An orthopedic device for preparing a knee joint for a prosthesis in a patient includes a femoral alignment guide. The femoral alignment guide has a patient-specific three-dimensional curved inner surface preoperatively configured from medical image scans of the knee joint of the patient to nestingly conform and mate and match only in one position to a corresponding three-dimensional femoral surface of a joint surface of the patient. The femoral alignment guide has a first guiding aperture corresponding to a distal portion of the femoral surface and a second guiding aperture corresponding to an anterior portion of the femoral surface.