The tibial polyethylene insert , whether modular or nonmodular, usually can be disengaged from the underlying metal tibial tray. Removal of the tibial polyethylene insert creates a space that allows easier exposure of the remaining implants and sometimes can reduce the amount of dissection required to gain access to the tibial and femoral components. Removal of the polyethylene insert of most modular knees (and even nonmodular knees) can be achieved by levering the tibial insert out of the tray with an osteotome. Many manufacturers also have implant-specific tools to remove the modular polyethylene from the tibial tray. The surgeon should be aware that special screws or pins may secure the tibial insert to the tray; having manufacturer-specific screwdrivers or pin-grasping instruments available is helpful. When difficulty is encountered removing the tibial polyethylene from the tray, an osteotome or saw can be used to divide the tibial polyethylene, after which it can be removed from the metal tray.

Studying the specific locking mechanism of the implant that will be removed ahead of surgery, understanding optimal methods of disassembly, and having specific required tools available can save time and simplify implant removal.

Removal of the femoral component begins by dividing the implant-cement interface (for cemented implants) or the implant-bone interface (for uncemented implants). For cemented implants, the best instruments are osteotomes or ultrasonic instruments, and for uncemented implants the best instruments are power saws, thin osteotomes, or thin high-speed cutting instruments. The anterior flange interface, distal interface, and chamfer interfaces usually all can be accessed without difficulty. Fixation pegs at the distal interface may impede access to a small central part of that interface. Narrow osteotomes or saws can be used to work along the chamfer interfaces or in the narrow spaces between fixation pegs of the distal interface. It is best to work from both the medial and lateral sides of the implant separately; this reduces the distance that the sharp instruments travel while out of sight beneath the implant and thus reduces the likelihood of the instrument wandering away from the implant and creating excessive bone loss. The posterior condylar interfaces are hardest to access, but often there is osteolysis or little fixation at this interface. Dividing this interface is best done with narrow, thin osteotomes, special angled osteotomes, or a thin saw. Once the implant interfaces are divided, the femoral component may be removed with a company-specific or generic extractor that grasps the femoral implant and allows extraction with a slap hammer. Alternatively the implant can be tapped off of the femur gently using a metal punch against the anterior flange of the implant.

Posterior stabilized implants with a closed posterior cam box present interfaces that are difficult to access. Special care needs to be taken to remove these implants gently to avoid fracturing a condyle away from the femur.

Most tibial components can be removed by passing a saw or osteotome beneath the tibial tray, then levering the tibial component away from the underlying bone. As is the case for femoral components, cemented implants usually can be removed by passing an osteotome between the implant and the cement. When the metal implant is roughened, porous coated or precoated, the cement may not readily separate from the metal. In this circumstance the cement can be divided with a saw or ultrasonic instruments to facilitate implant removal. Uncemented implants usually can be removed by dividing the bone-implant interface with a saw. When pegs, central stems, or keels prevent the surgeon from passing instruments from anterior to posterior, to divide posterior interfaces of the tibial implant, good medial exposure with external tibial rotation often allows instruments to be passed in a medial to lateral direction posterior to the pegs or keel. Care should be taken to protect soft tissues in the popliteal fossa area. A reciprocating saw, with the smooth side of the saw directed posteriorly, may help protect posterior soft tissue structures.