilateral clubfoot at three months after Achilles tenotomy. Based on the MRI volume data, we reconstructed three-dimensional bone surface model using the marching cubes method. We evaluated the volume of the talus and navicular bone, medial and planter deviation of the talar head and neck, medial deviation of the navicular bone, and internal rotation angle of the distal tibiofibular joint.

RESULTS

In clubfoot, the volume of talus and navicular bone were significantly smaller compared with the contralateral side. Deviation of the talar head and neck varied from medially to almost the same as that on the contralateral side. The degree of deformity of the talus and alignment of the navicular bone and distal tibiofibular joint showed correlations.

CONCLUSIONS

Patients with the medial deviated talar neck might have the alignment change of navicular bone and distal tibiofibular joint. Deformity of talar neck might to be compensated by talonavicular joint and distal tibiofibular joint through the manipulation of Ponseti method.