A few months ago a lady came to me with severe knee pain caused by advanced arthrosis.
Arthrosis is when the cartilage is worn away and bone rubs against bone. (Learn about Arthrosis here) Arthrosis is what caused her knees to bend inward.
She was afraid to have double knee surgery & continuously put it off. This caused the arthrosis to get worse to the point of immobility.
The last month before surgery she was wheelchair ridden. At this point the daughter had enough, & insisted her mother undergo the procedure.
As you can see, the knee surgery was a great success.