ObjectiveSeveral studies show that patients undergoing total knee arthroplasty (TKA) tend to maintain or gain weight after the procedure, which would result in increased wear of the prosthesis and new surgical interventions in a smaller period of time in comparison with patients with adequate body mass index (BMI). The aim of this study was to investigate the effect of TKA surgery on these patients’ BMI.MethodsInitially the records were analyzed, chosen at random from 91 patients undergoing TKA during the period from August 2011 to July 2013. Patients were stratified by BMI as normal weight (BMI between 20 and 25), overweight (BMI between 25 and 30), and obesity (BMI > 30). They were re-evaluated in a minimum period of 18 months.ResultsThe mean age of the sample population was 68.1 years; 69.1 for men and 67.2 for women. The mean preoperative BMI was 27.24 kg/m2. Among the study participants, in the preoperative period, 17 patients had normal weight, 65 were overweight, and nine were obese. Postoperative analysis showed weight loss in 41 patients (46%), and weight gain in 50 patients (54%). The mean postoperative BMI was 27.16 kg/m2, in general, experiencing a slight decline in the mean BMI of 0.08 kg/m2.ConclusionPatients who underwent TKA did not achieve significant reduction in BMI after surgery.

Dislocation of the polyethylene component in knee arthroplasty is a rare complication. The main triggering factor is failure of the locking mechanism, which may result from technical errors of insertion, trauma or even implant failure. Here, a case of dislocation of the polyethylene component from the tibial base, nine years after revision arthroplasty, is reported. It is believed that this is the first such case reported in the Brazilian literature.

Resumo Objetivo Demonstrar a maior acurácia das radiografias panorâmicas de membros inferiores (longas) em relação às radiografias curtas do joelho na medida do eixo mecânico do membro inferior após a artroplastia total de joelho (ATJ). Métodos Foi realizado um estudo retrospectivo para avaliar a acurácia de imagens radiográficas longas e curtas pós-operatórias de 70 pacientes submetidos à ATJ em nosso serviço. As imagens foram analisadas ao acaso, em momentos distintos, por três ortopedistas. Em todas as imagens, o eixo mecânico do membro, do fêmur e da tíbia foram traçado,s e os ângulos femorotibiais (AFTs) foram calculados. O coeficiente de correlação intraclasse (CCI) foi calculado para avaliar a concordância da medida do eixo mecânico inter e intraobservador. Resultados Observou-se que houve alta concordância intra e interobservador quando utilizamos radiografias panorâmicas, apresentando CCI mínimo intrae interobservador de 0,89, equivalente a uma concordância fortíssima. Já nas radiografias curtas na incidência anteroposterior (AP) do joelho, o CCI mostrou-se com concordância moderada, obtendo valor máximo de 0,75. Conclusão Existe uma diferença significativa na acurácia para a medida do eixo mecânico do membro inferior, comparando-se radiografias longas e curtas do membro inferior. Assim, para a adequada mensuração do eixo mecânico do membro inferior, sugerimos a realização de radiografia longa no pós-operatório de ATJ.

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Instability MPFL reconstruction Failure a b s t r a c tPurpose: To ascertain whether differences exist in joint instability after experimentally induced failure of medial patellofemoral ligament (MPFL) reconstruction in the cadaver knee with the four graft types most widely used for this procedure, and whether any of these grafts are associated with decreased risk in the event of failure.Methods: Between March 2011 and March 2012, eight cadavers obtained from the local medical examiner's office were randomly allocated into four groups (four knees each). In each group, a different graft technique was used for MPFL reconstruction. The forces required to induce lateral dislocation of the patella before reconstruction and after experimental failure of surgical reconstruction were recorded. The tested graft techniques were then compared to assess which was associated with the least instability after failed reconstruction.Results: When we compared the groups I (semitendinosus) and II (patellar tendon), the mean differences of the force required to produce a dislocation of the patella before and after the failure were 0.5 N and 12.5 N, respectively (p ¼ 0.028). In comparison between groups I and III (medial third of the quadriceps tendon) the mean differences of the force required to produce dislocation before and after the failure caused were 0.5 N and 22 N, respectively (p < 0.001). In comparison between groups I and IV (Medial third of the quadriceps tendon) we found the mean differences of the force required to produce dislocation before and after the failure caused were 0.5 N and 5 N, respectively (p > 0.999).Conclusions: There were differences in residual instability after simulated MPFL reconstruction failure depending on graft type. Use of the free semitendinosus graft technique was associated with the least risk of residual instability in case of reconstruction failure.