The objective of this study is to assess the changes in daily physical activity and gait pattern, following a viscosupplement injection among a population who is suffering from hip osteoarthritis. A kinetic and kinematic gait analysis, an Actigraph activity monitor, a functional Timed-Stair-Test and two questionnaires (Medical Outcome Study Short-Form36 (MOS-SF36), Hip disability and Osteoarthritis Outcome Score (HOOS)) about how the pathology affects the quality of life, will be use.

Inclusion Criteria:

• From 45 years old to 65 years old
• Clinically symptomatic moderate or severe hip osteoarthritis (Tönnis Grade II to III)
• Capacity to keep steady upright position and walking during 15 minutes
• Body mass index < 40kg/m2

Exclusion Criteria:

• Bilateral hip osteoarthritis
• No broken hip or leg during the last 12 months
• Bone necrosis
• Rheumatoid arthritis, articular chondrocalcinosis, metabolic bone disease, psoriasis, gout, active infection
• Per os corticosteroid treatment
• Corticosteroid injection < 3 months
• Viscosupplement injection < 6 months
• Hypersensitivity to hyaluronic acid products
• Planed surgery during study duration
• Physical or mental disability to fill in questionnaires and/or to participate to follow-up