臼顶不同程度台阶状移位对髋臼负重区生物力学的影响

目的采用压敏片技术测量髋臼高位前柱骨折后不同程度台阶状移位对臼顶负重区的生物力学影响。方法取成年男性防腐尸体骨盆标本(含双侧股骨中上段)5具,分为完整骨盆组(I组)、解剖复位组(A组)及1 mm台阶组(B组)、2 mm台阶组(C组)、3 mm台阶组(D组)。用特制夹具将骨盆和股骨固定于单足站立中立位,去除髋关节囊,将压敏片贴于股骨头上,分别测量各组标本髋臼臼顶负重区负重面积、平均压强及峰值压强。所获数据经SPSS18.0统计分析软件进行方差齐性检验,采用最小显著差数法(LSD)多重比较。结果 I组与B、C、D组间在负重面积、平均压强及峰值压强上均有显著性差异(P<0.05、0.01);I组与A组相比差异不明显(P>0.05);B组与C、D两组间均有显著性差异(P<0.05、0.01)。结论臼顶部台阶的存在,使髋关节生物力学行为发生了显著变化,负重顶应力显著增加,负重面积显著减小,单位软骨内应力升高,增加创伤性关节炎发生率。对于涉及臼顶负重区的髋臼骨折,应追求解剖复位。

Biomechanical influence on acetabular dome with step-shaped displacements

Objective To investigate the biomechanical changes in the dome region with different step-shaped displacements of high anterior column acetabular fracture.Methods Five embalmed pelvis plus the proximal femurs were harvested for this study.Before loading,the entire capsule of the hip joint was removed.The pressure-sensitive films were fixed on the surface of the femoral head with 502 glue.Test was initially performed with the intact acetabulum.After the intact pattern(group I)was recorded,sequential conditions such as anatomical reduction(group A),1 mm step-off(group B),2mm step-off(group C) and 3mm step-off(group D) were performed.To these five groups,the loading area,mean and peak pressure in the acetabular dome region were measured with pressure sensitive film,then multiple comparison among five groups were performed with least significant difference(LSD) method.The statistical work was performed with the help of software SPSS18.0.Results Through LSD multiple comparison,there was significant difference between group I and group B,C,D(P<0.05,0.01),and significance difference can be seen between group B and group C,D(P<0.05,0.01).There was no significant difference between Group I and group A(P>0.05).Conclusions From the view of biomechanics,significant changes emerge when step-shaped displacements come out which afflicting high anterior column acetabular fracture.Fracture must be anatomically reduced while weight-bearing area involved.