髋臼后壁骨折对髋臼与股骨头之间接触特性的影响

目的 :评价后壁骨折对髋臼与股骨头之间接触特性 -负重面积、负重、应力和应力分布的影响。方法 :用夹具将骨盆标本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、后壁和负重顶区接触特性的变化。结果 :后壁骨折使负重顶区的负重、负重面积和平均应力均显著增加 (P <0 .0 1)。后壁骨折对前壁的负重面积改变不大 (P =0 .5 6) ,但使前壁的平均应力 (P <0 .0 1)和负重 (P <0 .0 5 )均显著减少。后壁骨折显著减少了后壁的负重面积 (P <0 .0 1) ,但对后壁的负重并未产生显著影响 (P =0 .19) ,对平均应力的影响 ,只是在 3 /3骨折后与完整相比才出现统计学上的差异 (P <0 .0 1)。结论 :(1)后壁骨折显著改变了髋臼与股骨头之间的接触特性 ;(2 )后壁 1/3骨折时影响率最大 ;(3 )变化最显著的部位是负重顶区。

The effect of posterior wall acetabular fractures on contact characteristics between the acetabulum and femoral head

Objective: To evaluate the effect of the posterior wall acetabular fractures on the contact characteristics between the acetabulum and femoral head. Methods: Six embalmed pelves 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 for the alteration of the contact characteristics-the load, the pressure, and the distribution of the pressure between the acetabulum and femoral head were recorded. Testing and recording was initially performed with the intact acetabulum. After that, the 1/3,2/3, 3/3 fracture of posterior wall were tested. Results: After the posterior wall of the acetabulum fracturing, the load, the loading area, and the pressure of the weight-bearing dome were significantly increased( P <0.01). The effect on the loading area of the anterior wall was light, but the pressure and the load of the anterior wall were significantly decreased( P <0.01). Although the loading area obviously decreased( P <0.01), there was no significantly effect on the load of the remained posterior wall. Conclusions: The posterior wall fractures of the acetabulum significantly alter the contact characteristics between the acetabulum and femoral head during single-limb stance. The loading area, pressure and load of the hip joint are redistributed after the posterior wall fractures. The change of the weight-bearing dome occurrs significantly. The one-third fracture of the posterior wall resulted in the greatest alteration in joint contact characteristics.