Avascular necrosis of the femoral head is frequently observed in growing spontaneously hypertensive rats (SHR), which resembles the pathological findings of Perthes' disease in man. In the incidence of Perthes' disease, it is known that the femoral heads of boys are affected more often than those of girls.
The purpose of this study is to observe the difference of the incidence between male SHR and female. In male SHR, the number of the necrosis at the age of 6, 9, 12, 15 and 20 weeks (14 femoral heads of 7 SHR in each age group) was 0, 1, 1, 9 and 7, respectively. Moreover, the retardation of the ossification in the femoral head was also seen frequently. On the other hand, the necrosis in female SHR was seen only in 4 of 70 femoral heads.
The similarity of the femoral head lesions in SHR and Perthes' disease is discussed in this papper.
