Weight-bearing 3D morphology of valgus knees: A comparative study within a varus dominant cohort

Using a weight-bearing 3D assessment method to characterize the skeletal morphology and lower-limb alignment of valgus knees, using a larger cohort of varus knees as a reference.

We retrospectively reviewed imaging data of Knee osteoarthritis (KOA) patients (2010-2025), including 60 valgus and 264 varus knees classified by the coronal hip-knee-ankle (HKA). CT-based 3D bone models were registered to biplanar weight-bearing radiographs to quantify femoral and tibial morphological parameters and lower-limb alignment under weight-bearing conditions.

Compared with varus knees, valgus knees had greater femoral neck anteversion and larger condylar twist angle (both p < 0.05). The location of maximum tibial bowing was more proximal in varus knees than in valgus knees (p = 0.039). Distal tibial articular surface inclination showed opposite directions (p = 0.027). Coronal alignment revealed higher medial proximal tibial angle (MPTA) and lower lateral distal femoral angle (LDFA) in valgus knees and opposite findings in varus knees, resulting in significantly different arithmetic hip-knee-ankle (aHKA) phenotypes between the two groups (all p < 0.001). Axial alignment differed significantly, with relative tibial internal rotation in varus knees and external rotation in valgus knees (p < 0.001). Sagittal knee extension did not differ between groups.

This study uses weight-bearing 3D assessment technology to investigate valgus knees within a dataset dominated by varus knees, comparing differences in skeletal morphology and lower-limb alignment between varus and valgus knees. These results indicate that, compared with varus knees, valgus knees exhibit demonstrate skeletal morphology and lower-limb alignment across multiple planes. These findings provide new evidence supporting multiplanar differences in the phenotypic characterization of knee osteoarthritis.

Level III.