It's important to figure out what's not important. Some excellent advice on that theme appears in The Yoga Year by Celia Toler (p. 242):

This twist warms the hips and prepares for full lotus, lengthening the thigh muscles and bringing the knee to the center. Since it is better to have good knees and no lotus, if you feel strain in the knee, perform the pose as in ...

A similarly sound suggestion is offered in Lunchtime Enlightenment by Pragito Dove (p. 13):

... For the sitting meditations, never force a posture. If you're not comfortable, any practice will simply create more tension and nothing will be achieved. If you can sit, good, but if it is a strain, try some other positions. If you cannot sit on the ground, then sit on a chair. Meditation is not afraid of chairs.

^z - 2010-10-15