Functional investigation of bone implant viability using radiotracers in a new model of osteonecrosis

OBJECTIVES: Conventional imaging methods are excellent for the morphological characterization of the consequences of osteonecrosis; however, only specialized techniques have been considered useful for obtaining functional information. To explore the affinity of radiotracers for severely devascularized bone, a new mouse model of isolated femur implanted in a subcutaneous abdominal pocket was devised. To maintain animal mobility and longevity, the femur was harvested from syngeneic donors. Two technetium-99m-labeled tracers targeting angiogenesis and bone matrix were selected. METHODS: Medronic acid and a homodimer peptide conjugated with RGDfK were radiolabeled with technetium-99m, and biodistribution was evaluated in Swiss mice. The grafted and control femurs were evaluated after 15, 30 and 60 days, including computed tomography (CT) and histological analysis. RESULTS: Radiolabeling achieved high (>95%) radiochemical purity. The biodistribution confirmed good blood clearance 1 hour after administration. For 99mTc-hydrazinonicotinic acid (HYNIC)-E-[c(RGDfK)2, remarkable renal excretion was observed compared to 99mTc-methylene diphosphonate (MDP), but the latter, as expected, revealed higher bone uptake. The results obtained in the control femur were equal at all time points. In the implanted femur, 99mTc-HYNIC-E-[c(RGDfK)2 uptake was highest after 15 days, consistent with early angiogenesis. Regarding 99mTc-MDP in the implant, similar uptake was documented at all time points, consistent with sustained bone viability; however, the uptake was lower than that detected in the control femur, as confirmed by histology. CONCLUSIONS: 1) Graft viability was successfully diagnosed using radiotracers in severely ischemic bone at all time points. 2) Analogously, indirect information about angiogenesis could be gathered using 999mTc-HYNIC-E-[c(RGDfK)2. 3) These techniques appear promising and warrant further studies to determine their potential clinical applications.

Familial osteopetrosis in Agouti paca: report of nine cases / Osteopetrose familiar em Agouti paca: relato de nove casos

Nine cases of familial osteopetrosis were studied in Agouti paca rodents maintained in captivity. Animals were distributed in three groups depending on the severity of their skeletal lesions. Based upon clinical, radiological, and microscopic findings, it was concluded that one animal had level I lesions, three animals had level II lesions, and five animals had level III osteopetrosis and osteonecrosis. Throughout the entire axial and appendicular skeleton, there was an increased amount of both trabecular and cortical bone tissue. All analyzed bones showed thickened cortex and reduced medullary canals. Bone trabeculae were thick and confluent. Cortex showed a narrowing of Haversian canals. Numerous cementing lines resulted in typical mosaic patterns. Osteocytes were pycnotic. Osteonecrosis was characterized by the disappearance of osteocytes and bone matrix decomposition.

Descreveram-se nove casos de osteopetrose familiar em Agouti paca mantidas em cativeiro. Os animais foram distribuídos em três grupos de acordo com a gravidade das lesões do esqueleto. Com base nos exames clínico, radiológico e microscópico, foi concluído que um animal apresentou lesões de nível I, três animais tiveram lesões de nível II e cinco animais tiveram osteopetrose de nível III. Por todo o esqueleto axial e apendicular, a quantidade de osso trabecular e osteônico estava aumentada. Todos os ossos analisados mostraram córtex espesso e canais medulares reduzidos. As trabéculas ósseas eram espessas e confluentes. No córtex, verificou-se um estreitamento de canais de Havers. Numerosas linhas de cimentação resultaram em um padrão de mosaico típico. Osteócitos estavam picnóticos e a osteonecrose foi caracterizada pela morte dos osteócitos, com desintegração da matriz óssea.

Osteonecrose no adulto / Osteonecrosis in the adul

O presente artigo tem por objetivo fazer uma revisão de literatura recente e objetiva sobre a osteonecrose nos pacientes adultos, dando destaque a aspectos como epidemiologia, fisiopatologia, principais articulações acometidas e o devido tratamento.

