What is The Fiqh of Praying Sitting Down?
I pray that you are in the best of health and faith, insha’Allah.
If it is painful to go fully into the bowing posture (ruku`), perform a minimal bowing which is simply to reach to your knees with your hands. If it is painful in the sitting (tashahud) posture, you may sit in any way that is comfortable (for example, cross-legged). If that is also very difficult, you may sit up on a stool or something similar for the final sitting (tashahud).