Estimation of Femoral Head Collapse in Adult Patients with Non-traumatic Occlusion Femoral Head Necrosis

Objective:By using clinical trial to investigate the relationship between the location and size of the femoral head necrosis and femoral head collapse.Methods: From Oct.2006 to Oct.2008,a clinical trial on 12 cases of femoral head necrosis(15 hips) receiving prosthetic replacement of joint was performed.Results: The average volume of the whole femoral head,which was measured by splitted femoral head,was 50.0 cm3(35.6-59.4 cm3).The average volume of femoral head necrosis area was 21.6 cm3(12.0-29.8 cm3).The average ratio of the volume of femoral head necrosis area on the whole femoral head(simply named the ratio of necrosis volume) was 43.5%(26.6%-64.3%).The ratio of necrosis volume in 9 hips,4 hips,and 2 hips was more than 40%,30%-40% and less than 30%.The volume of femoral head necrosis area in 8 and 6 hips was 25-35 and 36-45 cm2.The ratio of the volume of femoral head necrosis area in 13 hips was more than 50%.Conclusion: The size of necrosis is closely correlated with the risk of femoral head collapse.When the volume ratio of femoral head necrosis is more than 30%,the rate of femoral head necrosis collapse is 87% and the collapse has high risk.When the volume ratio of femoral head necrosis is less than 30%,the location of collapse focus has a key role in the progression of pathogenetic condition.When the surface area of necrosis is more than 25 cm2 and the ratio of surface area of necrosis is more than 50%,the rate of femoral head necrosis collapse is 87% and the femoral head necrosis has high risk.