Knee arthritis from deep knee bends in hs. are they still doing those?

Maybe: Squats are hard on the knees but do not necessarily cause arthritis. Many people still do lunges and squats for exercise.

Closed chain ex: I do not understand by "hs". I always prefer leg press with differnt amount of resistance and required knee flexion depending upon degree of patellofemoral involvement. I rarely advised for any type of open chained exercises for knee.