Histomorphometric Assesment of Fracture Healing in Contaminated Segmental Fracture after Sterilization using Microwave Irradiation: An experimental study on Wistar rats

Abstract

Open fractures with large bone fragment is major problems. Preservation of bone fragment is essential for fracture healing however infection due to contaminated fragment is a challenging threat. Restoration of contaminated bone fragments requires prior sterilization to prevent infection. A 7-minute microwave irradiation has been proven sterilized a contaminated bone fragment however the effect of irradiation toward incorporation to normal bone has not been established. This study investigates the effect of microwave irradiation toward fracture healing in 16 Wistar rats with segmentally contaminated fracture. The rats randomly assigned into two groups. In control group the segmental fragment was directly reimplanted and stabilized using intramedullary K wire while in treatment group the bone fragment was inoculated with Staphylococcus Aureus ATCC 25923 and exposed to 7 minutes microwave irradiation prior to reimplantation and K wire stabilization. At 2nd and 4th week, healing process was assessed using histomorphometric analysis (total fibrous tissue area, cartilage formation and woven bone area). At week 2, there is significant differences in formation of cartilage (p = 0.010) and woven bone (p = 0.004) between control and treatment group with treatment group has smaller size. At week 4, there is no statistically significant difference found between the treatment and control groups. Interval between week 2 and week 4 is the ideal time to compare normal process of fracture healing to fracture healing under treatment in Wistar rat. Microwave irradiation serve as a means to eliminate the infection yet preserve the nonorganic environment that eventually delivers conducive environment for fracture healing.