RESUMO
ABSTRACT Objective: To evaluate the results of total knee arthoplasty revisions performed in high complexity cases, with large bone defects or serious ligament deficiencies using a constrained implant hinge associated to a rotating tibial basis. Methods: We evaluated 11 patients in which we used the constrained implant hinge associated to rotating tibial basis, with minimum follow-up of two years. The indications for the procedure included instability, septic loosening, late postoperative infection without loosening and periprosthetic fracture. We evaluated the knee range of movement and functional outcomes by the Knee Society Score (KSS) e Knee Injury and Osteoarthritis Outcome Score (KOOS), besides the presence of complications. Results: All patients achieved 5o to 85o minimum range of motion at 1 year postoperatively and, in the present evaluation, KSS ranged from 67 to 95. Three patients had no complications until the last evaluation and two patients required implant revision. Conclusion: Despite the complications rate observed, the functional result were acceptable for most patients, and it proved being a viable alternative, especially for patients with low functional demand. Level of Evidence IV, Case Series.
RESUMO
Um dos avanços tecnológicos mais significativos da medicina atual é a cirurgia assistida por computador, sendo que na ortopedia uma das aplicações mais importantes dessa tecnologia é na artroplastia do joelho. A principal contribuição da cirurgia ortopédica assistida por computador (Computer Aided Orthopaedic SurgeryÆs - CAOS) na artroplastia do joelho é o seu potencial em aprimorar a precisão da implantação das próteses e do alinhamento do membro operado contribuindo para a otimização e longevidade dos resultados. A navegação independente de imagens, baseada em referências anatômicas adquiridas durante o ato cirúrgico através de transmissores de raios infra-vermelho, tem sido a técnica preponderante na artroplastia do joelho. Utilizamos o sistema de navegação para artroplastia total do joelho "OrthoPilot" versão 2.2 para a colocação de 72 próteses de joelho "Search Evolution" da "Aesculap AG CO. KG" com ou sem estabilização posterior em uma série contínua. O objetivo foi aferir a precisão do alinhamento obtido com a navegação através de radiografias panorâmicas obtidas no período pós-operatório. Obtivemos um desvio médio do eixo mecânico nulo de 0,66° com desvio padrão de 0,7°, sendo que 98,6 por cento dos joelhos ficaram dentro de uma margem de erro de 3° e 79,2 por cento com erro inferior a 1°. Concluímos que o sistema é seguro e preciso, não adicionando morbidade à cirurgia convencional.
One of the most significant technological advancements in current medicine is the computer-assisted surgery, which, for orthopaedics, one of the major uses of this technology is in knee arthroplasty. The main contribution provided by computer-assisted orthopaedic surgery (CAOS) to knee arthroplasty is its potential to improve prosthesis implant precision and the operated limb alignment, contributing to results optimization and longevity. The image-independent navigation, based on anatomical references acquired during surgical procedure through infrared raysÆ transmitters, has been the prevailing technique in knee arthroplasty. We used the navigation system "OrthoPilot" version 2.2 in total knee arthroplasty for inserting 72 knee prosthesis "Search Evolution" by "Aesculap" with or without posterior stabilization in a continuous series. The objective was to measure the accuracy of the alignment achieved with navigation through wide-angled X-ray images obtained postoperatively. We found a mean deviation for the null mechanical axis of 0.66° with standard deviation of 0.7°, with 98.6 percent of the knees being within an error margin of 3° and 78.2 percent with error lower than 1°. We concluded that the system is safe and accurate, not causing additional morbidity to conventional surgery.