Adults suffer from Osteoarthrosis of hip joint that willing to participate in the study will be tested with well-established measuring techniques of Balance control using force plate before 3 month and 6 month after Total Knee Arthroplasty (THA) in the movement and Rehabilitation Laboratory at BGU. An automated algorithm will be used to extract standardized stabilogram-diffusion parameters from each of the COP data sets collected during quiet standing. These parameters include diffusion coefficients, critical displacement, critical time and scaling exponents for both lateral and anterior-posterior sway directions (Collins & De Luca, 1993). Each of the Times (before 3 month and 6 month after the THA) in two task conditions (eyes closed and eyes close conditions). Participants will be required to stand on the platform 10 times for 30 s For each trial, they will be instructed to sway as little as possible. In addition step execution test and Late life function and disability questionnaires will be also examined.

Inclusion Criteria:

• Able to stand safely for 30 seconds
• Able to walk independently
• Hip OA prior THA

Exclusion Criteria:

• Stroke or other neurological diseases
• Minimal score 24 or higher
• Blindness

30 adults suffer from Hip OA prior THA