Osteonecrosis en lupus eritematoso sistémico / Osteonecrosis in systemic lupus erythematosus

Osteonecrosis (ON) is a clinical entity characterized by aseptic necrosis of bone marrow and trabecular bone as a result of significant disruption of blood supply to the bone. In patients with systemic lupus erythematosus (SLE), ON is a well recognized complication, which also results in significant morbidity. The clinical course is usually progressive to end stage degenerative changes of the joints causing significant secondary pain and limitation of movement, and reducing the quality of life in these patients. Corticosteriod therapy is the major predisposing factor for ON in SLE. This article reviews the causes, clinical and epidemiological features, diagnosis and treatment options for ON among patients with SLE.

Osteonecrosis espontánea del platillo tibial medial post artroscopía. ¿Causa o efecto?: a propósito de un caso / Post arthroscopic spontaneous osteonecrosis of the medial tibial plateau. Cause or effect?: a case report

La osteonecrosis espontánea de la rodilla (ONE) es un cuadro muy poco frecuente que afecta de preferencia el cóndilo medial del fémur o el platillo tibial del mismo lado. Se presenta habitualmente en mujeres después de la quinta década de vida y con frecuencia está asociado o en concomitancia con procedimientos artróscopicos derivados de cuadros dolorosos de rodilla con algún grado de artrosis y lesiones meniscales. Las teorías más aceptadas que explican su etiología son dos: la primera se refiere a una insuficiencia vascular y la segunda a microtraumas repetidos. Se presenta el caso de una mujer de 86 años a quien se le practicó una artroscopía a raíz de un cuadro doloroso en su rodilla izquierda. Se le realizó una menicectomía parcial medial más sinovectomía. En su evolución posterior inmediata le fué diagnosticado una osteonecrosis extensa del platillo tibial medial lo que determinó que debiera ser sometida a una cirugía de reemplazo articular en la rodilla afectada. Se discute también el supuesto beneficio que tendría el realizar aseos y debridamientos artroscópicos en pacientes seniles con dolor de rodilla y artrosis, además de la oportunidad de un diagnóstico más acabado con RMI.

Aplicación clínica de la resonancia magnética en la rodilla: Parte II. Rodilla anormal / Clinical application of magnetic resonance imaging of the Knee: Part II. The abnormal knee

La imagen de la resonancia magnética es uno de los estudios con mayor exactitud y sensibilidad en el diagnóstico de patología de la rodilla, el conocimiento de las imágenes anormales más comunes permitirá una mejor interpretación que se reflejará en la correcta decisión en el tratamiento. Se describen las imágenes de la patología más frecuente en la rodilla, de las cuales debe de tener conocimiento el cirujano ortopedista

Osteonecrosis / Osteonecrosis

Son poco conocidos los trabajos investigativos, estadisticos o bibliograficos referentes a la necrosis osea avascular y su incidencia real de presentacion en nuestro medio. Por esta razon es muy frecuente encontrar el poco conocimiento y el manejo inadecuado de esta entidad, lo cual condujo a una exahustiva investigacion bibliografica con el fin de comprender en forma mas clara y concisa su etiopatogenia, presentacion clinica, clasificacion, diagnostico y tratamiento de acuerdo al estado de presentacion, con los articulos y publicaciones mas recientes. Posteriormente en una segunda fase del trabajo se revisan 14 pacientes del Hospital San Jose a quienes se practico trasplante renal, encontrando 2 pacientes que desarrollaron osteonecrosis: bilateral de caderas y en condilo femoral medial, clasificadas en Estato IV y III respectivamente a pesar de practicas biopsia diagnostica y terapeutica en el area comprometida. Se exponen las conclusiones correlacionando las 2 revisiones.

El manejo ortopédico de la osteonecrosis aséptica del transplantado renal / The management of aseptic osteonecrosis in patients with renal transplants

Se presenta el manejo ortopédico de 13 pacientes, quienes desarrollaron Osteonecrosis Aséptica después de haberse transplantado sus riñones. Esta Osteonecrosis es de evolución rápida y destructiva. Se considera el uso del Injerto Osteomuscular Pediculado como procedimiento para prevenir el colapso óseo, en fase inicial, pero es la Artroplastia Total el método definitivo para lograr alivio. El acto quirúrgico impone una serie de precauciones pre, trans y post-operatorias