Identify problems by history and physical examination that will influence what procedure is done and how it is done. Determine if the patient has a history or physical findings of hip problems such as pain or stiffness, known arthritis, or previous fracture or osteotomy of the hip or femur. Determine if the patient has an ipsilateral tibial deformity or ankle or foot problems. These pieces of information are important to optimize the mechanical axis of the limb at operation. Learn as much as possible about the patient’s failed knee replacement. Identify the implant manufacturer, implant design, and implant sizes. Accurate and specific implant identification can be made by reviewing stickers from the actual implants that are placed in the patient’s medical record. If part of the knee implant will be retained intact at operation, all this information is essential to ensure that matching parts are available. Learn whether special design-specific instruments are available for implant extraction or disassembly. Review whether there is anything in the history or examination to suggest infection of the failed total knee arthroplasty (TKA). If so, consider preoperative evaluation with measurement of C-reactive protein level, erythrocyte sedimentation rate, knee aspiration,¹,² and radionuclide scans.

Evaluate the skin and previous skin incisions and find out if the patient has ever had problems with wound healing. Measure the knee range of motion and consider whether stiffness may make an extensile exposure necessary. Determine if there is evidence of ligamentous deficiency or knee instability. Test extensor mechanism power. Evaluate the patient’s vascular status. If significant peripheral vascular disease is a concern by history or examination, consider a preoperative vascular medicine or vascular surgery consult, or preoperative noninvasive arterial studies, or both. Ask if the patient has a history of venous thromboembolic problems; if so, plan accordingly for venous thromboembolism prophylaxis and consider whether preoperative evaluation by an internist, vascular medicine specialist, or thrombosis expert would be helpful. Consider the patient’s overall medical situation. Make arrangements for an appropriate preoperative medical evaluation and for postoperative support by specialists in internal medicine, cardiology, pulmonology, nephrology, or other medical disciplines if needed. If a large procedure is planned, and if the patient has numerous medical problems, make preoperative arrangements for a postoperative intensive care unit bed. Determine if the patient has experienced unusual bleeding or blood loss problems that may require preoperative hematologic evaluation and special arrangements with the blood bank. By having the patient evaluated in advance by specialists in other disciplines,
such as plastic surgery, vascular surgery, or internal medicine, some problems may be avoided. Equally important, if problems do occur intra- or postoperatively, the consultants can deal with them more effectively because they already know the patient. Likewise, the patient is more likely to take the problem in stride because the potential for such problems was anticipated.

Knee radiographs should include anteroposterior standing films, lateral films, and patellar skyline views, and a long-standing radiograph from hips to ankles (Fig. 63-1).³,⁴ Stress films occasionally may be helpful to determine the degree of ligament competence. Fluoroscopically positioned radiographs provide views that are perfectly tangential to the implant interface and provide the most detailed information of implant fixation status (Fig. 63-2). Combine the radiographic information with the rest of the preoperative evaluation to determine the mechanism of previous implant failure. Understanding the failure mechanism helps determine what needs to be done to correct the problem. Determine if the previous implants appear to be well-fixed or loose. Determine if the implants are well-positioned or malpositioned on an anteroposterior radiograph. Use the radiographs to determine the proper angle of femoral and tibial resection needed to restore the mechanical axis of the limb (Fig. 63-3). Use templates to estimate the bone resections needed to place the tibial and femoral components in optimal orientation (Fig. 63-4). Acetate overlay templates have mostly now been replaced by digital templates which have been shown to be effective and provide additional tools to measure angles, lengths, and alignment.⁵,⁶ Use templates over the anteroposterior and lateral radiographs to determine the approximate tibial or femoral implant sizes that will be needed. Evaluate the location and severity of tibial and femoral bone loss. Use templates to determine whether metal prosthetic augmentation or bone grafts will be needed (Fig. 63-5). Examine the distal femur carefully for subtle signs of osteolysis of the condyles, especially posteriorly (Fig. 63-6). Consider the severity of femoral and tibial bone loss and how long-term fixation will be obtained and maintained. Metaphyseal fixation with porous coated sleeves or highly porous metal cones can help achieve these goals by providing biologic fixation and a stronger implant foundation in deficient bone.⁷,⁸,⁹,¹⁰,¹¹,¹²,¹³,¹⁴ If metaphyseal fixation will be used, template the size and configuration of possible sleeves or cones (Fig. 63-7). Use templates to determine the length and diameter of planned tibial and femoral implant stems (Fig. 63-8). Determine whether offset stems are likely to be needed to compensate for unusual bone shape or bone deformity (Fig. 63-9).

Evaluate the patella. Is the implant metal backed or all polyethylene? Is it loose or well-fixed? If the patella needs to be removed, consider whether adequate bone stock remains to allow another implant to be placed. Consider whether there is evidence of tibial or femoral implant malrotation or of patellar maltracking. If the major problem is patellofemoral maltracking, consider evaluating rotation of the implants with a computed tomographic scan.¹⁵