Early Results of a Modular Revision System in Total Knee Arthroplasty

Abstract

Background : The number of revision total knee arthroplasty (TKA) procedures is projected to rise dramatically over the next fifteen years. These procedures are technically more demanding than routine primary TKA. Modular component options can assist the surgeon in addressing complex reconstructions in TKA, providing customization to remedy bony deficits, deformity, malalignment and instability. We review the early clinical results of a modular revision system that offers full interchangeability enhanced with a wide array of options for augmentation, offset, and constraint as well as modular stems. Materials and Methods : A query of our practice’s arthroplasty registry revealed a consecutive series of 100 patients (101 knees) who signed an IRB-approved general research consent allowing retrospective review, and underwent total knee arthroplasty performed with the modular revision system between May 2011 and May 2012. Reconstruction constructs and components, demographic variables, pre and post-operative clinical variables, failure modes, and survivorship were analyzed. Results : At an average follow-up of 1 year (range, 0.1 to 2.2 years) there has been one aseptic failure for instability. One patient required incision and debridement of a non-healing wound. Three patients, all status-post reimplantation, failed secondary to recurrent infection, with one treated single-staged and the others undergoing another 2-staged exchange. Average ROM improved from 96.4° preoperatively to 104.8° at most recent evaluation. Average Knee Society clinical scores (0 to 100 possible) improved from 45.5 to 78.0, and function scores (0 to 100 possible) improved from 41.3 to 48.3. There have been no patient deaths during the follow-up period. Postoperative radiographs were available for review for 97 knees. Satisfactory position, fixation and alignment were observed in 92 (95%). Heterotopic ossification was observed at the lateral tibial aspect in 1 knee with CR lipped bearing. A stable radiolucency was observed around the tibial component of one knee. Minor radiolucencies were observed in femoral zones I and II and tibial zone 1 on lateral view of one knee, in tibial zones III and IV on AP view in one knee, and in tibial zone IV on AP view in one knee. Conclusion : The early results of this modular TKA revision system are promising for use in complex TKA, with only one aseptic failure observed. There has been substantial improvements in ROM and function in this cohort. Key words : Arthroplasty, Knee, Revision