Abstract
Introduction
Bending tests are commonly used to evaluate the mechanical behaviour of small animal bones. To test whole bones, it is normal that soft tissue should be removed before testing. However, cleaning the specimens might disturb the callus, interfering with the mechanical properties. This study compares mechanical properties of rat tibia between specimen with and without muscle cleaning
Materials and methods
12 male Wistar rats aged 3–4 months were used. Soft tissues including skin and muscle were removed from right tibias (Group A), whereas muscles on the left tibia were left intact (Group B). 4-point bending was used to find the ultimate load, stress and Young's modulus.
Results
All specimens displayed a basic failure pattern from load-displacement graph. Mean ultimate load of 105.2N (S.E.M.=7.60, n=12) for group A and 101.6N (S.E.M.=7.32, n=12) group B. Mean stress at failure of 281.50MPa (S.E.M.=34.98, n=12) was found for group A 288.70MPa (S.E.M.=20.83, n=12) for group B. Mean Young's modulus was 8.97GPa (S.E.M.=1.44, n=12) for group A and 10.05GPa (S.E.M=0.69, n=12) for group B. No statistical differences for any mechanical properties were found between groups for either t-test(p>0.05) or Bland-Altman plot.
Discussion
No differences in mechanical properties were found with or without soft tissue. Therefore, biomechanical testing of small specimen bending without removing muscle can be used. The advantages of this technique are reduced specimen preparation time and decreasing risk of creating a stress raiser at the callus.
