Samples of articular cartilage of femur, tibia and patella of 15 dogs with experimentally induced degenerative joint disease (DJD) were microscopically analyzed. Animals were distributed into three groups (n=5): the control group received no medication; the second group was treated with chondroitin sulfate and the third received sodium hyaluronate. Samples were processed and stained with HE and toluidine blue for morphological evaluation. The metabolic and proliferative activity of the chondrocytes was evaluated by the measurement of nucleolar organizer regions (NORs) after impregnation by silver nitrate. Significant differences were not observed (P>0.05) in the morphology among the groups, however, the group treated with sodium hyaluronate had a higher score suggesting a trend to a greater severity of the lesions. Significant differences were not observed (P>0.05) in the measurement of NORs, cells and NORs/cells among the groups. Although differences were not significant, sodium hyaluronate group showed higher NOR and cell counts which suggested an increase of the proliferation rate of chondrocytes. In addition, a higher NOR/cell ratio in the group treated with chondroitin sulfate suggested that this drug may have stimulated the metabolic activity of the chondrocytes, minimizing the lesions resulting from DJD.

Introdução/Objetivos: A osteocondrite dissecante é uma lesão que acomete o osso subcondral do joelho com efeitos secundários sobre a cartilagem articular. Não há consenso na literatura sobre as melhores opções de tratamento. Reportamos o caso de um paciente submetido a fixação com cavilhas ósseas corticais autólogas, por via aberta. Relato de Caso: Paciente de 16 anos de idade, sexo masculino, com queixa de dor e derrame articular no joelho esquerdo, exacerbados por atividades físicas, havia dez meses, com diagnóstico de osteocondrite dissecante em sua localização mais comum (face lateral do côndilo femoral medial). Paciente foi submetido a tratamento cirúrgico com redução do fragmento e fixação por via aberta, através de cavilhas ósseas corticais retiradas da região anteromedial da tíbia. Resultados: Paciente evoluiu bem, com cicatrização da lesão osteocondral, e boa função no pós-operatório. A fixação com parafusos metálicos permite compressão dos fragmentos, o que favorece a consolidação; entretanto, é necessário a retirada do material após oito semanas. Parafusos biodegradáveis não precisam ser retirados, mas podem evoluir com sinovite asséptica por reação de corpo estranho. A fixação com cavilhas ósseas corticais autólogas, que dispensa a utilização de material de síntese, tem resultados satisfatórios na literatura, e é uma técnica simples, não agressiva, que diminui os custos do procedimento, e que vem sendo menos utilizada nos últimos anos, em detrimento de técnicas mais moderna e mais caras. Conclusão: Este caso enfatiza a eficácia da fixação com cavilhas ósseas no tratamento da osteocondrite dissecante do joelho.Descritores: Joelho, Osteocondrite, Osteocondrite dissecante AbstractIntroduction/Purpose: Osteochondritis dissecans is a lesion that affects the subchondral bone of the knee with secondary effects on joint cartilage. A consensus is yet to be reached on literature about the best treatment option.  This case report consists of patient that underwent an open surgery with autologous cortical bone sticks fixation. Case report: 16-year-old patient, male, with pain and joint effusion on the left knee, that gets worse with physical activity, since ten months, with osteochondritis dissecans diagnosis located in the most usual place, in the lateral portion of the medial femoral condyle. Patient went through an open surgery that fixed the fragment with cortical bone sticks withdrawn from anteromedial portion of the tibia. Results: Patient resulted in full recovery, with healing of the osteochondral lesion and good post-operative function. The fixation with metal screws causes compression of the fragments, which is beneficial for the consolidation; however, it is necessary to remove the material after eight weeks. Biodegradable screws don’t need to be removed, but can progress with aseptic synovitis by foreign body reaction. Autologous cortical bone sticks fixation, which does not require the use of synthetic material, has satisfactory results in the literature, and it is a simple, non-aggressive technique that reduces the surgery costs. However, in the recent years, it has been less used in detriment of more modern and expensive techniques. Conclusion: This case report emphasizes the effectiveness of fixation with bone sticks on the treatment of osteochondritis dissecans of the knee.Key words: Knee, Osteochondritis, Osteochondritis dissecans