Femoral head loss of blood supply 8 hours to necrosis

The majority of avascular necrosis are and trauma, trauma causes of osteonecrosis of the femoral head can be divided into: the fracture of the femoral neck SAC, compressed fractures of the femoral head, these are because of damaged blood vessels. These vascular damage, the femoral head in whole or in part loss of blood supply and blood flow after 8 hours after interruption caused ischemic necrosis. Thus, in a displacement of the femoral neck fractures, femoral head necrosis can occur very early. Avascular necrosis of femoral neck fractures accounted for 85% and non-displaced fracture of 15%-25%.

There are reports that the chanter fracture PIN after also avascular necrosis occur because of the femoral head pin, because the PIN may hurt and lateral epiphyseal arteries. This can cause vascular injury of femoral head ischemia and necrosis, and finally in the upper portion of the weight-bearing parts of the femoral head has subsided. Sometimes a direct attack on the hip also avascular necrosis.

Traumatic osteonecrosis of the pathogenesis of more complicated for us to attract his cause for a review of the features:

(A) mechanical strength decreased bone structure kidney dialysis after parathyroid hormone level elevation, making the subchondral bone structure updates faster, the newborn disordered bone matrix cannot assume normal weight, resulting in a micro-fractures increased intra-pressure. Excessive bone osteoporosis will easily increase the number of micro-fractures cause pressure. Alcohol can promote bone osteoporosis, reduce bone mechanical strength. Addition of alcohol and hormone itself on bones have toxic effects.

(Ii) the lesions of femoral epiphysis spondylolisthesis visible in hypothyroidism, the use of growth hormone and radiotherapy. Femoral epiphysis spondylolisthesis is above shift outward epiphysis, metaphysis swing allows lateral impact epiphyseal arteries, the blood of epiphysis.

(Iii) relating to disease and vascular lesion: 1 can be divided into external and intraosseous vascular obstruction. Blocking may occur: arterial, venous and capillary bed because avascular necrosis of the good fat in diabetes and alcoholics, usually associated with high cholesterol, hypertension and coronary atherosclerosis, some would call it "avascular necrosis of the hip coronary disease". Others think the obstructive Vasculitis due to immune complex antibody deposits. To the blood vessel wall induced allergy. Radioactive Arteritis, intraosseous obstructive Vasculitis related to necrosis.

(Iv) the Medullary cavity pressure increases as the femoral head is a confined space, the space within any enlargement will make intra-pressure increase, pressure vessels, necrosis. Hormones can cause bone marrow fat cell hypertrophy, stacked, intramedullary pressure, microvascular compression bone structure, cause a loop.

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