Insert the posterior resection guide [46] into the drilled holes and tap home (Fig. 7.16 (a)). Do not hit hard because the guide can tilt.
Figure 7.16(a)
Insert a retractor to protect the MCL. Using the oscillating saw blade, excise the posterior facet of the femoral condyle. The saw blade should be bent slightly by dropping the saw to ensure it is guided by the underside of the posterior resection guide (Fig. 7.16(b)). Take care to avoid damage to the medial collateral and anterior cruciate ligaments.
Figure 7.16(b)
Remove the guide with the slap hammer [9], ensuring that it is withdrawn in line with the femoral drill guide holes so as to not damage them. (Use of the slap hammer is counterintuitive. The handle should be pushed towards the knee so as to lock the device onto the component while the hammer is used to pull the component off.) Remove the bone fragment.
There is now good access to the back of the joint and any remnants of the medial meniscus should be removed. In the region of the MCL, a small cuff of meniscus should be left to protect the MCL from the tibial component. The posterior horn should be completely removed.
