Adamantine posture or Vajrasana where you sit on your heels is ideal to practice after having had a big meal, or to hold your body steady as you meditate. It is one that confers many benefits : better digestion if practised after a meal, stable support for the spine, helpful to strengthen the knees and ankles.
Although, if your knees are already busted it is best to avoid this one.
Some cool variations are the lying down version- supta vajrasana ( you may wish to try this lying on a bolster first) which is excellent for the quadriceps, or the forward fold – balasana.
Be where you are. Gather your thoughts.
Interesting trivia: Japanese culture and zen meditation, the Islamic prayer namaz also have versions of this pose prominently included in everyday practice.
Variations placing a block under where you sit or place a wedge in the crease of your knees so that they are most comfortat
If your knees are already in pain this posture is not suitable.