Ranawat三角法对确定正常髋关节旋转中心的意义

摘要

背景:通过X射线片确定髋关节的旋转中心具有重要的临床意义,目前常使用Ranawat三角法来确定髋关节发育不良或关节置换后伴骨缺损病例的关节旋转中心,但此方法对确定正常髋关节旋转中心的意义研究较少.目的:探讨Ranawat 三角法和Mose圆法对确定发育正常的髋关节旋转中心的差异.方法:选择 30 例发育正常创伤性股骨颈骨折进行单侧全髋关节置换的患者,分别通过 Ranawat 三角法和Mose圆法对置换后骨盆正位X射线片进行测量,比较二者确定的髋关节旋转中心与参考线(X轴为两侧泪滴的连线,Y轴为通过Kohler线与X轴交点的垂线)的距离(Ranawat三角法确定的髋关节旋转中心与X轴的距离为dx1,与Y轴的距离为dy1,Mose圆法分别为dx2,dy2)及其占骨盆高度(两侧髂骨翼最高点连线和两侧坐骨结节最低点连线之间的距离)、宽度(两侧髂嵴最外缘间的距离)比例(dx1/H,dy1/W;dx2/H,dy2/W)的差异.结果与结论:Ranawat三角法dx1=(19.52±3.03) mm,dy1=(24.43±2.26) mm,Mose圆法dx2=(11.90±3.55) mm,dy2=(34.29±3.79) mm,二者之间差异有显著性意义(P＜0.001);其所占骨盆高度、宽度的百分比(dx1/H= 0.0992±0.0133,dy1/W=0.0855±0.0069;dx2/H=0.0611±0.0194,dy2/W=0.1201±0.0178),差异有显著性意义(P＜0.001).使用散点图对以上数据进行分析发现,Ranawat三角法所确定的髋关节旋转中心更靠近端和内侧,可能对关节周围的力学环境产生一定的影响.对于双侧髋关节发育不良及关节翻修的病例,由于髋臼周围结构的改变,使用Ranawat三角来确定髋关节的旋转中心不失为一种可行之法.而对于单侧病变的病例,以健侧为对照采用Mose圆法能更准确的确定髋关节旋转中心.%BACKGROUND:It is crucial to determine the location of the rotation center of the hip joint using X-ray.Ranawat's triangle is commonly used to define the hip rotational center in bilateral developmental dysplasia of the hip and revision hip surgery especialy in cases with bone stock deficiency,but there are rare articles about its value in normal hip.OBJECTIVE:To compare the difference between Ranawat's triangle method and Mose circle method in determining the healthy hip joint rotational center.METHODS: We selected 30 patients with normal traumatic femoral neck fracture,who underwent unilateral total hip arthroplasty.Ranawat's triangle method and Mose circle method were applied to measure the anteroposterior radiographs of the pelvis after arthroplasty and to compare the distance between the hip rotational center and the reference lines (X-axis: teardrop line; Y-axis: a line perpendicular to the X-axis,drawn from the intersection of theKohler line and the teardrop line.The distance from the hip joint rotational center to X-axis is dx1,dx2 and the distance to Y-axis is dy1,dy2 in Ranawat's triangle and Mose circle respectively.).We also compared the ratios (dx1/H,dy1/W; dx2/H,dy2/W) in the pelvic height (H: the distance between the highest point on the iliac wing and the lowest point on the ischial tuberosity) and width (W: the distance between the most lateral points on the iliac crests).RESULTS AND CONCLUSION:When the values were compared with both methods,highly significant differences were observed for both X and Y,Ranawat's triangle method dx1=(19.52±3.03) mm,dy1=(24.43±2.26) mm; and Mose circle method dx2=(11.90±3.55) mm,dy2=(34.29±3.79) mm (P＜0.001) and these ratios (dx1/H=0.0992±0.0133,dy1/W=0.0855±0.0069; dx2/H=0.0611±0.0194,dy2/W=0.1201±0.0178) in pelvic height and width (P＜ 0.001).Scatterplot results demonstrated that the hip rotational center identified by Ranawat's triangle method is near to the proximal end and medial end,which may affect mechanical environment surrounding the joint.For cases of bilateral hip dysplasia and joint revision,because of the changes in structure surrounding the acetabulum,Ranawat's triangle method can be a feasible method to identify the hip rotational center.For cases of unilateral lesion,Mose circle method can exactly identify the hip rotational center taking healthy side as a control.