胫骨侧徒手截骨的膝关节置换术后力线测量及其影响因素分析

Measurement of the tibial alignment after total knee replacement without the extramedullary cutting guide

目的:分析人工全膝关节置换术(total knee arthroplasty,TKA)中胫骨侧徒手截骨相较于传统髓外定位架截骨的准确性差异及其影响因素。方法:回顾性选取2012年2月至2016年4月北京大学第一医院收治的初次TKA患者76例(96膝),其中胫骨侧徒手截骨组40例(54膝)、胫骨侧髓外定位组36例(42膝),手术均由同一组医生完成。手术前后分别拍摄下肢站立位膝关节前后位X线片,对X线片进行术前胫骨角(anatomical tibial angle,AT)、胫骨平台后倾角(posterior plateau slope angle,PSA)及术后冠状位胫骨假体角(tibia component angle,TCA)和PSA的测量,同时记录手术开始时刻、手术时长(min)、为术者当日第几台手术等数据。采用相关性分析、t检验及卡方检验对结果进行统计学分析。结果:两组患者间年龄、性别、患侧体重指数(body mass index,BMI)、术前AT、术后TCA、术前PSA、术后PSA差异均无统计学意义(P>0.05)。胫骨侧徒手截骨组和髓外定位组术后90-TCA≥3°分别有17膝(31.5%)和13膝(31.0%),差异无统计学意义(P=0.956)。两组患者术后TCA与其年龄、性别、BMI、手术侧别、手术开始时刻、手术时长(min)、手术为术者当日第几台等因素均无相关性(P>0.05)。根据术前90-TCA范围分别将两组患者在各自组内进一步分为4个亚组(0°≤90-AT<3°、3°≤90-AT<5°、5°≤90-AT<8°、90-AT≥8°),4个亚组术后90-TCA在徒手截骨组和髓外定位组间差异均无统计学意义。但数据变化趋势提示,徒手截骨组患者随术前90-AT增大,术后90-TCA逐渐趋于±3°以内;而髓外定位组患者随术前90-AT增大,术后90-TCA≥3°的比率明显升高;当术前90-AT≥8°时,徒手截骨组对于下肢力线矫正要优于髓外定位截骨组(90-TCA在±3°以内的比率分别为71.4%及42.9%)。结论:TKA时胫骨侧徒手截骨法与传统髓外定位法对冠状位的评估准确性无明显差异,且其与患者性别、年龄、BMI、手术侧别、术者疲劳程度均无相关性。术前已存在严重的膝关节畸形(90-AT≥8°)者,徒手截骨对于下肢力线矫正要优于传统的髓外定位架截骨。

Objective： To evaluate the accuracy and analysis of the influencing factors of the tibia prosthetic coronal alignment after total knee arthroplasty without tibia extramedullary cutting guide. Methods：In the study,76 patients（ 96 knees） who had primary total knee arthroplasty in Peking University First Hospital from February 2012 to April 2016 were selected retrospectively. All of the cases were performed by the same experienced orthopedic surgeon team. The patients were divided into 2 groups randomly：tibia cutting without guide group and tibia cutting with extramedullary guide group. Lower extremity standard anterior and posterior X-ray films of the knees were taken before and after surgery,and the anatomical tibial angle（ AT）,the posterior slope angle（ PSA） before and after surgery,the tibia component angle（ TCA） were measured in the X-ray films. We also recorded the beginning and finishing time of the operation,the operation sequence of the day respectively at the same time. The data were analyzed by correlation analysis,t test and chi square test between the two groups. Results： The age,gender,body mass index,AT/PSA before the surgery and TCA/PSA after the surgery of the two groups were no significant differences（ P〉 0. 05）. The rate of 90-TCA ≥ 3° was 31. 5%（ 17 knees） and 31%（ 12 knees） respectively,there were no significant differences（ P = 0. 956） between the two groups. The postoperative TCA of two groups was not correlated with age,gender,body mass index（ BMI）,operation side（ P〉 0. 05）,there was also no correlation between the postoperative TCA and the start time of the operation,the whole operation time,and the operation sequence of the day（ P 〉0. 05）. The two groups were divided into subgroups according to 90-AT before the operation（ 0° ≤ 90-AT〈 3°,3° ≤90-AT〈 5°,5°≤ 90-AT〈 8°, 90-AT ≥8°）,and there was no difference among them. But we found there was a much higher rate of 90-TCA〈 3° in the group without cutting guide than the group with extramedullary guide when 90-AT ≥8° before the surgery（ the rates were 71. 4 % and42. 9%,P〈 0. 05）. Conclusion： There is no significant difference of the tibia prosthetic coronal alignment accuracy between the tibia cutting without guide and the traditional extramedullary guided bone cutting by experienced surgeons. Only if when patients already have suffered severe malformation of knee joint（ 90-AT ≥8°） before the operation,tibia cutting without cutting guide is more effective to rectify the tibia prosthetic coronal alignment.