ObjectiveTo investigate the accuracy and value of digital planning with bone parameters in determining the appropriate prosthesis for total hip arthroplasty (THA). MethodsThe preoperative radiographs was taken in 13 cases scheduled for THA between September 2012 and June 2013; the bone parameters were measured by digital template, and the prosthesis was selected and preoperative plan was made. There were 4 males and 9 females with an average age of 54.08 years (range, 41-79 years), including 8 left hips and 5 right hips. The causes were osteonecrosis of the femoral head in 8 cases and femoral neck fracture in 5 cases (3 cases had osteonecrosis of the femoral head). ResultsThe operation time was 140-254 minutes (mean, 191.8 minutes). Two cases received blood transfusion, and 6 patients received plasma substitutes transfusion. There was no intraoperative fractures or postoperative thrombosis; atherosclerotic plaque occurred in 2 cases. Thirteen cases were followed up 12-24 months with an average of 17.3 months. The pain was relieved and limb function was improved in all patients. Harris score was significantly improved from preoperative 54.0±12.9 to 91.1±4.1 at 3 months after operation (t=7.259, P=0.000). Compared with the actual implants, the appropriate sizes of femoral stem was selected in 12 cases (92.31%) (excellent in 9 cases, good in 3 cases, and poor in 1 case), and the appropriate sizes of acetabular cup was selected in 11 cases (84.62%) (excellent in 7 cases, good in 4 cases, and poor in 2 cases). ConclusionDigital planning could increase the accuracy in choosing the size of prosthesis for THA.