Effect of repair time on radiographic and biomechanical characteristics of rabbit tibia in osteoperforated bone

In this experimental study, the radiographic and biomechanical characteristics of osteoperforated rabbit tibia during bone repair period were investigated. Using dental drills, 2 mm holes were drilled at the mid-shaft of right tibia in 12 New Zealand white rabbits. The left tibia was intact and selected as the control. X-rays of the left and right tibias were taken right after surgery and then every two weeks up to six weeks. Radiographic densities of the medial, central and lateral sites of the holes were measured. Every two weeks from the surgery, four of the animals were sacrificed. Tibias were removed and ultimate loads, elongations at ultimate loads, and stiffness of both right and left bones were measured. Results revealed that during repair process, radiographic density of the test leg at lateral and medial sites, in contrast to the control, changed significantly (p<0.05) and reached the controls’ levels after six weeks (p>0.05). Radiographic density in the medial site of right tibia was significantly different (p<0.05) from the same site in the control leg. But, it approached the same density as that of the control leg after four weeks (p>0.05). Ultimate load, elongation at ultimate load, and stiffness were not significantly different from those of the control leg (p>0.05). Cancellus bone repairs faster than compact bone. Radiographic density characteristic was more sensitive to repair compared to mechanical characteristics.