Surgical Procedure for Femoral Fractures

The surgical procedures were previously reported. Briefly [21 (link),80 (link)], the animals received 2.5% isoflurane/oxygen and a subcutaneous injection of 1 mg/kg Buprenorphine (Reckitt Benckiser, Ludwigschafen am Rhein, Germany) for anesthesia before surgery. Then, the left part of the knee was bent, and an incision was made through the skin to expose the patella. The patella was then moved to the lateral side to expose the femoral condyles. A passage for the intramedullary pin was created through the distal end of the femur using a hollow needle (BD MicrolanceTM, 0.55 mm, sterile, Becton Dickinson Life Sciences, Heidelberg, Germany). This needle was removed, and then an intramedullary pin (Thermo spinal needle 17, 0.5 × 0.9 mm, Thermo Europe N. V., Leuven, Belgium) was inserted into the bone marrow cavity. After relocating the patella, the wound was carefully sutured.