股骨峡部在非骨水泥型全髋关节置换中的作用

Effects of femoral isthmus on cementless total hip replacement

背景:非骨水泥型髋关节置换术前计划中常用的模板测量法受诸多因素的影响准确性不高。有研究表明股骨峡部髓腔在髋关节置换中起着重要的作用,影响着股骨假体的安置和置入后的稳定。目的:观察CT峡部测量股骨峡部在非骨水泥型全髋关节置换中的作用。方法:收集4例尸体股骨的CT影像及额状解剖面,分析股骨假体与股骨峡部紧密压配及与皮质骨的接触情况。CT测量50例(55侧)初次行全髋关节置换患者的股骨峡部最长髓腔内径、最小髓腔内径及皮质厚度;利用最小髓腔内径预测假体型号。采用模板测量法作为对照。结果与结论:3例尸体股骨假体可在股骨峡部紧密压配接触到骨皮质。55例的峡部最长髓腔内径大小为8.2～22.4mm,平均(14.2±3.1)mm;峡部最小髓腔内径为6.1～17.9mm,平均(10.2±2.9)mm;皮质厚度2.7～12.7mm,平均(7.5±1.8)mm。利用CT峡部测量法预测假体存在较高优秀率(50.9%)。与对照组预测假体型号之间的优秀率存在明显差异(P<0.05);而优良率之间差异无显著性意义(P>0.05)。当年龄≤65岁时,CT峡部测量法选择的假体型号优秀率可达63.9%;当峡部最长髓腔内径与最小髓腔内径的比值≥1.4时,CT峡部测量法的优秀率为70%。提示股骨假体在股骨峡部的紧密压配对股骨假体的稳定起重要作用。CT峡部测量法预测全髋关节置换股骨假体型号具有较高的准确性。

BACKGROUND：The template method used in cementless total hip arthroplasty is influenced by many factors,so the accuracy is poor.Studies demonstrated that femoral isthmus plays an important role in total hip arthroplasty,which affect femoral prosthesis.OBJECTIVE：To discuss the effects of femoral isthmus on cementless total hip arthroplasty.METHODS：The images of 4 cadaver femoral isthmus were obtained by computer tomography.The relations between femoral component and cortical bone contact were observed on coronal slices by sawing manully.The longest and the smallest medullary canal dimensions and the cortical thickness of femoral isthmus were measured by CT films from 50 patients（55 hips） prepared for primary total hip arthroplasty.The size of prosthesis was predicted based on the smallest medullary canal dimension of isthmus.And the conventional preoperative template was served as control.RESULTS AND CONCLUSION：There were a press fit and good contact between the femoral component and cortical bone of isthmus in 3 cadaver femoral bones.In 50 patients,the longest medullary canal dimensions of femoral isthmus were 8.2-22.4 mm（mean 14.2±3.1 mm）.The smallest medullary canal dimensions of femoral isthmus were 6.1-17.9 mm [mean（10.2±2.9） mm],and the cortical thickness of femoral isthmus were 2.7-12.7 mm [mean（7.5±1.8） mm].The results of CT-isthmus measurement method predicted sizes were excellence in the 50.9% cases.There was statistically significant difference of predicted sizes between the excellence rate of CT-isthmus measurement method and the rate of control（P 0.05）.Particularly,the excellence rate of CT-isthmus measurement method was 63.9% in the group aged below or equal to 65 years.When the ratio of the longest medullary canal dimensions and the smallest medullary canal dimensions of femoral isthmus was large than or equal to 1.4,the excellence rate of CT-isthmus measurement method was 70%.The press fit and good contact between the femoral component and femoral isthmus plays a very important role in stabilizing of femoral prosthesis in total hip arthroplasty.The predicted sizes of femoral prosthesis depending on the medullary canal dimensions of femoral isthmus measured by CT film has better accuracy than the conventional preoperative template.