In-vivo measurementof the geometric rotation axis of the talocrucial joint during normal gait / 中华骨科杂志

ABSTRACT

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.