Research On Mechanism And Therapy In Avascular Necrosis Of Femur Head After Treatment In DDH

Objective:To explore correlation with the predilection sites and pathogenesis on epiphysis'avascular necrosis(AVN) of femur head in the development dislocation of hip(DDH). Methods: From March of 2005 to December of 2007, 18 patients with AVN of femur head after conservative treatment and 6 with AVN after surgical treatment in DDH in our hospital were examined retrospectively about anatomy and biomechanics on acetabular and epiphysis of the femur head. Based on radiography materials, CT slices three-dimensional reconstruction (3DCT) to analyze the predilection site, and research on pathogenesis of epiphysis'AVN of femur head in DDH and summarize the treatment experiences. Results:There are significant difference between conservative and surgical treatment in the predilection sites about the AVN of femur head. After surgery on 18 patients with AVN of femur head after conservative treatment and 6 with AVN after surgical treatment in DDH, according to the grading standard by Zhang and Dai the final results can be divided as excellent in 8 case(27.58%),good in 16 case(s55.17%)and poor in 5(17.25%). Conclusion: Through clinical research we regard that there are significant difference between conservative treatment and surgical treatment in the predilection sites about the AVN of femur head. The larger stress between the acetabular and the epiphysis of the femur head caused by multiple factors induce the AVN of femur head after the treatment of DDH. The destruction of blood circulation during operation causes the AVN of femur head after surgical treatment.