I would start with supported standing poses paying attention to how they stand and balance with support of a wall or countertop. Poses like utthita hasta padasana: legs spread apart ….feet accurately placed and arms extended in line with the shoulders. Or parsva hastasna learning to rotate the front foot and thigh with out losing their alignment. You could also begin with virabhadrasana 2 (warrior pose) with the hands on the wall or the waist. Do all the standing asanas against a wall for support. With a continuous practice of the asana the appendicular skeletal structure will improve. One learns the sense of movement and mobility within the poses bringing greater ease inside.