A simple method for establishing an ostrich model of femoral head osteonecrosis and collapse

Abstract

BackgroundThis study aimed to develop a simple method of creating an animal model of non-trauma femoral head osteonecrosis and collapse using African ostriches with weights similar to those of humans.MethodsEighteen African ostriches were subjected to liquid nitrogen cryo-insult in the unilateral femoral head through surgical procedures using homemade cryogenic equipment combined with tract drilling inside the femoral head. Three animals were sacrificed at postoperative weeks 6 and 12, respectively, and the remaining animals were sacrificed at postoperative week 24. Bilateral femoral heads were harvested and subjected to gross observation, histological examination using hematoxylin and eosin staining, and radiographic examination. Micro-computed tomography was performed on a portion of the specimens at postoperative week 24, and angiographic examination of the femoral head was performed before sacrificing the animals.ResultsEight ostriches developed a limp at postoperative week 8, with a mean duration of 16.5 weeks. The postoperative femoral head specimens showed changes in contour and articular cartilage degeneration. Sagittal sectioning of the collapsed femoral head specimens revealed distinct boundaries among the osteonecrotic areas, osteosclerotic areas, and normal trabeculae. Histological examinations revealed active bone resorption in the osteonecrotic area of the subchondral bone, an increased number of fat cells, and active trabecular bone regeneration in the osteosclerotic areas. The postoperative radiographic examinations revealed that the height of the femoral head gradually decreased and progressed to collapse. Micro-computed tomography scans showed the interrupted trabecular bone with an irregular shape in the collapsed femoral head. Compared with the normal samples, angiographic findings revealed interrupted blood supply of the cryo-injured samples in some areas of the femoral heads, blood vessel narrowing, and decreased number of blood vessels in the cryo-injured areas.ConclusionThis study indicates that an animal model of osteonecrotic femoral head progressing to collapse can be established via a simplified method of cryosurgery. This model possesses histological features that are similar to those of humans; thus, it can be used as an ideal animal model for the study of femoral head necrosis.

Pravastatin Protects Against Avascular Necrosis of Femoral Head via Autophagy

“…Formalin-fixed decalcified femoral heads of both sides were embedded in paraffin, sectioned at 5 μm, and stained with hematoxylin and eosin (H&E) (Jiang et al, 2015 ). The sections were evaluated by three independent pathologists in double blind fashion.…”

Advances in experimental models of osteonecrosis of the femoral head

“… 80 ​± ​20% [ 7 , 21 , [22] , [23] , [24] , [25] ] PI Repeated cryo-insult-rewarming procedure under radiographic guidance. 60 ​± ​20% [ 18 , [26] , [27] , [28] ] CI Direct intraosseous injection of pure ethanol. 100% [ 19 ] SVD ​+ ​PI Damage of vascularity and blood circulation around the FH, combined with repeated freeze–thaw cycles.…”

“…However, the bearing capacity of quadruped animals is not comparable to humans. Investigation of bipeds has been limited to geese, chicken, ostrich and emu [ 18 , 19 ]. Although the weight bearing of these animal models is close to human beings, their anatomical structure and physiological characteristics are not.…”

“…In another study, eighteen African ostriches were subjected to liquid nitrogen cryo-insult in the unilateral femoral head. The postoperative femoral head specimens exhibited changes in contour and articular cartilage degeneration [ 18 ]. Thus, bipedal ONFH animal models can also be used to simulate human ONFH.…”

Composite indices of femoral neck strength predicts the collapse of steroid-associated osteonecrosis of the femoral head: a retrospective study

“…Furthermore, the bending strength index (BSI) and the impact strength index (ISI) were calculated according to the average femoral neck width (FNW) and hip axis length (HAL), height, weight and femoral neck DXA-BMD [ 14 ]. Meanwhile, existing studies found that patients with the femoral head necrosis have active bone formation and bone resorption, and have obvious abnormal lipid metabolism [ 15 ]. Therefore, bone turnover markers can reflect the development of non-traumatic ONFH to a certain extent.…”