Is Knee Replacement Surgery Advisable For Severe Pain And Stiffness In Knee?

Am I ready for a knee replacement or can I get by with another steroid injection? Getting up from the toilet is getting more difficult. Going downstairs I must go one step at a time. I can not bend my leg back without much discomfort. Sometimes once I am up and going it does not bother me too much. Two years ago I was told I had bone on bone but only on one side of my knee. Can I have a half knee?