• Neck-shaft angle ≤ 127.6° and greater trochanter-diaphysis offset ratio > 0.52 are independent risk factors for coronal varus positioning of cementless femoral stems in total hip arthroplasty.
• The combined prediction model using neck-shaft angle and greater trochanter-diaphysis offset ratio achieves superior predictive efficacy (AUC = 0.772) compared to single parameters.
• Preoperative measurement of these anatomical parameters can guide prosthesis selection and surgical strategy to reduce the risk of varus stem placement.
• The study introduces a novel parameter, greater trochanter-diaphysis offset ratio, expanding the assessment of proximal femoral morphology.