OBJECTIVES: The aim of this study was to evaluate the role of amphiregulin protein, an epidermal growth factor receptor ligand, in cartilaginous tumors. METHODS: Amphiregulin expression was examined in 31 enchondromas and 67 chondrosarcomas using immunohistochemistry analysis. RESULTS: Overall, 15 enchondromas (48.40%) and 24 chondrosarcomas (35.82%) were positive for amphiregulin. According to the receiver operating characteristic curve test, no difference in amphiregulin expression was observed between enchondromas and low-grade chondrosarcomas (p=0.0880). Additionally, 39 lesions (16 in short bones, 13 in long bones, and 10 in flat bones) were positive for amphiregulin, exhibiting a higher percentage of positive cells (p=0.0030) and intensity of immunohistochemical expression (p=0.0055) in short bone lesions than in others. Among 25 enchondromas localized in short bones, 15 expressed amphiregulin; however, all 6 cases localized in long bones were negative for this marker (p=0.0177). CONCLUSIONS: Amphiregulin did not help in distinguishing enchondromas from low-grade chondrosarcomas. The present study is the first to document the expression of this immunohistochemical marker in enchondromas. Furthermore, amphiregulin expression in enchondromas was localized in short bones, indicating a phenotypic distinction from that in long bones. This distinction may contribute to an improved understanding of the pathogenesis of these lesions.

OBJETIVO: Comparar os resultados clínicos, radiográficos e de seguimento a médio prazo de dois métodos de fixação do componente tibial nas cirurgias de revisão de prótese total do joelho: cimentada (bandeja e haste) e híbrida (bandeja cimentada e haste que preenche o canal não cimentada e não porosa). MÉTODOS: Entre agosto de 1999 e novembro de 2005, 30 cirurgias de revisão de artroplastia total do joelho foram realizadas em 26 pacientes, sendo divididas em: grupo I: fixação cimentada (N = 21); grupo II: híbrida (N = 9). O tempo médio de acompanhamento foi de 52 meses, e não houve perda de seguimento pós-operatório. RESULTADOS: Não foram observadas diferenças nos resultados dos valores dos questionários da Womac e do Knee Society Score entre os dois grupos. Um paciente do grupo I apresentou sinais radiográficos de soltura. Dois pacientes (um de cada grupo) referiram dor na região diafisária, compatível com o local da ponta das hastes. O sinal radiográfico de "pedestal" esteve presente em 89% dos joelhos com hastes não cimentadas e em nenhum com haste cimentada. CONCLUSÃO: A análise comparativa entre os dois métodos não mostrou diferenças nos parâmetros clínico, radiográfico e de sobrevida da artroplastia.

OBJECTIVE: To compare the clinical, radiographic and medium-term follow-up results from two fixation methods for the tibial component in revision procedures on total knee prostheses: cemented (tray and stem) and hybrid (cemented tray and uncemented, nonporous canal-filling stem). METHODS: Between August 1999 and November 2005, 30 revision procedures on total knee arthroplasties were performed on 26 patients, who were divided between group I (cemented fixation; 21 knees) and group II (hybrid fixation; nine knees). The mean follow-up was 52 months and no patients were lost from the follow-up. RESULTS: No differences in the scores from the WOMAC and Knee Society questionnaires were observed between the two groups. One patient in group I presented radiographic signs of loosening. Two patients (one in each group) complained of pain in the diaphyseal region, compatible with the location of the stem tip. The pedestal radiographic sign was observed in 89% of the knees with uncemented stems and in none of the cemented group. CONCLUSION: The comparative analysis between the two methods did not show any differences regarding clinical and radiographic parameters, or arthroplasty survival.

OBJECTIVES: To study the role of angiogenesis and cyclooxygenase-2 expression in cartilaginous tumors and correlate these factors with prognosis. INTRODUCTION: For chondrosarcoma, the histological grade is the current standard for predicting tumor outcome. However, a low-grade chondrosarcoma can follow an aggressive course-as monitored by sequential imaging techniques-even when it is histologically indistinguishable from an enchondroma. Therefore, additional tools are needed to help identify the biological potential of these tumors. The degree of angiogenesis that is induced by the tumor could assist in this task. Angiogenesis can be quantified by measuring the expression of vascular endothelial growth factor and CD34, and cyclooxygenase-2 can induce angiogenesis by stimulating the production of proangiogenic factors. METHODS: In total, 21 enchondromas and 58 conventional chondrosarcomas were studied by examining the clinical and histopathological findings in conjunction with the immunostaining markers of angiogenesis and cyclooxygenase- 2 expression. RESULTS: The significant variables that were associated with poor outcome were 1) higher-grade chondrosarcomas, 2) tumors that developed in flat bones, and 3) over-expression of CD34 (with a median count that was higher than 5.9 vessels in 5 high power fields). Moreover, CD34 expression (measured using the Chalkley method) revealed significantly higher microvessel density in flat bone chondrosarcomas. DISCUSSION: Previous studies have shown a positive correlation between Chalkley microvessel density and histological grade; however, in our sample, we found that the former is predictive of the outcome. Chondrosarcomas in flat bones have been shown to correlate with a poor prognosis. We also found that CD34 microvessel density values were significantly higher in flat-bone chondrosarcomas. This could explain-at least in part-the more aggressive biological course that is taken by these tumors. CONCLUSIONS: These results provide evidence that CD34 microvessel density in chondrosarcomas can be helpful in predicting patient outcome and may add to our understanding of chondrosarcoma pathogenesis.