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Abstract
[1],[2],[3] Valgus deformity can exist during knee flexion besides extension, which could lead to patellofemoral joint instability and soft tissue imbalance in the flexion gap, and thus complicate the surgical procedures. [4] It usually results from a bone defect in the posterior part of the lateral femoral condyle (measured on CT scan) or valgus deformity in the tibia (measured on long-film radiograph). Radiographic analysis For every valgus knee, we measured the anatomical medial proximal tibial angle (aMPTA) on the long-film radiograph to detect valgus deformity in tibia [Figure 1]b. We then measured the posterior condylar angle (PCA) on CT scans to detect valgus deformity during 90 knee flexion resulting from a bone defect in the posterior part of the lateral femoral condyle [Figure 1]c. Valgus deformity in tibia exists throughout the full range of motion, which contributes to the valgus deformity during knee flexion. [...]an enlarged PCA is a sign of a bone defect in the posterior part of the lateral femoral condyle, which contributes to valgus deformity during only knee flexion but not an extension. The valgus deformity in the tibia and that resulting from a bone defect in the posterior part of the lateral femoral condyle contribute to the whole valgus deformity during knee flexion. [...]we can calculate the whole valgus angle during flexion. [...]we defined a whole valgus deformity < 3 as a negative finding, while a whole valgus deformity >3 as a positive finding. In these cases, the lateral collateral ligaments (LCL) are usually in contracture...