Abstract: A kit of parts for use in unicondylar knee replacement of a patient having a femur and a tibia comprises a drill guide and an intramedullary rod, the intramedullary rod being sized to fit within the intramedullary canal of the femur of the patient. The drill guide is arranged so as to engage a distal end of the intramedullary rod to that which engages the patient's intramedullary canal, and is formed with a foot portion sized to fit between the patient's femur and tibia before any bone is removed from the femur or tibia. The drill guide provides a guide for drilling of at least one hole in the femur. A further kit of parts for use in unicondylar knee replacement of a patient having a femur and a tibia comprises a femoral component for implantation in the femur, the femoral component having a bearing surface having a radius of curvature, and a guide spoon.