abrasion below knee lead to psoriasis in that area.

I used to work in an environment where for a considerable amount of hours it was working low on the ground and so spent many hours in a day on a bended knee. In hind site I should of worn knee pads but at the time never had any reason to believe anything would come of it. Over time my knee grew quite red and slightly sore but never bled. About 3 years ago I woke to see a circular small patch similar or the same as plaque psoriasis covering just that area below the knee cap. It's almost a circle and the exact spot of skin that touches the surface of the ground when I bend my knee. The patch is thick and crusty but doesn't cause me to itch constantly and is no pain. If i pull at the crust it breaks and can bleed but doesn't just come away with mild scratching. I did a fair amount of research and used something called nixoderm which has been used for scaly skin in African countries. This above all other things tried actually clears the scales but they always come back. When applying Nixoderm it softens the scales to a point that you can just lightly pull away the hard plaques and they literally disintergrate and come away with no bleeding. When i first tried this i thought this was the miracle cure but unfortunately within 3 days or so the scales came back. Previously I had used an electric foot scrubber on the hard plaques to reduce the thickness and this greatly reduced the appearance but again is just a quick fix say if going on holiday but the nixoderm is better a it removed everything temporarily. I have seen a dermatologist who says that it is a case of plaque psoriasis. I was itching my anus possibly going back to about 4/5 years and still do. He says that I might have a case of genital posriasis which has affected the inner buttocks/anus area. I only ever find myself scratching this at night in bed possibly when it's warm and humid in that area but i don't realise i'm doing it as it's normally in my sleep. What i'd like to know and also have asked my doctor is if it's possible to have the area on the knee cut away since in my opinion I had no issues with posiraisis visible on the skin until I damaged the skin on knee through work. The Doctor advised that I can't go to a hospital to see a specialist for this if it a work related injury from sometime ago as he thinks its just posiasis and can be treated with steroid creams although probabaly won't ever completely clear. I don't mind paying for a private consultant to look and treat this if it can be cut away. I just wondered if others have had psoriasis in only one small specific area and if it was possible to remove just that area of skin completely below the plaque so as to possibly let it heal back as a scar.