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Abstract
Purpose
The aim of this study was to establish a measurement standard for the weight-bearing axial alignment of the lower extremities when performing a lower extremity reconstruction.
Materials and Methods
Among 274 patients (147 males and 127 females) in their 20s to 30s without any physical disabilities, and who had undergone weight-bearing full leg standing radiographs, 188 patients (100 males and 88 females) were examined this study. The data was analyzed further according to their age and gender using the radiographic value on the coronal and sagittal alignment of the lower extremities.
Results
The weight bearing ratio was 38.47±10.52% on the coronal plane and 36.11±7.88% on the sagittal plane. Both the mechanical axis and the the weight bearing axis were not identical due to their 0.68±0.89° difference on average. The most adjacent point of the femoral condyles to the tibial plateau on the sagittal plane was assigned to the center of the knee joint. The difference between the mechanical axis and weight bearing axis was 0.04°, which was not significant.
Conclusion
There is a difference between the mechanical axis, which consists of both a line from the center of the femoral head to the center of knee joint and a line from the center of the knee joint to the center of ankle joint, and the weight bearing axis, which is linked directly from the center of the femoral head to the center of the ankle joint. Furthermore, the weight bearing axis passes through the anteromedial part in the knee joint. The center of the knee joint is defined as the most adjacent point of both femoral condyle to the tibial plateau on the sagittal plane.
Figures and Tables
Figure 1
Weight bearing full leg standing view. (A) About 1/2-1/3 of fibular head Overlaps with tibial condyle in anteroposterior view. (B) Lateral view. Both femoral condyles overlap each other. (C) Antero-posterior view position. Spreading legs as the width between both femoral head center and patella forward facing. (D) Lateral view position. One leg standing weight bearing position.
Figure 2
Knee joint center. (A) Points used to determine the center of the knee in coronal plane are shown. (B) Points used to determine the center of the knee in sagittal plane are shown.
Figure 3
Weight-bearing axis (A), femoral mechanical axis (B), tibial mechanical axis, (C), femoral anatomical axis (D) and tibial anatomical axis (E) are shown.
Figure 4
Weight-bearing ratio. (A) In coronal plane view, weight bearing ratio is (a/b)×100. (B) In sagittal plane view, femur weight bearing ratio is {a/(a+b)}×100, and tibia weight bearing ratio is {c/(c+d)}×100.
Figure 5
Various angles in coronal plane view are shown. (A) femoro-tibial anatomical angle, (B) angle of femoral anatomical axis-weight bearing axis, (C) angle of tibial anatomical axis-weight bearing axis, angle, (D) angle of femoral mechanical axis-weight bearing axis, (E) angle of tibial mechanical axis-weight bearing axis, (F) femoral bowing angle, (G) tibial bowing angle.
Figure 6
Various angles in coronal plane view are shown. (A) femoro-tibial anatomical angle, (B) angle of femoral mechanical axis-weight bearing axis, (C) angle of tibial mechanical axis-weight bearing axis, (D) distal femoral anterior angle, (E) femoral bowing angle, (F) tibial bowing angle.
Figure 7
On sagittal plane view, tibial posterior slope angle for weight bearing axis (α), for anterior tibial cortex (β), for fibular shaft (γ), and for tibial anatomical axis (δ) are drawn.
Figure 8
Diagram showing the point on the tibial plateau through which the weight bearing axis passes.
Table 1
Total Radiologic Results of Coronal and Sagittal Measurement
WBR, weight beraing ratio; FTA, femoro tibial angle; FAA, femoral anatomical axis; WBA, weight beraing axis; TAA, tibial anatomical axis; FMA, femoral mechanical axis; TMA, tibial mechanical axis; FL, femoral length; TL, tibial length; FBA, femoral bowing angle; TBA, tibial bowing angle; DFA, distal femoral angle; TPS, tibial posterior slope; ATC, anterior tibial cortex; FSA, fibular shaft angle.
Table 2
Comparison of Radiologic Results between Third Decade and Fourth Decade
FTA, femoro tibial angle; WBR, weight beraing ratio; FAA, femoral anatomi cal axis; WBA, weight beraing axis; TAA, tibial anatomical axis; FMA, femoral mechanical axis; TMA, tibial mechanical axis; FL, femoral length, TL, tibial length; FBA, femoral bowing angle; TBA, tibial bowing angle; FWBR, femoral weight bearing ratio; TWBR, tibial weight bearing ratio; DFA, distal femoral angle; TPS, tibial posterior slope; ATC, anterior tibial cortex; FSA, fibular shaft angle.
Table 3
Comparison of Radiologic Results between Male and Female
WBR, weight bearing ratio; FTA, femoro tibial angle; FAA, femoral anatomical axis; WBA, weight bearin axis; TAA, tibial anatomical axis; FMA, femoral mechanical axis; TMA, tibial mechanical axis; FL, femoral length, TL, tibial length; FBA, femoral bowing angle; TBA, tibial bowing angle; FWBR, femoral weight bearing ratio; TWBR, tibial weight bearing ratio; DFA, distal femoral angle; TPS, tibial posterior slope; ATC, anterior tibial cortex; FSA, fibular shaft anlge.
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