Instrumentation for use in minimally invasive unicompartmental knee replacement includes a tibial cutting guide for establishing a planar surface along a tibial plateau and a tibial stylus having an anatomic contour for controlling the depth of the planar surface along the tibial plateau. The instrumentation further comprises a posterior resection block for preparing a posterior femoral resection, with a forward portion of the posterior resection block having a configuration corresponding to the configuration of a prosthetic femoral component. Instrumentation comprising a resection block and a resurfacing guide are provided for surgically preparing a femoral condyle to receive a prosthetic femoral component. The instrumentation further includes a resurfacing guide and a resurfacing instrument for resurfacing a femoral condyle to a controlled depth. Instrumentation is provided for intramedullary alignment of femoral instruments. Also, instrumentation is provided for preparing the femur and tibia to receive fixation structure of prosthetic femoral and tibial components.