【作者】 刘胜厚；

【导师】 王韶进；

【作者基本信息】 山东大学 ， 外科学， 2009， 硕士

【摘要】 目的对比长短柄假体置换治疗高龄粉碎性粗隆间骨折的短期临床疗效,探讨股骨矩不同处理方式对长柄假体置换的临床疗效的影响;建立长短柄假体置换治疗高龄粉碎性粗隆间骨折三维有限元模型,对股骨、水泥型长短柄假体、骨水泥的应力分布趋势、大小进行研究以指导临床工作。资料与方法山东大学齐鲁医院2002年5月～2007年5月期间54例(54髋)高龄粉碎性粗隆间骨折行水泥型人工髋关节置换手术,根据假体类型分为两组,第一组为长柄假体置换组31例,第二组为普通柄假体置换(即短柄组)组23例。手术方法基本同常规假体置换,区别在于对股骨矩部位的处理,依据股骨矩部位的骨折情况,采取三种方法即水泥重建股骨矩、钢丝缝扎转子间嵴间接复位股骨矩、钢丝环扎股骨矩。随访术后一年及最近一次髋关节Harris评分,并行髋关节X线检查,观察假体周围影像学表现。在临床随访获得满意疗效的基础上,利用医学数字图像通讯标准DICOM3.0,及Mimics图形处理软件准确地生成股骨特征结构轮廓,再利用CAD建模软件Unigraphics完成股骨三维实体的真实重建,然后建立不同长度人工髋关节股骨假体、骨水泥三维实体模型。最后利用有限元分析软件ABAQUS6.5分别建立股骨、骨水泥和假体的三维有限元模型,进而对模型的应力进行有限元分析,研究股骨和长短柄人工髋关节股骨假体、骨水泥的应力分布和大小。结果①长柄假体置换组(4#)31例,除1例死亡外均获随访,平均随访时间28个月,术后一年Harris评分66～95分(平均83.7分),优良率86.67%;普通假体置换组(3#)23例均获得随访,平均随访时间31个月,术后一年Harris评分57-91分(平均78.2分),优良率82.6%;两组差异无统计学意义。②X线显示长柄假体置换组经随访出现3例异位骨化,均为Brooker分级Ⅰ级,两例出现假体周围透亮带,但宽度小于2mm;除一例股骨矩部位畸形愈合外,股骨矩骨折愈合均满意;普通柄假体置换组2例出现异位骨化,均为Brooker分级Ⅰ级,一例出现假体周围透亮带,宽度小于2mm;股骨矩骨折愈合均满意。③长柄假体置换股骨矩三种不同处理方式在术后卧床时间方面水泥重建组明显长于另外两组,而术后功能对比无统计学意义。④长短柄人工髋关节假体的应力分布为假体颈的上部和中下部,接近颈干交界处各有一个应力集中区,峰值分别为3#169.9Mpa、207.5Mpa;4#191.5Mpa、227.4Mpa;假体柄颈干交界处、远端内外侧各有一个应力集中区,峰值分别为3#85.91Mpa、56.11Mpa、121.83Mpa,4#108.52Mpa、94.13Mpa、182.426Mpa,⑤粗隆间骨折行髋关节置换后剩余股骨应力分布规律为近端向远端应力逐渐增加,至股骨干内外侧中下段1/3交界处集中明显,向末端再次减小,内外侧峰值分别为3#83.35Mpa、96.86Mpa;4#82.11Mpa、95.88Mpa。⑥短柄假体对应的骨水泥一假体柄界面近末端内外侧各形成一应力集中区,峰值分别为10.9Mpa、21.3Mpa,长柄假体对应的该界面在中段内侧及远端内外侧各形成一应力集中区,峰值分别为4.78Mpa、2.48 Mpa、14.83 Mpa。⑦重建股骨矩部位骨水泥的内外部两个界面具有相同的应力分布规律,即厚薄水泥过渡区域后内侧与股骨矩截骨面接触部位为应力集中区,内外部峰值分别为3#4.31Mpa、10.06Mpa,4#6.03Mpa、13.67Mpa。结论1.水泥型长、短柄假体置换治疗高龄粉碎性粗隆间骨折近期临床疗效均满意,对比无统计学差异,但远期效果有待研究。2长柄假体置换治疗粉碎性粗隆间骨折,无论选择何种方法处理股骨矩,短期临床疗效不受影响。3.高龄粉碎性粗隆间骨折行人工关节置换后剩余股骨与人体正常股骨应力分布规律相似。但置换后对比发现长柄假体置换对股骨应力分布的影响更小,更适合人体股骨生物力学要求。4.长短柄股骨假体的应力分布规律无明显差异,且与常规置换后假体应力分布相似,区别在于粉碎性粗隆间骨折置换模型中的假体柄近端内侧增加了一较小的应力集中区。5.水泥重建股骨矩不会发生水泥断裂,没有改变剩余股骨的应力分布规律,从生物力学角度考虑,不会因此造成假体松动,符合生物力学要求。6.短柄假体置换后致使骨水泥-假体柄间的界面应力分布改变明显,其峰值超过了水泥疲劳强度,松动几率明显增加;而长柄假体置换后该界面应力分布规律与常规假体置换后类似,故治疗高龄粉碎性粗隆间骨折水泥型长柄假体置换远期松动几率可能低于短柄假体置换。更多还原

