Principles of Revision Total Knee Arthroplasty Issada Thongtrangan, Patrick Yoon, and Khaled J. Saleh Revision total knee arthroplasty (TKA) is considered by some to be the most difficult procedure in the field of orthopaedic surgery. Good results can be consis- tently obtained if a meticulous and methodic ap- proach is taken by the provider. Keeping the goals of treatment in mind as well as possible compounding factors specific to each individual case will aid in achieving optimal results. This article presents the schema one should undergo in a revision TKA, from mechanism of failure to preoperative assessment as well as intra-operative technique and a discussion on rehabilitation principles. © 2003 Elsevier Inc. All rights reserved. R evision total knee arthroplasty (TKA) is one of the most demanding and complex pro- cedures in orthopedic surgery. The goals of treatment—to obtain adequate exposure, to re- move components with minimal bone loss, to restore a normal joint line, to correct anatomic alignment, to balance the flexion-extension gap and ligaments, and to successfully implant a new stable and durable construct—are often difficult to achieve (Table 1). Factors that compound this difficulty include scarring from one or more previous operations, the presence of infection, soft tissue contracture, damage to ligamentous support, and the loss of bone stock in terms of both quantity and quality. This section will briefly identify etiologies of failure, preoperative planning, surgical technique, and complications of revision TKA. Mechanism of Failure It is very important to determine why the pri- mary TKA failed so the same mistake is not repeated at the revision surgery. The mechanism of failure can be determined by a careful history, physical examination, and radiographic and lab- oratory investigations. The most common mech- anisms of failure are outlined in Table 2. Preoperative Assessment The goals of taking the history of a patient are to determine if the patient’s symptoms are consis- tent with failed TKA and to exclude conditions in which revision TKA may need to be delayed, or is contraindicated, such as systemic infection, Charcot arthropathy, neuromuscular disease, or poor medical condition. Pain history is very im- portant because constant pain often indicates infection, while pain with activity suggests a me- chanical problem. “Start-up pain” that then de- creases after a relatively short period of activity may occur in cases of mechanical loosening that stabilizes with weight bearing. The surgeon should be particularly suspicious of an underly- ing problem when there is new pain occurring after a pain-free interval after surgery. Eliciting a history of grinding or mechanical crepitance suggests excessive polyethylene liner wear, and, possibly, even direct contact between the femo- ral component and tibial tray. Obtaining the previous operative report, and determining the size and manufacturer of the components is also necessary. Different prostheses may have propri- etary extraction devices, and the surgeon may determine the particular modular features of a given prosthesis (eg, stems attached via Morse taper or threads, tibial liner extracted medial- lateral versus anterior-posterior). Physical examination includes the assessment of range of motion, ligamentous instability, lower limb alignment, and patellofemoral track- ing. The presence of any fixed contractures may alert the surgeon to potential exposure difficul- From the Department of Orthopaedic Surgery, University of Min- nesota, Minneapolis, MN. Address reprint requests to Khaled J. Saleh, MD, MSc, FRCS(C), Associate Professor, Department of Orthopaedic Surgery, University of Minnesota, 2450 Riverside Ave. South, R200, Minneapolis, MN 55455. E-mail: saleh002@tc.umn.edu Unrestricted research funding has been received from Stryker Howmedica Osteonics to support this work. © 2003 Elsevier Inc. All rights reserved. 1045-4527/03/1403-0002$30.00/0 doi:10.1053/S0145-4527(03)00048-8 142 Seminars in Arthroplasty, Vol 14, No 3 ( July), 2003: pp 142-147