I have no meniscus left in my knee plus a deteriorating cartilage. Doctors tell me it’s to early for knee replacement as I am only 62 . I have worked as an irrigation technician for the last 20 years . Know I am unable to kneel down thus causing me to do a limited amount of work. Walking on uneven surfaces causes great pain in my knee. I use to work 45 hrs a week now I have difficulty working a few hours a day and there are things I can no longer do cause I am unable to kneel down. I am on cop which I took at 60 is there a disability top up which I am entitled to receive?