[Preoperative planning interest of a total hip prosthesis].

Total hip arthroplasty (THA) is the standard surgical procedure for the treatment of severe hip osteoarthritis. THA can be subject to surgical and medical complications. One of the main expectations of our patients is to be able to resume all their daily activities. Preoperative planning of a THA is an essential step in the procedure. The reference method remains the 2D technique using «templates» positioned on an anteroposterior digital radiograph of the pelvis. It can also be done in 3D. In addition to the type and size of prosthetic components (cup, stem and prosthetic head), the planning allows the surgeon to restore the function through correction of any limb length and/or offset discrepancy, and soft tissue tensioning in order to reach the objectives set and to limit the risks of complications. In the opposite case, the surgeon exposes the patient to complications during or after surgery with probable negative consequences on the functional result. The positioning of the acetabular and femoral components is an important factor influencing the short- and long-term survival of THA. All patients undergoing total hip arthroplasty should have rigorous preoperative planning.