It might be due to ankle pain
. Our suggestion would be to do hot water fermentation along with Cold (ice) therapy. You shall also keep a pillow under the knee while sleeping, next is you can keep ice in the painful area for about 5--10 minutes. If your pain is more in the distal joints, ie. In the upper limbs if the pain is present in the fingers/wrist and in the lower limbs it the pain is present in the toes/ ankle, then we shall definitely say it is Rheumatic arthritis
. Wear elbow brace
and wrist brace which will make her to feel warm and that will make the joints become firm. Hot water fermentation will help
Knee cap will also help to prevent the damaged cartilages.