摘要
目的：探讨全髋置换术或修整术时近端骨皮质缺损使用无骨水泥股骨假体的合适长度。方法：采用２５对狗股骨实验模型。（１）在股骨近端前外侧皮质造成５０％直径大小骨皮质缺损，研究其对近端股力学性质的影响；（２）分别使用超过骨缺损区骨干直径１、２、３倍长度的假体，探讨使用无骨水泥股骨假体的合适长度和可行性。结果：近端股骨缺损组最大扭力、最大旋转角度及骨折时能量吸收分别为正常对照侧的４４％±６％、３８％±７％和１５％±５％（Ｐ均＜０．００１）；超过骨皮质缺损区３倍直径长度的无骨水泥股骨假体增强了缺损骨的抗扭力负荷能力，但仅达到正常股骨的５７．８％。结论：通过对无骨水泥人工假体的力学分析，我们认为在已存在近端股骨缺损的全髋置换术或修整术中，对年轻患者可选用无骨水泥假体，其长度应达到缺损区骨干直径的３倍或以上，并避免早期负重；但对年老患者宜选用骨水泥股骨假体。
Objective: To detemine the optimal length of a cementless femoral component in total hip arthroplasty(THA)in the presence of a diaphyseal defect.Methods: The experiment was performed in two phases using 50 canine femora(25 pairs).First,5 pairs of femora with a 50% circular unicortical defect located anterolaterally and their contralateral intact control femora were tested to detemine the weakening imposed by the defects.Second ,the effects of stem bypass distances of one,two, and three times diaphyseal diameter beyond the defect weretested in 20 pairs and compared to contralateral controls with similar defects. All specimens were torsionally stressed to failure on a bilxial materials testing system .Results: Femora subjected to the cortical defect exhibited only 44%±6%,38%±7%,15%±5% of control side maimum torque,angular rotation,and energy absorption to failure, respectively (P<0.001).Onediameter bypass decreased bone strength to 88% of control side maximum torque. Twodiameter bypass showed maximum torque similar to that of the control side. Threediameter bypass improved defect bone torsional strength to 133%, however,it only achieved 58% of strength when compared to intact controls. Conclusion: In cementless femoral components,the boneprosthesis interface is not fully bonded in the early postoperative period.We suggest that uncemented hip arthroplasty may be used in youngpatients who have a defect in the femur,however,threediameter bypass approach may be necessary and the patient should be protected from activities which produce large torsional loads until the bone regains strength.In contrast, for elderly patients the use of cemented femoral components should be advocated to avoid complications related to disuse of immobilization.
出处
《中华骨科杂志》
CAS
CSCD
北大核心
1998年第7期418-422,共5页
Chinese Journal of Orthopaedics
