Knee pain and numbness

My (42f) right knee has taken some damage over the years (was hit by a car whole riding my bike, and had a large stone sculpture overextend it), and despite that my knee seemed mostly gine, but over the last year or so I started to have increasing pain on the right side of my right knee, the pain has escalated significantly in the last few months, to the point i cannot kneel on that knee without a sharp tearing sensation that lingers after I get up. The skin around the pain is mostly numb to the touch. i have an ortho appointment, but i wonder if anyone has any idea what's going on?