The varus cemented femoral stem in total hip arthroplasty: Predictors, implications and The Femoral Access Ratio

Introduction: We describe a novel morphological ratio, the Femoral Access Ratio, in the preoperative femur to investigate the predictors of femoral stem malalignment.Methods: We reviewed 70 cemented femoral stems. Preoperative 'FAR' score was measured. Postoperative coronal stem alignment was measured and ten year survivorship and functional outcomes investigated.Results: There were three predictors of varus stem malalignment-BMI, GT-height and 'FAR' score. Increasing BMI led to higher rates of malalignment (p = 0.048). 'FAR' score <1 lead to 68.4% of varus stems. GT height contributed most to the prediction of varus stem malalignment (p = 0.013).Conclusion: FAR score is a simple preoperative radiographic measurement that can predict the likelihood of femoral stem varus malalignment in cemented femoral stems.