1/5. Metachondromatosis and avascular necrosis of the femoral head: a radiographic and histologic correlation.We report the case histories, radiographic and computed tomographic studies, and histologic findings of two children with metachondromatosis who developed avascular necrosis (AVN) of the femoral ossific nucleus. The first was a 9-year-old boy with involvement of both femoral heads; the second was an 8-year-old girl with involvement of her right femoral head. The changes were associated with either exostoses or enchondromalike lesions of the femoral neck. Interference with the integrity of the lateral epiphyseal vessels by these lesions would explain the avascular changes that occurred. The findings in these cases and other reports associating AVN with skeletal dysplasia should encourage treating physicians to analyze carefully a sudden increase in hip pain or rapid radiographic development of femoral head collapse in a child with a skeletal dysplasia. Recognition of true AVN, in contrast to the gradual evolution of head shape change in typical skeletal dysplasia, may change treatment recommendations and prognosis.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
2/5. legg-calve-perthes disease. Histochemical and ultrastructural observations of the epiphyseal cartilage and physis.biopsy specimens of the lateral aspect of the femoral head and neck were obtained from five children with legg-calve-perthes disease and were studied using histochemistry and electron microscopy. Beneath the normal articular cartilage there was a thick zone of hyaline (epiphyseal) cartilage containing sharply demarcated areas of hypercellular and fibrillated cartilage with prominent blood vessels. The fibrillated cartilage was strongly positive to alcian blue, weakly positive to periodic acid-Schiff, and positive to aniline blue. The interterritorial matrix in the hypercellular areas was weakly positive to both alcian blue and periodic acid-Schiff. Ultrastructural examination of these areas revealed many irregularly oriented large collagen fibrils and variable amounts of proteoglycan granules. These results suggest that in the fibrillar areas there are: (1) a high proteoglycan content, (2) a decrease in structural glycoproteins, and (3) a different size of collagen fibrils from that of normal epiphyseal cartilage. The hypercellular areas had a decrease in proteoglycans, glycoproteins, and collagen. The lateral physeal margin was often irregular, with a marked reduction of collagen and proteoglycan granules, and contained numerous large lipid inclusions. CLINICAL RELEVANCE: The abnormal areas in the epiphyseal cartilage of patients with legg-calve-perthes disease have different histochemical and structural properties from normal cartilage and from fibrocartilage. This suggests that the disease could be a localized expression of a generalized, transient disorder of epiphyseal cartilage that is responsible for delayed skeletal maturation. The cartilage lesions are similar to those seen in the vertebral plates in patients with juvenile kyphosis. Whether the epiphyseal cartilage abnormalities are primary or are secondary to ischemia remains uncertain; however, it appears that the collapse and necrosis of the femoral head could result from the breakdown and disorganization of the matrix of the epiphyseal cartilage, followed by abnormal ossification.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
3/5. Case report: avascular necrosis of the femoral head as a complication of complex embolization for severe pelvic haemorrhage.We present a case of avascular necrosis of the femoral head following embolization of the right medial femoral circumflex artery with alcohol after a failed prior internal iliac artery ligation to control benign pelvic haemorrhage in a 41-year-old woman. No case of late necrosis of the head of the femur as a complication of iliac artery vessel embolization to control haemorrhage has been documented previously. The problems associated with therapeutic pelvic embolization following ligation of the internal iliac artery and the disruption of the femoral head arterial supply are discussed.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
4/5. Avascular necrosis of the femoral head following cardiac transplantation: report of a case.Avascular necrosis of the femoral head occurred following cardiac transplantation in a 28-year-old man. After cardiac surgery the patient was treated with prednisone and experienced 2 "rejection" episodes. hip pain began 5 months postoperatively. Roentgenograms revealed rapidly progressive avascular necrosis in both hips. The sequence of events leading to avascular necrosis of bone in this patient is identical to that following other organ transplantations and includes steroid-induced hyperlipemia, fatty infiltration of the liver, systemic fat emboli to subchondral vessels and avascular necrosis.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |
5/5. Fat embolism, intravascular coagulation, and osteonecrosis.A triad of intraosseous fat embolism, intravascular coagulation (both thrombosis and hemorrhage), and osteonecrosis was pathologically demonstrated to coexist for the first time in humans. Specimens were evaluated from the earliest nontraumatic (18 hours) and traumatic (29 hours) femoral head lesions yet reported, and the cause and early pathogenesis were confirmed in a third case. An absolute overload of subchondral fat emboli, with hypercoagulability, stasis, and endothelial damage by free fatty acids, appears to cause end-organ death by triggering intravascular coagulation. This intermediary pathway appears to be capable of producing osteonecrosis by progressive fibrin platelet thromboses, which begin in vulnerable subchondral capillaries and sinusoids, especially when associated with arteriolar vasoconstriction and impaired secondary fibrinolysis (reperfusion of necrotic vessels with peripheral marrow hemorrhages). A relative overload of subperiosteal and subchondral fat emboli, which is below the ischemic/anoxic threshold but insufficient for intravascular coagulation, may cause osteopenia.- - - - - - - - - - ranking = 1keywords = vessel (Clic here for more details about this article) |