A tray and a clamp mounted adjustably on the tray and supporting a leg or other limb or simulated limb including an articulated animal joint or a joint from a cadaver, for use in instruction of and practice by surgeons in joint replacement or other orthopedic surgery. A bone mounting device for fastening a joint to an artificial bone includes an expandable engagement member that fits within a cavity formed within a bone to hold the bone securely so that a surgical procedure can be performed on the joint.