A customized patient-specific orthopaedic instrument assembly includes a customized patient-specific cutting block which has a bone-facing surface having a customized patient-specific negative contour configured to receive a portion of an anterior side of a bone of a knee of a patient that has a corresponding contour. The cutting block also has a outer surface is opposite the bone-facing surface, at least one guide pin hole, and a cutting guide. An ankle brace can be secured externally to an ankle of the patient, and an external alignment rod has a first end which can be secured to the customized patient-specific cutting block and a second end which can be secured to the ankle brace.