【Abstract】 Objective: To investigate the curative effect of cemented long stem and short stem prosthetic replacement in comminuted intertrochanteric fracture of aged patients, and to compare it between long and short prothesis, meanwhile, to reserch the influence on the curative effect of different methods to deal with the calcar femorale; To analyze the stress of rest femur, long and short stem prothesis, cement by establishing 3-D FE model then to provide rational suggestions for clinic.Materials and methods : 54 cases (54 hips ) with comminuted intertrochanteric fracture were performed cemented prothetic replacement in Shandong university Qilu hospital during 2002-5 to 2007-5, who are divided into 2 groups, one is long stem prothesis group(4#) including 31 cases, the other is short stem prothesis group (3#) including 23 cases. All patients underwent the similar Surgical method with the conventional replacement, but the only difference is that there are three ways to deal with the calcar femorale in the operation of comminuted intertrochanteric fracture including reconstruction with cement, transfixion with titanium wire, and cerclage with titanium wire. The followed-up content include the first year and the recent function evaluated by Harris scores, and the X-rays of hips. In the base of satisfactory curative effect, we use graphics processing software Mimics to deal with the CT digital image file, and reconstruct the three-dimensional entity of femur with CAD modeling software Unigraphics. After that we establish the 3-D modle of long stem and short stem prothesis and mantle layer of cement. Finally we establish the three-dimensional finite element model of those materials, and then impose the boundary conditions of force, set up the material parameters, accordingly we do finite element analysis on these model in stress .Result:①31 cases in long stem group except 1 died were followed up for an average of 28 months. The first year Harris score was 66-95, average 83.7, and the rate of excellent and good was 83.7 percents . 23 cases in short stem group were all followed up for an average of 31 months. The first year Harris score was 57-91, average 78.2, and the rate of excellent and good was 83.7 percents . The first year Harris score of two groups had no significant difference.②The follow-up X-ray showed three cases of heterotopic ossification in the long stem prosthetic replacement group, all of them were Brooker I, and two cases occurred radiolucent zone around the prothesis, but the width was less than 2mm; In addition to a case of malunion, the fractures of calcar femorale healed well. In the short stem group, there were 2 cases of heterotopic ossification and both were Brooker I, and 1 cases occurred radiolucent zone around the prothesis, but the width was less than 2mm; and all of fractures of calcar femorale healed well.③After repalcing with long stem prothesis, we found the method of cement reconstruction to calcar femorale was significantly longer than the other two methods in bed time , but there was no significant difference in short-time curative effect.④In the prothetic finite element model, there were two stress concentration areas on neck, one appeared on the superior, the other was on the inferior middle part of neck and near to the conjunction of femoral neck and shaft, the peak value was 3#169.9Mpa, 207.5Mpa; 4# 191.5Mpa, 227.4Mpa respectively; and there were three stress concentration areas on stem, one appeared on the conjunction of femoral neck and shaft, and the other two are on the bilateral distal part of stem, the peak value was 3#85.91Mpa, 56.11Mpa, 121.83Mpa; 4#108.52Mpa, 94.13Mp, 182.426Mpa respectively.⑤On the FEM of rest femur, the rule of distribution was that stress gradually rised from proximal to distal, it got to concentration on bilateral lower 1 / 3 of femoral shaft, then once again reduced to the end, and the peak value was 3#83.35Mpa, 96.86Mpa; 4#82.11Mpa, 95.88Mpa respectively.⑥The stress distribution of interface between bone cement and prothetic stem was different between long and short stem.The distribution of short stem was that there were only two stress concentration areas which were in the the correlative area with distal end of the prothesis, the medial peak value was 10.9Mpa and the lateral peak value was21.3 Mpa. The distribution of long stem was that there was a stress-concentration peakin the middle of medial interface, and there were two stress concentration areas in thedistal end of bilateral interface. The peak value was 4.78Mpa, 2.48 Mpa, 14.83 Mparespectively.⑦The interior and exterior interfaces of bone cement which was used toreconstruct the calcar femorale had the similar rule of stress distribution, there was astress concentration zone in the transition region between thick and thin cement, itwas just in the medial posterior of cement which was correlative to the fracturesurface of calcar femorale, and the peak value was 3#4.31Mpa, 10.06Mpa,4#6.03Mpa ,13.67Mpa respectively.Conclusion: 1.The short-term currative effect of prothetic replacement for treatingcomminuted intertrochanteric fracture of aged patients is satisfactory, there is nosignificant difference between long and short stem, but the long-term follow up needto be done.2. The short-term currative effect is not affected whatever the calcar femorale is dealtwith for long stem prothetic replacement.3.The stress distribution of rest femur after prothetic replacement is similar to thenormal femur. But the peak value and the range of the concentration area are higherthan normal femur. We find that long stem replacement effects stress distributionsmaller and it is consistent with the biomechanical requirements of human femur bycontrast.4.There is no significant difference between long and short stem in the rule of stressdistribution.of prothesis, and the rule is similar to normal replacement, but there is anadditional small stress concentration area in the medial of proximal end of prothesison the FEM of comminuted intertrochanteric fracture.5.The calcar femorale reconstruction with bone cement is consistent withbiomechanical requirment, because it dosen’t change the rule of stress distribution offemur and the cement will not rupture, prosthesis will not loosen for this reason.6.The interface stress distribution between cement and prothetic stem changes acutelyin short stem prothetic replacement, the peak value of the stress-concentrationoversteps the fatigue strength of bone cement, so the loosening rate will be higher. However, interface stress distribution between cement and prothetic stem is similar to normal arthroplasty, so its loosening rate may be lower than the short stem in treating comminuted intertrochanteric fracture of aged patients.更多还原