Background During the last century, total hip arthroplasties have become more popular. They have had a huge impact on the quality of life, pain, range of motion, social interaction, and psychological well-being. A number of studies have emphasized the importance of using templates to choose the appropriate implant size when planning the surgery. Our aim is to use MediCad(R)software to analyze the ability of the digital template system MediCad(R)to predict the size of the implant needed in total hip arthroplasties. Materials and Methods An arthroplasty preoperative plan was created according to the MediCad(R)software guidelines, on anteroposterior hip X-ray by one junior resident, one senior resident, and three experienced hip surgeons. Results The median size accuracy was 0.7 (range: 0.27-0.87) for the cup, 0.73 (range: 0.36-0.83) for the stem, and 0.28 (range: -0.14-0.69) for the neck. Interobserver reliability was good (kappa > 0.4) and stronger when measuring the stem than when doing so with the cup. Conclusion: Digital preoperative total hip arthroplasty planning is a good method for predicting component size, restoring hip anatomy (vertical offset and horizontal offset), with good interobserver reliability.