籽骨移位与踇外翻关系的负重轴位X线研究

Axial Weight-Bearing X-ray Study on the Relationship between Sesamoid Transposition and Hallux Valgus

目的基于籽骨负重轴位片对第一跖骨头下胫、腓侧籽骨位置变化与踇外翻关系的研究。方法踇外翻49足均摄取足负重正位片及籽骨轴位片,依据正位片所测踇外翻角(HVA)分轻、中、重3组。在籽骨轴位片测量并获得胫、腓骨籽骨中心到第2跖骨长轴的垂直距离(SAPt-2、SAPf-2)及胫-腓籽骨中心距离(SAPt-f)来反映胫、腓侧籽骨的位置,为矫正各足解剖差异,将获得的距离值与第2跖骨长度(AB)的比值(SAPt-2/AB,SAPf-2,SAPt-f/AB)作为距离指标纳入统计分析。采用Pearson相关分析评价各距离指标与HVA、籽骨旋转角(SRA)的相关性,单因素分差分析用于进一步评价距离指标在踇外翻组间的差异有无统计学意义。结果腓侧籽骨位置(SAPf-2)与HVA、SRA均无明显相关性(P>0.05),胫-腓籽骨间距(SAPt-f/AB)与HVA呈负、弱相关(r=-0.305,P=0.033)、与SRA没有明显相关性(P>0.05),且两者在踇外翻组间差异均无统计学意义(P>0.05);胫侧籽骨位置(SAPt-2/AB)与HVA、SRA均呈中-低度负相关(r=-0.485、-0.518,P=0.000),其位置受踇外翻严重程度的影响,且在踇外翻组间差异有统计学意义(P=0.005<0.05)。结论籽骨负重轴位片可更好地反映运动状态下前足紊乱时第一跖籽关节的位置异常改变,运动状态下、随踇外翻加重时,腓侧籽骨位置没有发生改变,胫-腓籽骨间距维持不变,而胫侧籽骨随踇外翻加重朝向腓侧移动,由此可推测胫侧籽骨以腓侧籽骨中心为圆心、以胫-腓籽骨间距为半径以圆周运动的形式朝向腓侧移动。

Objective Under the condition of increased forefoot weight bearing,the X-ray sesamoid axial radiographs were used to investigate the relationship between the position changes of the tibial and fibular sesamoids under the first metatarsal bone and hallux valgus.Methods All 49 hallux valgus feet underwent foot weight-bearing anteroposterior and sesamoid axial radiographs,according to the hallux valgus angle(HVA)measured by anteroposterior radiograph divided into three groups:light,medium and heavy.In order to evaluate the tibial and fibular sesamoid bones position change,the distance from the tibial and fibula sesamoids to the second metatarsal(SAPt-2,SAPf-2)and distance between the tibial and fibula sesamoids(SAPt-f)were measured on the sesamoid axial radiograph.To correct the anatomical differences of each foot,the ratio of the obtained spacing value to the length of the second metatarsal(AB)(SAPt-2/AB,SAPf-2,SAPt-f/AB)was included in the statistical analysis.Pearson correlation analysis was used to evaluate the correlation between the distance indicator and HVA and SRA,then the differences of indexes between hallux valgus groups were evaluated by the method of one-way ANOVA.Results There was no significant correlation between SAPf-2 and HVA and SRA(P>0.05),SAPt-f/AB was negatively and weakly correlated with HVA(r=-0.305,P=0.033),and had no significant correlation with SRA(P>0.05),and both SAPf-2/AB and SAPt-f/AB were showed no statistically significant difference between hallux valgus groups(P>0.05).SAPt-2/AB showed statistically significant difference between hallux valgus groups(P=0.005<0.05),medium-low and negatively correlated with HVA and SRA(r=-0.485,-0.518,P=0.000).Conclusions Axial radiographs of sesamoid bone can better reflect the abnormal position of the first metatarsal-sesamoids joint when the forefoot is dislocated in motion.In the state of motion,with hallux valgus aggravating,the position of the fibular sesamoid bone did not change,and the tibia-fibular sesamoid bone spacing remained unchanged,but the tibial sesamoid moved towards the fibula.Therefore,the tibial sesamoid bone rotates outward with the center of the fibula sesamoid bone as the center of the circle and the tibia-fibular sesamoid spacing as the radius was obtained.