全髋关节置换前假体型号的选择方法

背景：假体和股骨近段髓腔横断面的匹配非常重要,模板测量法术前预测股骨假体型号准确率低,因此有必要寻找新的方法用于全髋关节置换前预测假体型号。目的：利用CT测量股骨峡部最小髓腔内径及股骨颈髓腔内侧径,并通过两种髓腔径大小术前选择股骨假体型号。方法：利用CT测量52例61髋初次全髋关节置换患者置换前股骨颈髓腔内侧径和峡部最小髓腔内径大小,根据两种髓腔的大小进行术前选择股骨假体型号;以常规模板测量法作为对照。分析两种方法术前选择股骨假体型号的可行性、准确性。结果与结论：股骨颈髓腔内侧径和峡部最小髓腔内径大小与股骨假体型号之间都存在很强的相关性（r=0.97-0.99,P〈0.05）。CT峡部测量法术前选择股骨假体型号的优秀率为47.5%;比模板测量法有更好准确性,尤其是在≤65岁的年龄段。股骨颈内侧径测量法置换前选择股骨假体型号优秀率为52.5%;比模板测量法有更好准确性,尤其在〉45岁的年龄段。CT峡部测量法对于年龄≤65岁或股骨干髓腔窄小者有较好临床应用价值。股骨颈内侧径测量法则在年龄〉45岁或股骨干髓腔宽大者的置换前选择假体型号方面具有更好的准确性。两种方法综合运用有利于选择出匹配度更高的股骨假体。

Selection of prosthesis size before total hip arthroplasty

BACKGROUND：A good press-fit between the femoral component and the cross-section of medullary cavity of proximal femur is very important.The accuracy of preoperative measurement of prosthesis model by template measurement method was low.It was necessary to search a new method for preoperative prediction of prosthesis model.OBJECTIVE：To measure the minimum medial dimension of medullary cavity of femoral neck and the intramedullary dimension of femoral isthmus by CT in order to predict the size of suitable femoral prosthesis in total hip arthroplasty.METHODS：Clinical data of 52 patients（61 hips） undergoing primary total hip arthroplasty were collected.The size of the femoral stem was accurately measured from preoperative CT film based on the medial dimension of medullary cavity of femoral neck and the intramedullary dimension of femoral isthmus.Conventional preoperative template measurement method was served as control.The feasibility and accuracy of the two methods to predict the size of the prosthesis was analyzed.RESULTS AND CONCLUSION：The medial dimension of medullary cavity of femoral neck and the intramedullary dimension of femoral isthmus were correlated fairly well with sizes of the stems（r=0.97-0.99,P 0.05）.There were 47.5% cases of CT-isthmus measurement method predicted sizes were excellence,and the accuracy of the CT-isthmus measurement method was better than that of the template measurement method,especially in the age below or equal to 65 years.The results of the medial-dimension measurement method of femoral neck predicted sizes were excellent in 52.5%,and the accuracy of the medial-dimension measurement method was better than that of the template measurement method,especially in the age more than 45 years.CT-isthmus measurement method has better clinical value in the patients with the age below or equal to 65 years or in the patients with narrow medullary cavity of the femoral stem,while the medial-dimension measurement method of femoral neck has better accuracy in the prediction of the prosthesis model preoperatively in the patients with the age more than 45 years or in the patients with large medullary cavity of the femoral stem.It suggested that the application of the two methods was feasible for prediction of femoral component in total hip arthroplasty.