Alignment of the tibial component in total knee arthroplasty procedures using an intramedullary or extramedullary guide: double-blind randomized prospective study.

OBJECTIVES: To evaluate the results obtained through using an intramedullary or extramedullary guide for sectioning the tibia in total knee arthroplasty procedures, with a view to identifying the accuracy of these guides and whether one might be superior to the other. METHODS: This was a randomized double-blind prospective study on 41 total knee arthroplasty procedures performed between August 2011 and March 2012. The angle between the base of the tibial component and the mechanical axis of the tibia was measured during the immediate postoperative period by means of radiography in anteroposterior view on the tibia that encompassed the knee and ankle. RESULTS: There was no demographic difference between the two groups evaluated. The mean alignment of the tibial component in the patients of group A (intramedullary) was 90.3° (range: 84-97°). In group B (extramedullary), it was 88.5° (range: 83-94°). CONCLUSION: In our study, we did not find any difference regarding the precision or accuracy of either of the guides. Some patients present an absolute or relative contraindication against using one or other of the guides. However, for the other cases, neither of the guides was superior to the other one.

OBJETIVOS: Avaliar os resultados obtidos com o uso de guia intramedular ou extramedular para o corte tibial em artroplastias totais do joelho, com vistas a identificar sua acurácia e a superioridade de um em relação ao outro. MÉTODOS: Estudo prospectivo, randomizado, duplo cego de 41 artroplastias totais de joelho feitas entre agosto de 2011 e março de 2012. Foi medido o ângulo entre a base do componente tibial e o eixo mecânico da tíbia no período pós-operatório imediato por meio de radiografia em incidência anteroposterior da tíbia que englobou joelho e tornozelo. RESULTADOS: Não houve diferença demográfica entre os dois grupos avaliados. O alinhamento médio do componente tibial nos pacientes do grupo A (intramedular) foi de 90,3° (84°-97°). No grupo B (extramedular), foi de 88,5° (83°-94°). CONCLUSÃO: Não encontramos, em nosso estudo, diferença quanto à precisão ou acurácia de qualquer um dos guias. Alguns pacientes apresentam contraindicação, absoluta ou relativa, para o uso de um ou outro guia. Todavia, para os demais casos, não há superioridade de algum deles.

Characterization of hip and knee arthroplasties and factors associated with infection.

OBJECTIVE: To characterize arthroplasty procedures, calculate the surgical infection rate and identify related risk factors. METHODS: This was a retrospective cohort study. Data on operations performed between 2010 and 2012 were gathered from documental sources and were analyzed with the aid of statistical software, using Fisher's exact test, Student's t test and the nonparametric Mann-Whitney and Wilcoxon tests. RESULTS: 421 total arthroplasty procedures performed on 346 patients were analyzed, of which 208 were on the knee and 213 on the hip. It was found that 18 patients (4.3%) were infected. Among these, 15 (83.33%) were reoperated and 2 (15.74%) died. The prevalence of infection in primary total hip arthroplasty procedures was 3%; in primary total knee arthroplasty, 6.14%; and in revision of total knee arthroplasty, 3.45%. Staphylococcus aureus was prevalent. The length of the surgical procedure showed a tendency toward being a risk factor (p = 0.067). CONCLUSION: The prevalence of infection in cases of primary total knee arthroplasty was greater than in other cases. No statistically significant risk factors for infection were identified.

OBJETIVO: Caracterizar as artroplastias, calcular a taxa de infecção cirúrgica e identificar fatores de risco relacionados. MÉTODOS: Estudo de coorte retrospectivo. Os dados das cirurgias feitas entre 2010 e 2012 foram coletados em fontes documentais e analisados com auxílio de programa estatístico e testes exato de Fisher, t de Student e não paramétrico de Mann­Whitney e Wilcoxon. RESULTADOS: Foram analisadas 421 artroplastias totais em 346 pacientes, 208 de joelho e 213 de quadril; 18 (4,3%) pacientes infectaram; entre esses, 15(83,33%) foram reoperados e dois (15,74%) evoluíram para óbito. A prevalência de infecção em artroplastia total de quadril primária foi de 3%, em artroplastia total de joelho primária de 6,14% e em revisão de artroplastia total de joelho de 3,45%; Staphylococcus aureus foi prevalente. O tempo de duração da cirurgia indicou uma tendência como fator de risco (p = 0,067). CONCLUSÃO: A prevalência de infecção em artroplastia total de joelho primária foi superior às demais e não foram identificados fatores de risco para infecção com significância estatística.

