In an exemplary embodiment, the present invention provides an anchor assembly that can be used for the fixation or fastening of orthopedic devices or instruments to bone tissue. In particular, the present invention preferably provides a variable angle or fixed angle anchor assembly that is able to securely connect the orthopedic device to bone tissue even when there is a variance in the angle and position of the assembly with respect to the device. Furthermore, in an exemplary embodiment, the present invention provides an anchor assembly having a locking mechanism that will quickly and easily lock the anchor assembly with respect to the orthopedic device.