To begin place the anesthetized rat in a lateral recumbent position on the sterile surgical table. Remove the lower limb hairs with an electric shaver. Disinfect the surgical area in a circular motion with 5%iota four solution, followed by 75%alcohol.
After locating the proximal and distal femur, make a 2.5 centimeter incision along the long axis of the femur to cut through the skin tissue. Using ophthalmic forceps and tissue scissors, separate the skin layer from the fascia. Expose the lateral approach to the femur through the biceps femurs and lateral femoral muscles.
Locate the intersection of the two muscle septa and carefully separate with a disposable surgical blade along the muscle border until the femoral surface is reached. Next, apply a periosteal separator to bluntly separate the femoral surface muscles and expose the middle of the femoral diaphysis. Using a sterile marker pen, mark the area of the defect site on the mids surface of the femoral diaphysis.
Next, using an oral low speed handpiece drill a small hole perpendicular to the bone surface at the marked site, destroying the periosteum and bone cortex to depth reaching the bone marrow cavity. Expand the hole in all directions to achieve a box cavity shape. Now hold a labeled oral probe parallel to the edge of the defect to determine the defect diameter and morphology.
Suture to close the muscle and skin layers. Finally, disinfect the surgical area with 5%iota four from the inside out.
