Histological appearance of the intra-osseous vessels of the femoral head in aseptic osteonecrosis of the hip, with or without antiphospholipid antibodies.

UNLABELLED: It has been suggested that in some patients non-traumatic aseptic osteonecrosis of the hip (AOH) could be the result of the intra-osseous thrombosis. Antiphospholipid antibodies (APL) have been associated with venous and arterial occlusive events and the association between AOH and APL syndrome has been reported. OBJECTIVES: To compare bone vessels of the femoral head in patients operated on for AOH with or without APL. PATIENTS: Twenty patients (mean age 47 yrs) with AOH were included: in eight patients APL (IgG-ELISA) were negative (< 8 GPL units), in nine patients APL were doubtful (8-15 GPL units), and in three patients APL were positive (> 15 GPL units). METHODS: Bone vessels were examined: arteriosclerotic lesions, i.e. fibrosis or thickening of the media and rupture of the internal elastic lamina, thrombosis or vasculitis were sought in the femoral heads after total hip replacement or core decompression. RESULTS: Bone vessel lesions were the same in the three groups.

Effect of ovariectomy on intraosseous vascularization and bone remodelling in rats: action of tiludronate.

In order to study the action of tiludronate on the changes in intraosseous vascularization induced by ovariectomy, and to link these effects to those observed in bone remodelling, 30 female Sprague-Dawley rats (age 40 weeks) were studied. Ten rats were shamoperated and treated by vehicle, 10 rats were ovariectomized and treated by vehicle, and 10 rats were ovariectomized and treated orally with tiludronate, 0.16 mmol/kg/per day, 3 days a week for 16 weeks, from the day following ovariectomy. The rats were killed after 4 months, and a histomorphometric study and quantification of intraosseous vessels carried out on the sixth lumbar vertebra. The area of the intraosseous sinusoidal capillaries increased after ovariectomy, which also induced a moderate increase in resorption surfaces and osteoid surfaces leading to a decrease of 40% in the trabecular bone volume at the lumbar spine level. This bone mineral loss was completely prevented by tiludronate, which normalized the bone turnover. However, tiludronate was without any effect on intraosseous vascularization. These results indicate that the surface area of the intraosseous sinusoidal capillaries was correlated positively with resorption surfaces and negatively with trabecular bone volume and the number of bone trabeculae. In these experimental conditions, an inhibitor of bone resorption can exert its positive effect on bone mass without normalization of vascularization.

[Diacetylrhein on a postcontusion model of experimental osteoarthritis in the rabbit]. / Etude de la diacetylrheine sur un modèle post- contusif d'arthrose expérimentale chez le lapin.

The "chondroprotective" activity of a drug must be tested not only in vitro but also in vivo. Because this would require several years in humans, animal models of osteoarthritis are used. A closed contusion of the patella caused by the impact of a 1-kg weight dropped from a height of one meter results in osteoarthritis. Twenty-three adult New Zealand rabbits were sacrificed 49 days after the contusion. Cartilages of both condyles and the patella were studied on 6-mu hematoxylin-eosin-stained serial sections. The morphologic osteoarthritis score (sum of gross and microscopic scores) was determined. Mean score was the mean value of scores for both condyles and the patella, whereas total score was the sum of scores at the three sites. The 23 rabbits were divided into four groups: controls (n = 6), controls + diacerhein (n = 5), contusion (n = 6), and contusion + diacerhein (n = 6). Diacetylrhein was given orally (3.5 mg/kg/d) throughout the 49-day interval between contusion and sacrifice. Mean and total scores showed no significant differences between the control, diacerhein, and diacerhein + contusion groups. Scores were significantly lower in the control group as compared with the contusion group (p < 0.03) and in the diacerhein + contusion group as compared with the contusion group (p < 0.05). Diacetylrhein given in as prophylactic treatment under the experimental conditions used prevented contusion-induced cartilage destruction and exhibited a "chondro-protective" effect.