Polietileno tibial móvel na artroplastia total do joelho Mobile polyethylene bearing in total knee replacement

O desgaste do polietileno tibial utilizado nas artroplastias de joelho origina partículas que, quando fagocitadas, dão início à cascata de eventos biológicos que levam à osteólise e consequente afrouxamento dos componentes da prótese. Assim sendo, alternativas para o polietileno têm sido pesquisadas com o objetivo de minimizar o desgaste e, com isso, aumentar a durabilidade das artroplastias. Uma dessas opções é a utilização de polietilenos tibiais móveis, que apresentam maior conformidade do que os polietilenos fixos, ao mesmo tempo em que permitem autoalinhamento rotacional entre os componentes, melhorando, dessa forma, a cinética e a cinemática da prótese. São apresentados aqui, de forma resumida, porém abrangente, o conceito, os fundamentos biomecânicos, as indicações, os resultados esperados e complicações dos polietilenos tibiais móveis nas artroplastias totais do joelho.<br>Debris of polyethylene tibial bearings have been recognized as a major cause for the onset of the cascade of biological events leading to osteolysis and loosening of prosthetic components after total knee arthroplasty. Since then, research has been focused on alternative bearing surfaces in order to minimize the amount and rate of polyethylene wear off and, in doing so, increasing the survivorship rate for knee arthroplasties. One such option is to have a mobile tibial bearing allowing more conformity and rotational self-alignment of the components, improving kinetics and kinematics of the prosthesis. The authors present a resumed but throughout and comprehensive review of the rationale, biomechanics fundamentals, indications, pitfalls, outcomes and complications for the use of mobile tibial bearings in total knee replacement

Avulsion fracture of the posterior cruciate ligament in an uncommon location associated with distal injury to the patellar ligament

ABSTRACT Avulsion fractures of the posterior cruciate ligament in unusual locations are rare injuries. We report the first case in the literature of an avulsion fracture of the posterior cruciate ligament associated with distal injury to the patellar ligament. The aim of this study was to present a novel case, the therapy used and the clinical follow-up

Anthropometric study of the knee and its correlation with the size of three implants available for arthroplasty

ABSTRACT OBJECTIVE: To define the anthropometric profile of the knee in a Brazilian population with gonarthrosis using intraoperative measurements; and to evaluate the compatibility of three implants available for total knee arthroplasty. METHODS: Morphometric data were collected prospectively from 117 subjects with gonarthrosis. Six dimensions in the distal femur and two in the proximal tibia were documented in 118 knees while performing total arthroplasty. These data were compared with the dimensions of three implants available for total knee arthroplasty. RESULTS: The statistical analysis showed that more than a quarter of the patients presented an unsatisfactory relationship between the knee and prosthesis. CONCLUSION: The implants evaluated need to be adjusted to better fit Brazilian patients

Amputation after failure or complication of total knee arthroplasty: prevalence, etiology and functional outcomes

OBJECTIVE: Identify the etiology and incidence, as well to assess functional outcomes of patients, undergoing lower limb amputation after failure or complication of total knee arthroplasty. These patients were treated at the Center for Knee Surgery at the National Institute of Traumatology and Orthopedics (INTO), during the period of January 2001 to December 2010. METHODS: The patients were interviewed and their charts were retrospectively analyzed to evaluate their functional outcome. RESULTS: The incidence of amputation due to failure or complication of total knee arthroplasty was 0.41% in 2409 cases. Recurrent deep infection was the cause of amputation in 81% of cases, being Staphylococcus aureus and Pseudomonas aeruginosa the most frequent germs. Vascular complications and periprosthetic fracture associated to metaphyseal bone loss were also causes of amputation. In our study, 44% of amputees patients were using orthesis and 62.5% have had the ability to walk. CONCLUSION: Incidence of 0.41%, being the main cause recurrent infection. The functional outcome is limited, and the fitting achieved in 44% of patients and only 62.5% are ambulatory

Magnetic resonance study on the anatomical relationship between the posterior proximal region of the tibia and the popliteal artery ☆

ABSTRACTOBJECTIVE: To analyze and describe the distance from the popliteal artery to three specific areas of the proximal region of the tibia, with the knee extended, by means of magnetic resonance. METHODS: Images of 100 knees of patients who underwent magnetic resonance examinations were analyzed. The location of the popliteal artery was measured in three different areas of the posterior proximal region of the tibia. The first measurement was made at the level of the knee joint (tibial plateau). The second was 9 mm distally to the tibial plateau. The third was at the level of the anterior tuberosity of the tibia (ATT). RESULTS: The distances between the popliteal artery and the tibial plateau and ATT region were significantly greater in males than in females. The distances between the popliteal artery and the regions 9 mm distally to the tibial plateau and the ATT were significantly greater in the age group over 36 years than in the group ≤36 years. CONCLUSION: Knowledge of the anatomical position of the popliteal artery, as demonstrated through magnetic resonance studies, is of great relevance in planning surgical procedures that involve the knee joint. In this manner, devastating iatrogenic injuries can be avoided, particularly in regions that are proximal to the tibial plateau and in young patients

Estudo prospectivo randomizado após uso de dreno na artroplastia total do joelho com implante

OBJECTIVE:to compare the laboratorial results of opening suction drainage 6 hours and 12 hours after total knee arthroplasty surgery.METHODS:prospective and randomized study in 88 patients undergoing with total knee arthroplasty in two groups: in one group the opening suction drainage was performed 6 hours (n = 45) after the surgery and in the other 12 hours (n = 43) after the surgery.RESULTS : the outcome was a significant fall in the three laboratorial variables (hemoglobin, red blood cells and hematocrit) between the pre and post-operative in the total sample and in the six and 12 hour opening suction drainage groups. In the group with opening suction drainage after 12 hours, the drainage volume was significantly lower than in the group with opening suction drainage after 6 hours (p = 0.0003). However, no significant difference was observed in the absolute delta of the laboratorial variables between the two groups.CONCLUSION:the opening suction drainage in six and 12 hours did not show significant difference from the laboratorial values although the volume of the blood drained was higher in the opening suction drainage in six hours.OBJETIVO : Comparar os resultados laboratoriais da abertura do dreno seis e 12 horas após a cirurgia de artroplastia total do joelho. MÉTODOS : Estudo prospectivo e randomizado em 88 pacientes tratados com artroplastia total do joelho com implante em dois grupos: um com abertura do dreno seis horas (n = 45) após a cirurgia e outro, 12 horas (n = 43) após a cirurgia.RESULTADOS : Existe uma queda significativa nas três variáveis laboratoriais (hemoglobina, hemácias e hematócrito) entre o pré e o pósoperatório na amostra total e nos grupos de tempo de abertura do dreno às seis e 12 horas. O grupo com tempo de abertura após 12 horas apresentou volume do dreno significativamente menor do que o grupo com tempo de abertura após 6 horas (p = 0,0003). Contudo, não foi verificada diferença significativa no delta absoluto das variáveis laboratoriais entre os dois grupos. CONCLUSÃO : A abertura do dreno em seis e 12 horas não demonstrou diferença significativa dos valores laboratoriais. Porém, o volume de sangue drenado foi maior com abertura do dreno após seis horas.Hospital Santa Teresa Clinical Head and Physician in charge of the Knee Group of Prof. Dr. Donato D'Ângelo Orthopedics and Traumatology ServiceHospital Santa TeresaInstituto Nacional de Traumato-OrtopediaINTOUniversidade Federal de São Paulo (UNIFESP) Escola Paulista de MedicinaUNIFESP, EPMSciEL