- See:
Blood Supply to Femoral Head:
- Discussion:
- there are certain areas of bone in which vascular supply is precarious;
- these areas are subject to infarction and avascular necrosis;
- three such regions are head of femur, body of talus, & scaphoid;
- they have the common feature that a very large portion of their total surface is covered with articular cartilage through which vessels do not penetrate;
- blood supply for these bones enters through very restricted spaces, & there is limited collateral circulation;
- when principal route of the circulation to these bones is interrupted by trauma or disease, the collateral circulation
is inadequate and necrosis ensues;
- avascular necrosis occurs in other bones, particularly body of talus,
scaphoid, the lunate, and the head of the
second metatarsal;
- occasionally, it develops in multiple areas in the same patient;
- this condition has been found to be frequent complication of prolonged
steroid therapy used in patients with kidney transplants;
- interference w/ blood supply to femoral head results in infarction that may involve the entire head; more
frequently, it is limited to a segment of the head;
- in infarcted area, there is death of marrow elements & of
osteocytes;
- bone death is recognized histologically by disappearance of osteocytes from their lacunae;
- following infarction, there is an attempt at revascularization that extends inward from the adjacent viable bone;
- this revascularization process is very slow in the femoral head;
- hyperemia of surrounding bones causes osteoporosis of living bone, while infarcted bone retains
its density and thus appears whiter or denser on roentgenogram;
- as vessels approach necrotic area,
osteoclastic resorption of dead bone may so weaken the femoral head that a portion of it will collapse,
resulting in an irregular articular surface that sets the stage for painful degenerative arthritis;
- Inciting Causes Include:
-
Femoral Neck Frx:
- distention of hip joint capsule by fluid or pus may produce pressures that
exceed epiphyseal marrow pressure & thereby cut off its circulation;
-
Posterior Hip Dislocation
-
Steroids
- especially large doses of steroids may be directly related to AVN in large joints;
- ETOH
-
Gout
- Diabetes
-
Sickle Cell Anemia:
-
Gaucher's disease
- Decompression Sickness
- infarction can also occur in the shafts of the long bones, probably from emboli in the
nutrient artery,
as seen after caisson disease when nitrogen bubbles become entrapped in the marrow vessels;
-
SCFE
-
Legg-Calve-Perthes' Disease;
- occurs most often in male children between the ages of 5 and 10;
- one theory of its cause is compression of capsular vessels from swelling due to unrecognized trauma;
- Transplant Surgery:
- occurs in 3% of patients after cardiac transplant surgery, but may occur in upto 25% of patients following renal transplantation;
- cyclosporine is most responsible for decreasing the incidence (most likely by decreasing the need for steroids);
- average time of onset is 5 months post surgery;
-
AVN in Pregnancy: (see
considerations in pregnancy)
Osteonecrosis of the femoral head during pregnancy.
Zolla-Pazner, S.; Pazner, S. S.; Lanyi, V.; and Meltzer, M.
J. Am. Med. Assn., 244: 689-690, 1980.
Osteonecrosis of the femoral head during pregnancy.
Lausten, G. S.
Arch. Orthop. and Trauma Surg., 110: 214-215, 1991.
Aseptic necrosis of the femoral head during pregnancy.
Myllynen, P.; Makela, A.; and Kontula, K.:
Obstet. and Gynec., 71: 495-498, 1988.
Osteonecrosis of the femoral head associated with pregnancy. Report of three cases.
Pellicci, P. M.; Zolla-Pazner, S.; Rabhan, W. N.; and Wilson, P. D., Jr.
Clin. Orthop., 185: 59-63, 1984.
Avascular necrosis of bone: a common serious complication of allogeneic bone marrow transplantation.
Intra-osseous pressure and oxygen tension in avascular necrosis and osteoarthritis of the hip.
Role of impairment of blood supply of the femoral head in the pathogenesis of idiopathic osteonecrosis.
Current concepts on the pathogenesis of osteonecrosis of the femoral head.
Role of impairment of blood supply of the femoral head in the pathogenesis of idiopathic osteonecrosis.
Intraosseous pressure, oxygenation, and histology in arthrosis and osteonecrosis of the hip.
Intra-osseous pressure and oxygen tension in avascular necrosis and osteoarthritis of the hip.
Intraosseous arterial architecture in nontraumatic avascular necrosis of the femoral head. Microangiographic and histologic study.
A microangiographic study of idiopathic osteonecrosis of the femoral head.
Selective digital subtraction arteriography in necrosis of the femoral head.
Risk factors of avascular necrosis of the femoral head in patients with systemic lupus erythematosus under high-dose corticosteroid therapy.
Natural history of nontraumatic avascular necrosis of the femoral head.
Natural history of nontraumatic avascular necrosis of the femoral head.
Factor V Leiden and Prothrombin Gene Mutation: Risk Factors for Osteonecrosis of the Femoral Head in Adults.
