175 REPLACEMENT VERSUS NON-REPLACEMENT OF THE PATELLAR JOINT SURFACE IN TOTAL KNEE ARTHROPLASTY SUBSTITUIÇÃO VERSUS NÃO SUBSTITUIÇÃO DA SUPERFÍCIE ARTICULAR DA PATELA NA ARTROPLASTIA TOTAL DE JOELHO Rafael aluisio feneRich honoRio feRReiRa 1 , leonaRdo BaRRos MascaRenhas 1 , RodRigo saliM 1 , aline MiRanda feRReiRa 1 , faBRício fogagnolo 1 , MauRício KfuRi JunioR 1,2 1. Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, Department of Locomotor Biomechanics, Medicine, and Rehabilitation, SP, Brazil. 2. University of Missouri, Department of Orthopedics, Columbia, MI. Citation: Ferreira RAFH, Mascarenhas LB, Salim R, Ferreira AM, Fogagnolo F, Kfuri Junior M. Replacement versus non-replacement of the patellar joint surface in total knee arthroplasty. Acta Ortop Bras. [online]. 2018;26(3):175-8. Available from URL: http://www.scielo.br/aob. Work conducted at the Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, SP, Brazil. Correspondence: Rodrigo Salim. Departamento de Biomecânica, Medicina e Reabilitação do Aparelho Locomotor. Av. dos Bandeirante, Campus Universitário, S/N, Ribeirão Preto, São Paulo, Brazil. 14048-900. rodsalim@gmail.com Original article DOI: http://dx.doi.org/10.1590/1413-785220182603185026 All authors declare no potential confict of interest related to this article. Article received in 09/06/2017, approved in 12/18/2017. ABSTRACT Objective. This study addresses functional data, pain, and the reop- eration rate in patients undergoing primary total knee arthroplasty (TKA) during which the patella was or was not replaced. Methods: Fifty-three knees were included, 18 with the patella replaced and 35 with the patella not replaced. WOMAC and SF-12 scores and knee pain were analyzed preoperatively and 3, 6, and 12 months after TKA. The reoperation rate was also evaluated. Results: Both groups presented significant improvement in WOMAC score and pain at all postoperative follow-up appointments. There was no significant difference between the groups in all evaluated variables. Two subjects in the group did not undergo patellar replacement due to complaints of anterior knee pain after arthroplasty. There was no difference between the groups in relation to the reoperation rate. Conclusion: Patients receiving patellar replacement during TKA did exhibit significant differences in the rate of reoperation, function, or pain when compared to patients in which the patella was replaced. Level of Evidence III; Cohort study. Keywords: Arthroplasty. Knee. Patella. RESUMO Objetivo: Este estudo confronta dados funcionais, dor e taxa de re-operação de pacientes submetidos à ATJ primária, que substi- tuíram e que não substituíram a patela. Métodos: 53 joelhos, sendo 18 com a patela substituída e 35 com a patela não substituída. Womac, SF-12 e dor no joelho foram analisados no pré-operatório e após 3, 6 e 12 meses da ATJ. A taxa de re-operação também foi avaliada. Resultados: Ambos os grupos apresentam melhora significativa no questionário Womac e dor em todos os seguimentos pós-operatórios. Não houve diferença significativa entre os grupos em todas as variáveis avaliadas. Dois sujeitos no grupo NÃO foram submetidos a substituição da patela devido a queixas de dor an- terior no joelho após a artroplastia. Não houve diferença entre os grupos em relação a taxa de re-operação. Conclusão: Pacientes submetidos a substituição da patela na ATJ não obtiveram diferença significativa quanto a taxa de reoperação, função e dor quando comparados aqueles que não substituíram. Nível de evidência III; Estudo Coorte. Descritores: Artroplastia. Joelho. Patela. INTRODUCTION Disagreements on whether to replace or retain the patella during total knee arthroplasty (TKA) have been present throughout the history of knee surgery and continue, with no consensus in the current literature. Surgeons who prefer to replace the patella justify their decision by stating that this reduces the incidence of anterior knee pain, prevents future secondary revisions of the patella, provides greater patient satisfaction, improves overall function, and has a low rate of complications. Surgeons who opt not to substitute the patella indicate more physiological patellofemoral kinematics, the possibility of greater patellofemoral load support, conservation of the patellar bone, reduction of osteonecrosis of the patella, and prevention of complications associated with patellar replacement such as patella fractures, patellar ligament injury, wear or loosening of the implant, and instability. 1,2 Still others maintain that replacement should be selective and based on criteria such as age, quality of the patellar cartilage, the presence of crystal deposit disease, the positioning of the patella, and femoral component type. 3 Consequently, current studies comparing patients undergoing TKA with or without replacement of the patellar surface do not present a consensus regarding possible differences in the functional questionnaires, pain, or reoperation rate. Acta Ortop Bras. 2018;26(3):175-8