[Morphology and immunohistochemistry of traumatic and non-traumatic necrosis of the femoral head].

Objective: To comprehend the pathological features and possible pathogenesis ot avascular necrosis of the femoral head (ANFH) by morphology and immunohistochemical observation of osterix (OSX) and adiponectin through in vitro traumatic and non-traumatic ANFH specimens, so as to provide a theoretical basis for clinical treatment.

Methods: Sixty-six ANFH specimens were collected from 66 clinical cases undergoing hip replacement surgery. Twenty-four cases of traumatic ANFH (group A) included 17 males and 7 females, aged 21 to 70 years with an average of 56.5 years; 23 cases of steroid-induced ANFH (group B) included 16 males and 7 females, aged 56 to 72 years with an average of 61 years; and 19 cases of alcoholic ANFH (group C) were males, aged 55 to 67 years with an average of 58.5 years. Bone tissue was got from weight-bearing and non-weight-bearing area of the femoral head respectively. The basic pathological changes was observed by HE staining under the optical microscope, and the percentage of empty bone lacuna and the percentage of trabecular bone area were calculated. The morphological changes of ANFH in different groups were observed by scanning electron microscope (SEM). OSX and adiponectin expression were detected by immunohistochemical technique.

Results: Gross of the femoral head surface in each group was rough, collapse, articular cartilage loss, osteophyte formation; cross section: dark red in group A, and yellow in groups B and C. HE staining showed that weight-bearing area of ANFH have similar morphological features in three groups. In non-weight-bearing area of groups B and C, the fat cells in bone marrow markedly increased and were hypertrophic; however there were more fibrous tissue in group A. There were statistically significant differences (P < 0.001) in the percentage of empty bone lacuna of the weight-bearing and non-weight-bearing area among three groups. There were no statistically significant differences (P > 0.05) in the percentage of trabecular bone area among three groups. The SEM observation showed that three groups had similar pathological changes. Brown granules for OSX and adiponectin positive substance were mainly located in the osteoblast of bone marrow of the femoral head. There was statistically significant difference (P < 0.05) in the average absorbency (A) value of OSX between group A and groups B, C, but there was no statistically significant difference (P > 0.05) between groups B and C. While there was no statistically significant difference (P > 0.05) in the A value of adiponectin among three groups.

Conclusion: Hormones and alcohol necrosis have more obviously fatty degeneration, but the repair capacity of traumatic femoral head necrosis is stronger than that of hormones and alcohol necrosis. Alcohol and hormones have inhibitory action on the OSX-mediated osteogenic differentiation. Hormones and alcohol may not affect osteoblast expressing adiponectin and its receptors.