There are provided various embodiments of medical instruments to perform knee surgery. In one embodiment a finned platform for mounting a cutting block is provided. The finned platform can be used don either a femor or tibia to allow for the proper cuts when performing a knee surgery. In another embodiment, a tibial trial is shown having a fin. The fin is useful to reinforce the bone to reduce the risk of fracture during bone preparation. In another embodiment, a reamer is provided having a plurality of cutting flutes. It may be desirable to utilize a guide with the reamer to allow the reamer to cut a noncircular portion of the tibial bone. In yet another embodiment, a plurality of fixation pegs are provided on the tibial implant to allow for easy removal of such implant if a revision surgery becomes necessary.