步态周期下胫距关节旋转轴变化的在体测量研究

In-vivo measurementof the geometric rotation axis of the talocrucial joint during normal gait

目的采用双平面透视技术结合三维-二维匹配方法评估胫距关节旋转轴的位置与方向的动态变化。方法使用两个垂直放置的"C"型臂X线机对15位健康受试者步态周期中7个关键时相的进行透视摄片,其中男7位,女8位;年龄(26.2±5.4)岁(范围19~39岁);身高(170.4±6.9)cm(范围160~183 cm);体重(65.6±14.0)kg(范围50~100 kg)。结合三维-二维匹配方法确定步态中的不同时相胫骨、距骨空间位置,分别对距骨滑车面内外侧进行球形拟合,其几何旋转轴定义为拟合球体的球心连线。分别计算内外侧拟合球体半径,并比较7个时相的6次空间变化旋转轴的空间位置与成角。结果双球拟合的内侧球半径为(19.52±1.47)mm,外侧半径为(20.62±1.49)mm,差异有统计学意义(t=7.081,P<0.05)。胫距关节几何旋转中心与原点的前后方向距离分别为(1.54±1.84)、(1.71±1.69)、(1.70±1.57)、(1.72±1.62)、(1.80±1.75)和(1.96±1.86)mm;内外侧方向距离分别为(0.06±1.84)、(-0.03±1.83)、(0.08±1.83)、(0.10±1.73)、(0.10±1.47)和(0.09±1.46)mm;上下方向距离分别为(-21.92±1.46)、(-22.10±1.32)、(-22.10±1.50)、(-22.06±1.64)、(-21.93±1.62)和(-21.98±1.50)mm;其几何旋转轴与冠状面成角分别为3.31°±2.48°、3.10°±2.67°、3.64°±2.71°、3.96°±3.19°、4.28°±2.82°、4.16°±3.11°;与矢状面成角分别为84.11°±2.42°、83.77°±3.19°、83.77°±3.45°、83.81°±3.69°、83.99°±2.97°、84.23°±3.01°;与水平面成角分别为4.40°±2.93°、4.54°±3.74°、3.97°±3.34°、3.73°±2.49°、3.78°±2.76°、4.48°±2.49°。各组间差异均无统计学意义(均P>0.05)。该旋转轴与水平面平均成角3.74°,与冠状面平均成角4.15°,从踝关节外下指向内上。结论胫距关节在步态周期下可能是沿着单一固定的旋转轴运动,使用拟合球体半径内侧小于外侧的单旋转轴的双球模型拟合距骨滑车面,可能更加符合胫距关节的运动学特点。

Objective To measure and compare the geometric rotation axis of the talocrucial joint at different poses during the normal gait.Methods The kinematic data of 15 healthy volunteers,8 females,7 males;age,26.2±5.4 y(range 19-39 y);height,170.4±6.9 cm(range 160-183 cm);mass,65.6±14.0 kg(range 52-100 kg).They were collected using the dual-fluoroscopy technique,and the spatial position of the tibia and talus was determined using the 3D-2D registration method.The medial and lateral side of the trochlear of each talus was fitted by two spheres and the geometric rotation axis of the tibiotalar joint was defined as the line connecting the origins of two spheres.Compared the position and orientation of the axis for different poses during the gait and also compared the difference of the radius of the medial and lateral spheres fitting the trochlear of each talus.Results The radii of the medial spheres fitting the trochlear of each talus 19.52±1.47 mm,were significantly less than that of the lateral spheres 20.62±1.49(t=7.081,P<0.05).The averaged anterior-posterior distance between the geometric rotation point of the tibiotalar joint were 1.54±1.84,1.71±1.69,1.70±1.57,1.72±1.62,1.80±1.75,1.96±1.86 mm,respectively,while the averaged medial-lateral distance were 0.06±1.84,-0.03±1.83,0.08±1.83,0.10±1.73,0.10±1.47,0.09±1.46 mm,respectively,and the averaged superior-inferiordistance were-21.92±1.46,-22.10±1.32,-22.10±1.50,-22.06±1.64,-21.93±1.62,-21.98±1.50 mm,respectively.The averaged angle between the geometric rotation axis of the tibiotalar joint and coronal plane were 3.31°±2.48°,3.10°±2.67°,3.64°±2.71°,3.96°±3.19°,4.28°±2.82°,4.16°±3.11°,respectively,while the averaged angle between that and sagittal plane were 84.11°±2.42°,83.77°±3.19°,83.77°±3.45°,83.81°±3.69°,83.99°±2.97°,84.23°±3.01°,respectively,and the averaged angle between that and transverse plane were 4.40°±2.93°,4.54°±3.74°,3.97°±3.34°,3.73°±2.49°,3.78°±2.76°,4.48°±2.49°,respectively.The position and orientation of the geometrical rotation axis of the tibiotalar joint at different poses during the gait showed no significant difference(P>0.05).The rotation axis orientated from laterally and inferiorly to medially and superiorly with an averaged inclination angle from the horizontal plane of 3.74°and an averaged deviation angle from the coronal plane of 4.15°.Conclusion The geometric rotation axis of the tibiotalar joint was fixed during the gait,therefore fitting the talar trochlea with the two-sphere model with a small radius of the medial sphere and a large radius of the lateral sphere may better mimic the kinematics of tibiotalar joint.