What Does Stiffness In The Legs Indicate?

Have trouble lifting my leg more than a few inches off the ground - standing or sitting. It is not painful to sit but leg stiff after sitting any length of time. Occasionally, there is a shepsarp pain that causes my leg to buckle a little. Feel like I have more support if I press hand on top of thigh when walking or going up steps. I had xray of hip and there is mild bone on bone and some authritis