Biomechanical Analysis of Bone Graft Treated With Pasteurization or Cryotherapy Using Liquid Nitrogen: A Study Using Sheep Bone Model

Osteosarcoma is a common primary malignancy of the bone. Osteosarcoma prognosis improves tremendously when chemotherapy is given in adjunct to surgical intervention. Limb reconstruction with sterilized autologous bone graft stabilized by orthopaedics implants has become a choice of treatment, but the biomechanical property of the bone treated with such sterilization method is a point of concern as a graft with inferior biomechanical property might lead to graft failure. This study compares the biomechanical properties of the bones treated with cryotherapy using liquid nitrogen and pasteurization in the form of four-point bending compression tests. Six sheep tibia bones were used for each group of treatment with one control group where no treatment was given. In the four-point bending test, osteotomy was performed at the tibia; the proximal tibia was treated with liquid nitrogen and pasteurization respectively. The treated bone is then reconstructed with the corresponding distal bone with locking plate and screws (Jiangsu Trauhiu Medical Instrument Co. Ltd., Changzhou, China). The four-point bending test was performed with an Electropulse® E3000 universal testing machine (Instron®, High Wycombe, United Kingdom) and results in the form of maximum compressive load, stress, and strain were collected. Photographic analysis of the fracture location and pattern were documented and analysed. We found that both methods of sterilization did not alter the biomechanical properties of the treated bone to the extent of statistical significance in comparison with the control group. However, other factors such as histological changes post treatment, equipment availability, and long-term outcome must be considered.