Nontraumatic osteonecrosis of the femoral head
(ONFH), also known as avascular necrosis, is a refractory and progressive disease that commonly affects young patients and has a poorly understood etiology and pathogenesis .
A link between systemic steroid use and the development of osteonecrosis of the femoral head
has been well documented, but the exact mechanism of action is still debated.
Avascular necrosis of the femoral head
, flared long bone metaphysis/epiphysis, enlarged capitulum of the distal humerus have also been reported.
"Dysplasia can make the labrum vulnerable to tears due to instability of the femoral head
within the socket," Dr.
Ventro-dorsal hip radiograph was taken which revealed bilateral hip dysplasia with flattened femoral head
, shallow acetabulam and subluxation (Fig.1).
(35,52) More than 90% of non-traumatic hip ON cases are estimated to occur secondary to alcohol and corticosteroid use (54) possibly via mechanisms that result in fatty infiltration of bone marrow leading to intraosseus hypertension, vascular compression, and diminished vascularity to the femoral head
(8-10) In children more than two years of age who walk on the dislocated joint, in the case of persistent excessive anteversion of the femoral neck and femoral head
displacement of more than one-third of the iliac width, both femoral and innominate osteotomies should be considered.
AVN was monofocal in three (34%) patients and it affected the bilateral knee or femoral head
in six patients (66%).
Regarding the diameter of the femoral head
, Igbigbi & Msamati (2000) examined radiographs and found higher values for both the vertical diameter (48.30 [+ or -] 3.51 mm, p = 0.001) and transverse diameter (50.55 [+ or -] 3.32 mm, p<0.001) of the head of the femur in males compared to females.
Avascular necrosis/osteonecrosis of femoral head
is demonstrated as a photopenic area on bone scintigraphy.
Containment can be achieved by positioning the extruding femoral head
in a more covered position.