Tibia‐only planning to 3° valgus implies mechanical medial proximal tibial angle ≥94° in about two‐thirds of varus knee osteoarthritis radiographs
5 affiliations
- 1Department of Orthopaedic Surgery, Shanghai Key Laboratory of Orthopaedic Implants, Shanghai Ninth People's Hospital Shanghai Jiao Tong University School of Medicine Zhizaoju Road Shanghai China
- 2Yingwei Medical Technology (Shanghai) Co. Ltd. Shanghai China
- 3Department of Radiology, Shanghai Ninth People's Hospital Shanghai Jiao Tong University School of Medicine Shanghai China
- 4Institute of Image Communication and Network Engineering Shanghai Jiao Tong University Shanghai China
- 5Shanghai Key Laboratory of Digital Media Processing and Transmission Shanghai China
Abstract
Purpose: To estimate the proportion of radiographic records from patients with varus knee osteoarthritis in which tibia‐only planning targeting a hip–knee–ankle angle (HKA) of 183° (3° valgus) yielded a calculated mechanical medial proximal tibial angle (mMPTA) of at least 94°.
Methods: In a retrospective database, 1426 knee‐specific records were screened. Eligible records came from adults with standardised standing full‐length lower‐limb radiographs. Exclusions covered hip and foot deformities, spontaneous femoral condyle osteonecrosis, previous lower‐limb surgery, malignancy, major trauma, poor image quality and excessive rotation. Symptomatic knee osteoarthritis, numerical quality control and HKA below 176.5° defined the analytical cohort. Alignment was measured using an artificial intelligence‐assisted system. Correction was assigned entirely to the tibia. The mechanical lateral distal femoral angle and joint line convergence angle were held constant. The primary target was 3° valgus; 1°, 2°, 4°, 5° and 6° of valgus were supplementary targets. Analyses were descriptive, with two‐sided 95% Wilson confidence intervals for proportions.
Results: The analysis included 627 records from 392 patients (mean age, 67.3 ± 9.2 years; 28.6% men). At the 3° valgus target, the mean calculated mMPTA was 96.0 ± 3.7°; 424/627 records reached at least 94° (67.6%; 95% confidence interval, 63.9%–71.2%). The most frequent deformity‐source patterns were intraarticular alone (24.7%) and tibial‐side plus intraarticular (24.4%).
Conclusions: At a 3° valgus target, tibia‐only planning implied an mMPTA of at least 94° in about two‐thirds (67.6%) of records from this varus knee osteoarthritis cohort. Preoperative planning should therefore assess local tibial joint‐line orientation and deformity source alongside the whole‐limb alignment target.
Level of Evidence: Level IV, retrospective radiographic geometry study.
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BibTeX
@article{jiang2026tibiaonly,
title = {{Tibia‐only planning to 3° valgus implies mechanical medial proximal tibial angle ≥94° in about two‐thirds of varus knee osteoarthritis radiographs}},
author = {Xu Jiang and Yicang Wang and Xing Li and Songtao Ai and Jun Zhou and Kai Xie and Liao Wang and Mengning Yan},
journal = {Journal of Experimental Orthopaedics},
year = {2026},
month = nov,
doi = {10.1002/jeo2.70977},
url = {https://doi.org/10.1002/jeo2.70977},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Tibia‐only planning to 3° valgus implies mechanical medial proximal tibial angle ≥94° in about two‐thirds of varus knee osteoarthritis radiographs
AU - Xu Jiang
AU - Yicang Wang
AU - Xing Li
AU - Songtao Ai
AU - Jun Zhou
AU - Kai Xie
AU - Liao Wang
AU - Mengning Yan
PY - 2026
DA - 2026/11/04
JO - Journal of Experimental Orthopaedics
DO - 10.1002/jeo2.70977
UR - https://doi.org/10.1002/jeo2.70977
AB - Purpose: To estimate the proportion of radiographic records from patients with varus knee osteoarthritis in which tibia‐only planning targeting a hip–knee–ankle angle (HKA) of 183° (3° valgus) yielded a calculated mechanical medial proximal tibial angle (mMPTA) of at least 94°. Methods: In a retrospective database, 1426 knee‐specific records were screened. Eligible records came from adults with standardised standing full‐length lower‐limb radiographs. Exclusions covered hip and foot deformities, spontaneous femoral condyle osteonecrosis, previous lower‐limb surgery, malignancy, major trauma, poor image quality and excessive rotation. Symptomatic knee osteoarthritis, numerical quality control and HKA below 176.5° defined the analytical cohort. Alignment was measured using an artificial intelligence‐assisted system. Correction was assigned entirely to the tibia. The mechanical lateral distal femoral angle and joint line convergence angle were held constant. The primary target was 3° valgus; 1°, 2°, 4°, 5° and 6° of valgus were supplementary targets. Analyses were descriptive, with two‐sided 95% Wilson confidence intervals for proportions. Results: The analysis included 627 records from 392 patients (mean age, 67.3 ± 9.2 years; 28.6% men). At the 3° valgus target, the mean calculated mMPTA was 96.0 ± 3.7°; 424/627 records reached at least 94° (67.6%; 95% confidence interval, 63.9%–71.2%). The most frequent deformity‐source patterns were intraarticular alone (24.7%) and tibial‐side plus intraarticular (24.4%). Conclusions: At a 3° valgus target, tibia‐only planning implied an mMPTA of at least 94° in about two‐thirds (67.6%) of records from this varus knee osteoarthritis cohort. Preoperative planning should therefore assess local tibial joint‐line orientation and deformity source alongside the whole‐limb alignment target. Level of Evidence: Level IV, retrospective radiographic geometry study.
SN - 2197-1153
ER -