[Cryosurgery for osteonecrosis of the femoral head in three-leg canine model].

OBJECTIVE

To establish an animal model of osteonecrosis of the femoral head (ONFH) like human.

METHODS

Ten healthy adult three-leg Beagle male dogs weighing (16.0 +/- 1.6) kg were conducted as the animal model of ONFH according to the schedule of cryosurgery designed in advance in which liquid nitrogen, pressurized to 0.5 MPa, was poured into the femoral head for 16.5 minutes. After rewarmed to O degrees C for 10 minutes, the liquid nitrogen was reported into the femoral head for another 16.5 minutes. At the end of the follow-up, the results were reviewed by pathologic check. One dog was conducted as control group.

RESULTS

The first boundary temperature of (-27.9 +/- 4.3) degrees C was higher than the second boundary temperature (-31.3 +/- 4.7) degrees C by -3.4 degrees C, and there was significant difference (P < 0.01). The diameter of the femoral head of (17.7 +/- 1.1) mm was linearly (y = 2.6 - 2.409 x) correlated to boundary temperature by Pearson analysis, and the R rate was 0.977 (P < 0.05). Four dogs in experimental group progressed to collapse of the femoral head like human in the 6th month after operation. The rate of the femoral head collapse rose to 44.4%. In the control group, osteonecrosis was never found.

CONCLUSION

Cryosurgery for osteonecrosis of the femoral head in the three-leg canine model may become a method to establish an animal model of ONFH like human.