Acceso usuarios
Sergio Martínez Álvarez, D. Azorín, Tomás Epeldegui Torre 
, F. Forriol Brocal
Objective: To establish a reproducible experimental model in lambs to cause avascular necrosis of the femoral head.
Material and Methods: We used 21 lambs, aged between 6 and 22 weeks. In the first group (13 lambs), the ilioinguinal musculature was sectioned, injecting a sclerosing substance and ligating the pericapsular vessels in the femoral neck by wire cerclage. In the second group (9 lambs), the femoral neck was ligated using a plastic loop and sectioning of the round ligament. No type of immobilization was used. The animals were sacrificed, depending on the group, between 15 and 34 weeks. We conducted radiographic, gross, and histological studies.
Results: The femoral heads showed a secondary site of ossification and thinning of growth plate cartilage, more severe in the animals with course longer than 7 weeks after vascular injury. Increased bone density in the femoral head, with cephalic flattening, irregular arrangement of the physis and hypergrowth of the greater trochanter was observed. We found necrosis of joint cartilage without evidence of vascular invasion.
of the hypertrophic area of cartilage growth. We found fibrotic areas in the metaphysis.
Conclusion: Experimental vascular injury in the hip of immature lambs causes substantial changes in joint cartilage, the secondary site of ossification, the growth physis and metaphysis.
