Purpose: The purpose of this study was to evaluate the usefulness of our method, which estimated femoral stem alignment using a c-arm when the broach was inserted, for prevention of femoral stem malalignment.
Materials and Methods: A total of 103 hips were enrolled in this study. All patients underwentprimary hip arthroplasty from October 2011 to February 2013. The study was conductedretrospectively. Intraoperative estimated femoral stem alignments and final femoral stem alignments were classified into three groups. Multinomial logistic regression analysis was performed for analysis of factors (age, sex, diagnosis, body mass index, femoral stem size, osteoporosis, and proximal demur geometry) thatmight affect intraoperatively estimated femoral stem alignment.
Results: The distribution of intraoperative estimated femoral stem alignment was 80(78%) in the neutral group, 18(17%) in the varus group, and 5(5%) in the valgus group. The distribution of final femoral stem alignment was 100(97%) in the neutral group, 2(2%) in the varus group, and 1(1%) in the valgus group. There was no statistically significant factor affecting the intraoperatively estimated femoral stem alignment.
Conclusion: Intraoperative estimated femoral stem alignment using a c-arm is an effective method for prevention of femoral stem malalignment.

Keywords: Hip, Arthroplasty, Cemented femoral stem, Malalignment