The effects of low-dose radiotherapy on fresh osteochondral allografts: An experimental study in rabbits

Abstract

Objective: The aim of this study was to investigate the effects of low-dose fractionated radiotherapy oncartilage degeneration after distal femoral fresh massive osteochondral allograft transplantation.Methods: Twenty-four New Zealand White rabbits were divided into three groups of 8 rabbits each. Allrabbits underwent distal femoral medial condyle fresh massive osteochondral allograft transplantationfrom California rabbits. The group 1 underwent transplantation without any preliminary process. Thegroup 2 underwent fractionated local radiotherapy of 100 cGy forŞve days starting on the transplantation day. The group 3 included the rabbits to which the grafts transplanted after radiating in vitroby a single dose radiation of 1500 cGy. The hosts were sacriŞced twelve weeks later. Anteroposterior andlateral radiographs were taken. Synovial tissue, cartilaginous tissue, and subchondral bone were assessedhistopathologically.Results: Nonunion was present in three cases of group 2 and one of group 3 in which cartilage degeneration was more severe. Synovial hypertrophy and pannus formation were more obvious in nonradiated rabbits. Hypocellularity and necrosis of the subchondral bone were rare in group 2. Morecartilage tissue impairment was present in group 3 compared to group 1.Conclusion: In osteochondral massive allograft transplantations, the immune reaction of the host couldbe precluded with radiotherapy, and the side-effects can be prevented by low-dose fractionated regimen.The total dose of fractionated radiotherapy for an immune suppression should be adjusted not to damagethe cartilage tissue, but to avoid articular degeneration in the long term.© 2016 Turkish Association of Orthopaedics and Traumatology. Publishing services by Elsevier B.V. This isan open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).