"Operation cancelled for a 3rd time"

It took 2 years for me to be told I would have a knee replacement after being told I needed it. They said I was too young.. In Sept 17. I put my back out and was unable to walk for 4 months. HR pestered me to redeploy from Oct 16. In Feb 18 my op was put off for 3mths for 1 day of snow, I finally came to AE with my back they sent me away telling me to exercise. I got a letter putting my knee off because my blood sugar was high. In April, my GP overlooked referring back to the hospital I waited 5mths  for my appointment that never came. In June-July 18 I saw physio in MPH because my back was still bad they gave me exercises that made me worse and made my head shake worse. I finally got a scan in Sept that told me I had two prolapsed disc. 

I came in finally to have my knee done in mid Oct 18. I was sat in Sals in my gown and it was cancelled again (3rd time). They have now given me mid Nov 18. and still I turn up home every work day with a backbrace for my back, a limp in my leg, with no consideration that I'm on my feel all day. I have loyalty to my work place and they have just treated me disgustingly