人工全髋关节置换术中偏心距重建对髋关节功能的影响

Effect of offset reconstruction to hip function in total hip arthroplasty

目的比较标准股骨假体行人工全髋关节置换术中股骨假体颈长和股骨距保留对偏心距重建的作用，并分析偏心距重建对软组织平衡的影响。方法68例（71髋）行初次全髋关节置换术并获得随访。术中确定双下肢等长、髋关节稳定及周围软组织紧张度适中。术后采用Harris评分评估手术结果，Cybex-6000等速测定患髋外展肌力，通过手术记录和X线片测量获得偏心距、股骨距、假体颈长、外展肌力臂，用SPSS11．5统计学软件包对数据进行分析。结果假体颈长对偏心距的影响较股骨距大（P＜0．01），并与偏心距呈正相关关系（r=0．642，P＜0．001），但两者对于Harris评分影响的差异无统计学意义（P〉0．05）。股骨头坏死患者术后的偏心距较髋关节骨关节炎患者（P＜0．01）和股骨颈骨折患者小（P＜0．01）。颈于角与偏心距外展肌力臂比呈正相关关系（r=0．25，火0．05）。偏心距重建较好的髋关节术后外展肌力较偏心距重建不足者优（P＜0．05），且两者呈相关关系（r=0．29，P＜0．05）。结论偏心距的重建在全髋关节置换术软组织平衡中主要起到增强术后外展肌力的作用。采用标准股骨假体重建术后股骨偏心距，股骨假体颈长对人工全髋关节置换术后偏心距的重建作用大于股骨距的保留，在诸多影响因素中起到关键作用。

To compare the contribution of femoral component neck length and femoral calcar remaining to offset construction in total hip arthroplasty with standard femoral component, and analysis the effect of offset reconstruction to soft tissue balance. Methods Seventy-one hips of 68 patients （ineluding 30 males, 38 females; with the mean age of 63.5 years） which had undergone primary total hip arthroplasty were followed up. Lower limb length equalization, postoperative hip stability and soft tissue tension around the hip were confirmed during the operation. The postoperative Harris score was used to evaluate the surgical results. Measure the strength of abductor with constant velocity through Cybex-6000, and obtain femoral offset, femoral calcar remaining, femoral component neck length as well as abductor lever arm via operation record and X-ray. All the data were analyzed with SPSS 11.5. Results Femoral neck length had significant effect on femoral offset compared to femoral calcar （P〈 0.001）, and positive correlation with the offset. But in Harris score, no significant difference was observed （P 〉0.05）. The postoperative femoral offset of the patients with femoral head osteonecrosis was less than that of the patients with hip osteoarthrosis （P〈 0.01 ） and femoral neck fracture （P〈 0.01）. Femoral neck-shaft angle also positively correlated with the abductor lever arm and femoral offset （r=0.25, P〈 0.05）. The adductor muscle force in the patients whose offset was well reconstructed was significantle stronger than that in the patients failed to reconstruct the offset（P〈 0.05）, and the adductor muscle force had positive correlation with femoral offset （r=0.29, P〈 0.05）. Conclusion The role of femoral offset in soft tissue balance of total hip arthroplasty is to enhance the postoperative adductor muscle strength. Restoring the femoral offset with standard femoral component, and the fact that the femoral neck length is more important than femoral calar remaining in femoral offset restoration are the key factors in offset reconstruction.