My husband is a yogi. He was of the Jain religion. He now practices his own meditation. I had asked him about sitting in the lotus position and why the yogi's all sat that way to meditate. I can't sit in a lotus position either due to arthritis in my hip and now in a recently operated on knee.
He said the reason why the lotus position was so popular was that Indian people are very poor and never had furniture so most of the people always sat on the floor, hence the lotus position evolving. He said when you are raised from a child in India, sitting on the floor, your back becomes much stronger and the Indian people are more used to sitting that way than westerners. It's natural for them.
So now, I for one, don't believe that if you can't sit in lotus position, you won't become enlightened or experience total freedom.
It's your mind that frees you, not how you sit.