The present invention relates to a prosthesis, such as a megaprosthesis, for a joint replacement or any segmental bone deficit. In particular, the present invention relates to a stem for a prosthesis having threads on at least part of an outer surface thereof. A prosthesis, such as a megaprothesis, is also provided. The prosthesis contains the threaded stem and a modular body engaged to the stem. The modular body contains a bone replace segment or a replacement joint, such as replacement knee joint, hip joint, shoulder joint, wrist joint, ankle joint, elbow joint, joints of the hand, joints of the foot, etc.

Knee implant systems and methods for implantation or use in a knee joint, are disclosed. A knee implant system can include at femoral component having a femur-contacting surface and an opposing articulation surface, and proximal, distal, anterior and posterior portion. The femoral component can include a medial condyle and a lateral condyle, where each of the condyles define respective distal-most points and have substantially equal widths. The width of each of the condyles can define respective condyle midpoints, where the distal-most points can be located laterally from the midpoints. The femoral component can include a trochlear groove that can define a distal-most sulcus point located halfway between the distal-most point of the medial condyle and the distal-most point of the lateral condyle.

Provided is an artificial knee joint implant with which the balance between ligaments can be properly adjusted. An artificial knee joint implant includes a plurality of types of tibial plates-having tibia-side sliding faces that slide against femoral components and respectively having at least either the tibia-side sliding faces at different positions with respect to a tibia in a state where the tibial plates are fixed to a tibial tray attached to a tibia, or the tibia-side sliding faces in different shapes.

A femoral assembly includes a femoral component that includes condylar portions and an anterior flange portion. The condylar portions and anterior flange portion together define an outer side of the femoral component for articulating with a tibial prosthesis and an inner bone facing side opposite the outer side. The inner bone facing side defines five intersecting component inner surfaces that each extend from a lateral side of the femoral component to a medial side thereof. A femoral augment includes condylar portions and an anterior flange portion. The condylar portions and anterior flange portion together define an outer side of the femoral augment comprised of five intersecting augment outer surfaces and an inner side comprising no more than three intersecting augment inner surfaces. The augment outer surfaces correspond to the component inner surfaces of the femoral component. The augment inner surfaces correspond to resected surfaces of a distal femur.

A knee joint prosthesis is configured to move between an extended position and a flexion position. The knee joint prosthesis includes a femoral component configured to be mounted to a femur, and a tibial component configured to be mounted to a tibia. The tibial component is configured to engage the femoral component to form the knee joint prosthesis. A post is fixedly connected to one of the femoral component and the tibial component and has a helical surface at a terminal end thereof. A recess is defined on the other of the femoral component and the tibial component and has a helical surface. The helical surfaces of the post and recess are configured to engage in order to cause relative rotation between the femoral and tibial components as the knee joint prosthesis moves between the extended and flexion positions.

There is provided a ligament reconstruction type artificial knee joint that can exert a function of an anterior cruciate ligament in an original knee joint.

In an artificial knee joint 1 used in a total knee replacement, the artificial knee joint 1 includes: a femur member 10 mounted on a femur distal end DT; a tibia member 20 mounted on a tibia proximal end PE; and an artificial ligament 30 coupling the tibia member 20 and the femur member 10 together. One end of the artificial ligament 30 is coupled to a position where once an anterior cruciate ligament ACL exists in a knee replaced for the artificial knee joint 1 on an inside of a lateral condyle of the femur member 10, and the other end of the artificial ligament 30 is coupled to a position where once the anterior cruciate ligament ACL exists in the knee replaced for the artificial knee joint 1 on an upper side of the tibia member 20.

An artificial knee joint, which includes an upper surface at which a post performs a motion relative to a cam of the thighbone coupling member, is configured such that a radius of curvature of an upper curved surface extending posteriorly from the upper surface is larger than that of a lower curved surface, so as to prevent the cam of the thighbone coupling member from deviating from an inflection point existing between the upper curved surface and the lower curved surface, and is configured such that the upper surface is inclined at a predetermined angle, so as to allow the thighbone coupling member to be restored while naturally descending along the upper surface even when the thighbone coupling member is dislocated, thereby increasing a jump distance without increasing an amount of bone to be cut.

A modular knee joint prosthesis is configured to move between an extended position and a flexion position. The modular knee joint prosthesis includes a femoral component that is configured to be mounted to a femur. The femoral component has a first cutout or opening in a central region thereof for receiving a femoral insert. The modular knee joint prosthesis also includes a tibial component that is configured to (i) be mounted either directly or indirectly to a tibia, and (ii) engage the femoral component. The tibial component has a second cutout or opening in a central region thereof for receiving a tibial insert. A kit includes the modular knee joint prosthesis, at least two of the femoral inserts having different geometries, and at least two of the tibial inserts having different geometries.

A method for placing an implant on a patient in a robotic surgical procedure using a robotic system. During the robotic surgical procedure, a navigation system tracks the patient. The navigation system also provides information to the robotic system to guide movement of a cutting tool to remove material from the patient such that a cut surface is created to receive the implant. The implant is then robotically placed on the cut surface.

A ligament assembly (2) comprising a resilient element (20) connected to a bone anchor (4) and a ligament (18), the resilient element (20) acting m a cantilever and resisting toads transmitted between the bone anchor (4) and the ligament (18) by virtue of the resistance to bending of the resilient element. The ligament (18) may comprise an artificial ligament (18) which is adapted to replace a human or animal ligament. The resilient element (20) may comprise a spiral spring and may act as a biasing element/shock absorber operatively coupled to the artificial ligament (18) to control the effective stiffness of the artificial ligament (18). Consequently, the resilient element (20) enables an effective stiffness of the artificial ligament (18) to be achieved that more closely approximates the stiffness of a natural ligament.