Revision Total Knee Arthroplasty: Order of Attack
Mark W. Pagnano
Having a coherent strategy in place before revision total knee arthroplasty (TKA) helps the surgeon order his or her thinking such that logical decisions can be made even if the unexpected is encountered.
Preoperative planning identifies the need for nonstandard implants and major deformities that require osteotomy or an alternative surgical technique.
Intraoperatively a methodical 3-step approach to revision TKA has proved reliable and reproducible over time: (1) reestablish the tibial platform, (2) restore balance in flexion by altering the anteroposterior (AP) size or offset of the femoral component, and (3) restore balance in extension by manipulating the joint line position proximally or distally.
In certain very difficult revision TKA cases it is not possible to fill or “gain control of” the flexion gap owing to extreme laxity, and in such cases a hinged total knee design is required.
Sterile Instruments and Implants
A complete set of the revision TKA instruments and implants from the surgeon’s manufacturer of choice, including a full complement of tibial inserts. Do not get caught intraoperatively without the full range of sizes and constraint options.
Appropriate range of augments, stems, porous metal cones, and/or metaphyseal sleeves to deal with a range of bone loss issues.
Extraction instruments to safely and efficiently remove the failed TKA as outlined in the chapter on implant removal.
Hinged total knee design available if this is a multiply revised TKA or the preoperative examination suggests marked ligamentous laxity or gross ligament incompetence.
Intraoperative fluoroscopy or intraoperative radiograph to confirm trial component position.
Detailed medical history to identify risks for wound healing or neurovascular issues
Prior wound healing issues or history of infection after other procedures
Detailed surgical history focused on lower extremity
Prior difficulties in exposure, ligament balance, and bone quality as detailed in operative notes or per patient and family
Timing and mode of failure resulting in need for this revision TKA; are there lessons to be learned from the prior failed TKA?
Observe patient standing and walking
Identify and document gait abnormalities, coronal plane deformities, foot drop, pes planovalgus, knee hyperextension, etc.
Examination of operative knee
Evaluate knee range of motion; identify and document preoperative contractures, coronal plane instability, and patellar stability.
Particular attention should be paid to ligamentous examination; look for clues to whether there is extreme laxity that might require hinged design; look for clues of excessive stiffness or woody/fibrotic tissue that will provide exposure challenges.
Examine the skin for open sores and prior incisions; treat or plan accordingly.
Determine fixation status of femur, tibia, and patella as a predictor of operative difficulty and time.
Predict the bone loss expected on the femoral, tibial, and patellar sides and prepare to encounter even more than predicted.
Assess the individual component position and determine if there are specific errors present that you deliberately wish to correct. For instance, if the tibia is in varus position with excessive posterior slope, then special effort should be made to address slope and to achieve neutral coronal alignment. If the femur is noted to be grossly undersized in the AP direction, then the revision femoral component should deliberately be sized 1 or 2 sizes larger.
Overall limb alignment can be assessed preoperatively to ensure there is not a substantial hip or foot/ankle abnormality that will cause gross malalignment if the standard revision TKA target of neutral mechanical alignment is chosen.
Bone, Implant, and Soft Tissue Techniques
A long incision that extends both slightly proximal and slightly distal to prior incisions is typically made (Figure 59.1). In most revision TKAs a long medial parapatellar arthrotomy with or without a quadriceps snip is used (Figure 59.2). The medial and lateral gutters are reestablished, and scar tissue is excised from the infrapatellar region to aid in exposure.
The modular tibial liner is removed.
The knee is typically flexed and the tibia externally rotated to deliver the tibia out from underneath the femur (Figure 59.3). The specifics of extensile exposure are presented in the following chapter.
Figure 59.1 ▪ Intraoperative photograph demonstrates the extent of prior incision (marked by arrowheads) and the typical extension of the incision proximally and distally to facilitate revision total knee replacement.
Figure 59.2 ▪ Intraoperative photograph demonstrates the typical long, medial parapatellar arthrotomy used for revision TKA.
Figure 59.3 ▪ Intraoperative photograph demonstrates the typical medial soft-tissue release and combined flexion of the knee and external rotation of the leg to obtain good exposure of the proximal tibia in revision TKA.
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