Fig. 1

Schematic diagram of three-point positioning. a Intraoperative positive fluoroscopy, in which points A, B, and C are on or near a straight line. b During the operation, using lateral fluoroscopy positioning, the three points A, B, and C were in-line with the guiding needle. c The neck shaft angle was measured. d The angle between the posterior connecting line of the femoral condyle and the horizontal line was measured. e The angle between the femoral neck and the horizontal plane was measured. f In the lateral position, the A, B, and C are on a line