Implant-Associated Staphylococcus aureus Infection in Mice

Mice were anesthetized via inhalation isoflurane (2%). The surgical procedure was modified from previous work [49] (link), [50] (link). A skin incision was made over the right knee (Figure 1A). The distal right femur was accessed through a medial parapatellar arthrotomy with lateral displacement of the quadriceps-patellar complex (Figure 1B). After locating the femoral intercondylar notch (Figure 1B), the femoral intramedullary canal was manually reamed with a 25 gauge needle (Figure 1C). An orthopaedic-grade stainless steel Kirschner (K)-wire (diameter 0.6 mm) (Synthes) was surgically placed in a retrograde fashion and cut with 1 mm protruding into the joint space (Figure 1D). An inoculum of S. aureus in 2 µl of normal saline was pipetted into the joint space containing the cut end of the implant (Figure 1E). The quadriceps-patellar complex was reduced to the midline (Figure 1F) and the surgical site was closed with Dexon 5-0 sutures (Figure 1G). A representative radiograph demonstrates the position of the implant with good intramedually fixation of the stem and prominence of the cut surface in the joint (Figure 1H). Buprenorphine (0.1 mg/kg) was administered subcutaneously every 12 hours as an analgesic for the duration of the experiment.