Treatment of osteomyelitis in New Zealand white rabbit using impregnated biomaterials with gentamicin: in vivo study outcome of bacterial study and micro-computed topography evaluation

INTRODUCTION: Treatment of osteomyelitis is still a major challenge in orthopaedic field. New Zealand White rabbit is acceptable experimental model described to develop effective local delivery of antibiotics osteomyelitis treatment as it can mimics the disease process in human. The objective of the study is to evaluate the outcome treatment of osteomyelitis in rabbit femur with impregnated Hydroxyappatite Gentamicin. Evaluation at stipulated durations using microCT Skyscan 1176 system. MATERIALS & METHODS: Osteomyelitis is created by inoculation of Staphylococcus aureus ATCC 25923 into rabbit’s distal femur. The rabbit were divided with 3, 6, 12, 26 week assessments. The response of the biomaterials (hydroxyapatite) impregnated with gentamicin against the infection were evaluated through micro-computed topography using Skyscan 1176 system.The bone analysis data were obtained by the software provided by Skyscan 1176 system. The distal femoral shaft were scanned using A1 1mm filter with 18µm pixel resolutions. Bacterial study of culture and sensitivity, coagulase test, catalase test and gram stain were done to determine the treatment is effective. RESULTS: The data of bone analysis were for tissue volume (TV), bone surface (BS), bone volume (BV), and trabecular thickness (Tb.Th) in all groups were illustrated at Table 1. The bone healing noted in the treated group. The results showed no bacterial were grow in the agar and all test were negative at 26 weeks interval. Table 1 showing the bone analysis through Skyscan1176 system. Week & parameter Tissue volume (mm3) Bone volume (mm3) Bone surface(mm3) Trabecular thickness (mm) 3 W SHAM 156.692 66.962 399.351 0.045 3W post treatment 168.051 84.762 500.962 0.405 6W post treatment 409.204 104.952 1001.135 0.456 12 W treatment 590.716 113.485 1520.599 0.549 26w post treatment 635.955 124.958 1558.096 0.723 DISCUSSIONS: Osteomyelitic changes were noted in all rabbit after inoculation of bacteria at week three and six. The micro-computed topographic analysis at 3, 6, 12 and 26 weeks of interval, showed increase bone parameters in treated femur. The bone volume (BV) was increased with value 124.96 mm3 compared to sham group (no treatment given) with bone volume 66.96 mm3. The density of biomaterials was decreased with duration of studies. This data showed that micro-computed topography studies is capable to provide information of bone microstructures in rapid and non-destructive way. The findings showed that impregnated biomaterials with gentamicin have potential to be used in osteomyelitis infection. CONCLUSION: Computed topography results showed at 26 weeks of treatment, the impregnated biomaterials have a potential in treatment of osteomyelitis