Implant assemblies, systems, kits, and methods for replacing a knee joint may include a universal femoral trial component for preparing and trialing a femoral bone of a patient to receive a plurality of different femoral implant types. The universal femoral trial component may be configured to receive any of a plurality of femoral bone preparation attachments and any of a plurality of femoral trial attachments in order to facilitate the preparation and trialing of the femoral bone to receive the plurality of different femoral implant types.

A system for converting a first joint prosthesis to a second joint prosthesis in-situ includes a plurality of inserts having a bone interface side and a component facing side and a plurality of articulating components having a cavity configured to receive at least one of the plurality of inserts. The plurality of inserts may be unicompartmental, bicompartmental, or tricompartmental. The inserts may be made of metal and may have a bone contacting surface made of a porous metal. The plurality of articulating components may be unicompartmental, bicompartmental, or tricompartmental. The articulating components may be sized and shaped to cover one or more of the plurality of bone interface components and span a distance therebetween. The articulating components may be made of a polymer.

A method and system for femoral condylar resection arthroplasty of the knee, which preserves the undamaged meniscus on top of the tibial plateau, whether by arthroscopy or arthrotomy, and only replaces the damaged area of the femoral condyle. In one embodiment, only the distal femoral condyle is replaced and the posterior femoral condyle remains intact. In another embodiment, both the distal and posterior femoral condyle are replaced. The method and system include providing a combined, one-piece Intra-condylar insert and distal femoral cutting block, and placing the intercondylar insert between articular surfaces of a distal femoral condyle and a tibial plateau with the knee in extension. The method and system also includes a box retractor having four right angle blades, two for medial structures and two for lateral structures. The blades are at two depths, shallow and deep. The components of the system are preferably of plastic material.

A method for removing an implant attached to a bone during revision joint replacement surgery includes a library of implant models. A series of surface points are collected on the implant with a digitizer. A best match is computed between the collected surface points and an implant model in the library of implant models to register the position of the implant model to the implant. A location is computed of a material-implant interface based on the geometry of the implant model and the registered position of the implant model. Material is removed at the material-implant interface to separate the implant from the bone. A computer-assisted surgical system is provided for performing the method.

A method and system for femoral condylar resection arthroplasty of the knee, which preserves the undamaged meniscus, whether by arthroscopy arthrotomy, and only replaces the damaged area of the femoral condyle. In one embodiment, only the distal femoral condyle is replaced and the posterior femoral condyle remains intact. In another embodiment, both the distal and posterior femoral condyle are replaced. The method and system include placing an intercondylar insert between articular surfaces of a distal femoral condyle and a tibial plateau with the knee in extension. The method and system also includes a box retractor having four right angle blades, two for medial structures and two for lateral structures. The blades are at two depths, shallow and deep. The components of the system are preferably of plastic material. The method and system preserve the meniscus on top of the tibial plateau.

A method for removing an implant attached to a bone during revision joint replacement surgery includes a library of implant models. A series of surface points are collected on the implant with a digitizer. A best match is computed between the collected surface points and an implant model in the library of implant models to register the position of the implant model to the implant. A location is computed of a material-implant interface based on the geometry of the implant model and the registered position of the implant model. Material is removed at the material-implant interface to separate the implant from the bone. A computer-assisted surgical system is provided for performing the method.

A method for imparting tension across a human knee joint which includes a femur bone, a tibia bone, a patella bone, a patellar tendon, and ligaments, wherein the ligaments and patellar tendon are under anatomical tension to connect the femur and tibia together, creating a load-bearing articulating joint. The method includes: providing a tensioning device, including: a baseplate; a top plate; and a linkage interconnecting the baseplate and the top plate and operable to move the tensioning device between retracted and extended positions, wherein the top plate is pivotally connected to the linkage so as to be able to freely pivot about a pivot axis; positioning the tensioning device between the femur and the tibia; applying an actuating force to the linkage to move the tensioning device towards the extended position, so as to impart a controlled separating force driving the femur and tibia apart to extend the ligaments.

A method of planning a procedure to fasten an implant to a bone includes displaying a model of the bone and a model of the implant on a display device. The model implant is positioned on the model bone in a desired implant position. A first boundary volume of a first fastener configured to fasten the prosthesis to the bone is also displayed on the display device. The first boundary volume represents a range of possible positions that the first fastener may have with respect to the prosthesis when fastened to the bone. The boundary volume may be used to determine a desired size, shape, and/or positioning of the fastener with respect to the bone.

A method for guiding implantation of a first prosthetic component includes determining, using a virtual model of a joint including first and second bones, a planned orientation of the first prosthetic component in the joint, applying a valgus/varus moment to the joint at a plurality of flexion positions of the joint, and recording positional data indicative of relative positions of the first bone and the second bone at the plurality of flexion positions of the joint. The method also includes calculating estimated separation distances between the first prosthetic component and a second prosthetic component, adjusting the planned orientation of the first prosthetic component in the joint in response to an error between the estimated separation distances and one or more desired separation distances, and guiding implantation of the first prosthetic component on the first bone in accordance with the adjusted planned orientation of the first prosthetic component.

Implants include fixation features which slidingly receive fixation elements. The fixation features may be negative or positive features, such as undercut channels or posts. Examples include unicompartmental tibial trays having a ridge protruding from the bone-facing side, an undercut channel formed within the ridge. Instruments are disclosed for preparing a ridge-receiving feature in bone. Implants and fixation elements are configured for implantation without penetrating a cortical wall of a bone. Instruments and surgical methods are disclosed.