PERIPROSTHETIC FRACTURES IN TOTAL KNEE ARTHROPLASTY.

The increasing number of total knee arthroplasties, in combination with the population's longer life expectancy, has led to a greater number of long-term complications. These add to the poor bone quality of elderly patients and often culminate in periprosthetic fractures. This complex orthopedic problem has a great diversity of clinical presentation. It may affect any of the bones in the knee and, because of the difficulty in finding solutions, may lead to disastrous outcomes. Its treatment requires that orthopedists should have broad knowledge both of arthroplasty techniques and of osteosynthesis, as well as an elaborate therapeutic arsenal including, for example, access to a bone bank.

REVISION TOTAL HIP ARTHROPLASTY USING A MODULAR CEMENTLESS DISTAL FIXATION PROSTHESIS: THE ZMR(®) HIP SYSTEM. CLINICAL AND RADIOGRAPHIC ANALYSIS OF 30 CASES.

OBJECTIVE: To evaluate the clinical and radiographic results from 30 cases of revision of total hip arthroplasty using a modular cementless distal fixation prosthesis: the ZMR(®) Hip System. METHOD: Between July 2005 and December 2008, 30 operations were performed, on 14 men and 14 women. Two male patients had bilateral surgery. The mean age was 59.2 years (29-81 years), with a mean follow-up of 24 months. The Paprosky classification was used for periprosthetic bone loss, and the Harris Hip Score (HHS) was used to evaluate clinical results. On radiographs, distal migration of the femoral stem was defined in accordance with Sporer. Proximal bone remodeling was classified using the Callaghan criteria. RESULTS: The mean preoperative HHS was 39, and there was a significant increase to 93 points in the final evaluation, which indicated excellent clinical results. No femoral stem migration greater than 5 mm (Sporer) was observed on radiographs, thus suggesting that all the femoral prostheses presented osseointegration and remained stable from the time of the surgery until the final evaluation. The proximal femoral remodeling was either type B or type C in 29 hips, according to Callaghan. Seven patients had complications, but without interfering with osseointegration of the femoral components. CONCLUSION: Our results from revision of total hip arthroplasty using the ZMR(®) Hip System were extremely encouraging, and all the components became osseointegrated and remained fixed at the time of the final evaluation.

BONE BANKS.

Bone banks are necessary for providing biological material for a series of orthopedic procedures. The growing need for musculoskeletal tissues for transplantation has been due to the development of new surgical techniques, and this has led to a situation in which a variety of hospital services have been willing to have their own source of tissue for transplantation. To increase the safety of transplanted tissues, standards for bone bank operation have been imposed by the government, which has limited the number of authorized institutions. The good performance in a bone bank depends on strict control over all stages, including: formation of well-trained harvesting teams; donor selection; conducting various tests on the tissues obtained; and strict control over the processing techniques used. Combination of these factors enables greater scope of use and numbers of recipient patients, while the incidence of tissue contamination becomes statistically insignificant, and there is traceability between donors and recipients. This paper describes technical considerations relating to how a bone bank functions, the use of grafts and orthopedic applications, the ethical issues and the main obstacles encountered.

Computerized photocolorimetric analysis of the effects of intraarticular betamethasone on the proteoglycan concentration of leporine knee cartilage matrix: influence of the number of intraarticular injections.

OBJECTIVE: To study the effects of repeated injections of betamethasone on proteoglycan concentration in the articular cartilage of normal knees of Californian rabbits of both sexes. METHODS: Eighty animals were randomly divided into eight groups of ten animals each. Three control groups (saline solution injected or not) and five study groups - therapeutical doses, repeated or not, of betamethasone injected into the right knee of each animal at weekly intervals. After eight days from the last injection, sections of articular cartilage from tibial plateaus collected from weight-bearing surfaces were stained with hematoxylin and eosin for light microscopy analysis and with safranin O for the proteoglycan content assay. The staining intensity of safranin O was quantified by histomorphometry using an Olympus BX 50 microscope and a microcomputer with the Image Pro-plus 4.5O software. RESULTS: Animals receiving one, two and four betamethasone injections showed no differences when compared to normal controls. Animals receiving six and eight injections had a significant decrease in safranin O staining intensity (p < 0.05) as compared to the control groups and the other study groups. CONCLUSION: A decrease in the concentration of articular cartilage proteoglycans dependent on repeated betamethasone injection was effectively demonstrated.