Computer assistance in prosthetic hip surgery is able to improve the accuracy of the surgery: Associating hip navigation and EOSTM imaging pre-operatively could simplify the procedure of hip navigation in lateral decubitus while maintaining the accuracy of the technique

Hip navigation based on preoperative EOS(TM) imaging could help to improve the accuracy of cup positioning like other computer assisted hip surgery, but it would also simplify the procedure in lateral decubitus. Indeed, the registration of the controlateral antero superior iliac spine and the pubis is not necessary with this technique. The target population of the study is the one affected with primitive hip osteoarthritis for which an indication of prosthesis of total hip has been chosen Expected Result: Simplification of the procedure of navigation of the cup. Decrease in the number of cups positioned out of the "security zone" compared to the standard manual technique of cup positioning. A result of 50% of good positioning is expected with the manual technique versus 80% with the technique of navigation based on EOS(TM).

MAIN OBJECTIVE: Compare the surgical treatment of total hip prosthesis without assistance by computer and total hip prosthesis with navigation based on imaging EOSTM pre-operative Comparative clinical trial of superiority, randomized in single blind, in 2 parallel groups: -Group 1: Installation of hip prosthesis without assistance by computer -Group 2: Installation of hip prosthesis with assistance by computer based on imaging EOS(TM)

Inclusion Criteria:

• Nosologic criteria :
• Primitive clinic hip osteoarthrosis
• secondary secondary clinic hip osteoarthrosis : osteonecrosis of femoral head posttraumatic
• Primitive radiological hip osteoarthrosis,
• Indication of total hip prosthesis
• Free informed and written consent, dated and signed by the patient and the investigator before any examination required by the research
• Subject affiliated or beneficiary of the social security
• Man or woman aged from 40 to 90 years

Exclusion Criteria:

• The navigation based on EOSTM imaging. requires the visualization on the EOSTM. pre-operative radiography of 6 radiological bone markers. The non-viewing of these markers is a criterion for exclusion of the study.
• anaesthetic contraindication
• pregnant women
• Persons under the control of justice