Related Experiment Video
Updated: Jul 12, 2026
The Lower Body Positive Pressure Treadmill for Knee Osteoarthritis Rehabilitation
Published on: July 22, 2019
Patients with knee osteoarthritis exhibit an abnormal three-dimensional lower limb phenotype: An EOS imaging study
Bo Wang1, Yubo Liu1, Dengfa Gao2
1School of Medicine, Nankai University, Tianjin 300071, PR China; Senior Department of Orthopedics, the Fourth Medical Center of PLA General Hospital, Beijing 100048, PR China; National Clinical Research Center for Orthopedics, Sports Medicine & Rehabilitation, Beijing 100853, PR China.
Objective:
To characterize the weight-bearing three-dimensional (3D) lower-limb phenotype associated with knee osteoarthritis (KOA) and assess whether noncoronal measurements provide information beyond conventional coronal alignment.
Design:
This retrospective cohort study used weight-bearing EOS images from a single-center database. Participants were classified by clinical diagnosis and radiographic assessment. Exact sex matching plus 1:1 nearest-neighbor propensity score matching for age and BMI (logit-scale caliper=0.10) generated 279 KOA-control pairs (n=558). Seventeen pelvic and lower-limb 3D parameters were quantified. Between-group differences were estimated using linear regression with matched-pair clustered robust standard errors and false discovery rate adjustment.
Results:
After FDR adjustment, 9 out of 17 parameters differed. Compared with controls, patients with KOA had greater varus alignment (HKA β=-3.72°; 95% CI, -4.50 to -2.94), increased LDFA and HKS, decreased MPTA, greater femoral offset and neck length, and a reduced neck-shaft angle. KOA also revealed greater sagittal flexion (β=6.74°; 95% CI, 5.58-7.90) and internal femorotibial rotation (β=-2.95°; 95% CI, -4.43 to -1.47). In exploratory models, adding sagittal parameters to a demographic/coronal model increased the optimism-corrected AUC from 0.691 to 0.776.
Conclusions:
Together, these findings reveal a focused multiplanar, weight-bearing lower-limb phenotype in KOA patients, indicating that clinical and research phenotyping should move beyond coronal alignment alone and provide a structural framework for future biomechanical and longitudinal studies.
