髋臼后壁骨折对髋臼与股骨头之间应力的影响

目的　评价髋臼后壁骨折对髋臼与股骨头之间应力的影响。　方法　 6具完整骨盆及近侧 1 3股骨标本 ,用夹具将其固定于单足站立骨盆中立位 ,在LDS - 5 0 0试验机上加载至体重的 5 6,维持 2min。用压敏片依次测量完整髋臼、后壁 1 3 ,2 3 ,3 3骨折时髋臼前壁、后壁和负重顶区的应力和应力分布变化。　结果　后壁骨折使负重顶区的平均应力显著增加 (P <0 .0 1) ,后壁完整时为 ( 1.0 9± 0 .3 1)MPa,1 3骨折时为 ( 1.5 0± 0 .3 7)MPa ,2 3骨折时为 ( 1.67± 0 .2 1)MPa ,3 3骨折时为 ( 1.72± 0 .3 2 )MPa ;而使前壁的平均应力显著减少 (P <0 .0 1) ,完整时为 ( 1.95±0 .4 5 )MPa ,1 3骨折时为 ( 1.4 3± 0 .5 0 )MPa,2 3骨折时为 ( 1.3 4± 0 .5 2 )MPa ,3 3骨折时为 ( 1.4 0±0 .61)MPa ;对残余后壁的平均应力影响不大。　结论　后壁骨折显著改变了髋臼与股骨头之间的应力和应力分布 ;后壁 1 3骨折时影响率最大 ;变化最显著的部位是负重顶区

Influnence of posterior wall fractures of the acetabulum on the pressure between the acetabulum and the femoral head

Objective To evaluate the effect of the acetabular fractures of posterior wall on the pressure between the acetabulum and the femoral head. Methods Six embalmed pelvis and articulated proximal 1/3 of the femurs were harvested for this study. The position of the pelvis and proximal femur during testing simulated the single leg stance phase of gait. The pressure sensitive films recorded the pressure, and the distribution of the pressure between the acetabulum and the femoral head. Testing was initially performed with the intact acetabulum. After the intact patterns were recorded, the 1/3,2/3, and 3/3 fracture of the posterior wall were tested. Results After the posterior wall fracture of the acetabulum, the pressure of the weight bearing dome was significantly increased ( P < 0.01 ). The pressure of the anterior wall was significantly decreased ( P < 0.01 ). There was no significant effect on the pressure of the remained posterior wall. Conclusions The posterior wall fractures of the acetabulum significantly alter the pressure between the acetabulum and the femoral head. The pressure of the hip joint is redistributed after the posterior wall fractures. The one third fracture of the posterior wall results in the greatest alteration in joint pressure.