Study On Percutaneous Epiphysiodesis Using Transphyseal Screws In Experiment

epiphysiodesis using transphyseal screws (PETS for short). We selected eight-month-old New Zealand rabbits as experimental animal whose right-hind limbs are used for operation and left-hind ones are for controL First, we inserted the 0.3cm-diameter cancdlous screw into the femoral epiphyseal plate of the rabbit's right-hind limb obliquely. Second, we performed radiology and histology examinations on the limbs at three different point which are pre-operation, at four weeks and eight weeks after operation.The pictures showed that the new bone formation decreased 2.34?.41cm and 6.24?.87cm at the later two points, respectively. At the end of four weeks, the epiphysis on distal femur decreased at 73.63 % ,while at the end of eight were 85 % and 78.83 %. The result demonstrated that PETS can slow down the epiphyseal growth effectively. We also studied the mechanism of PETS using biomechanics method on corpse bone. We proved the screw can make pressure on the epiphyseal plate which would change complying with insertion angle (the pressure would be the most strongest when the angle is 90 degree about 28 Mpa), and which was in direct ratio with the screw diameter. The pressure gradully decreased from the touch point to the round. Accordingly, perhaps the mechanism is the pressure made by the cancellous screw on the epiphyseal plate which would supply its clinical application. Compared with other methods, PETS have some advantages, thus are easy-learning, less operation trauma, safety incision. Which is relatively far from the joint so it won't damage it, less injury to the hone structure, which won't induce fracture easily.