I have allergies to 5 metals, but not to titanium which is the metal used. The surgeon told me even pure titanium is not pure. With use it will slough the titanium metal, including the trace amounts of other metals. I am not allergic to polyethylene or the bone cement. My fear is if I reject the implant, which many do, there won't be a replacement for the knee joint. What then a wheel chair?
There are ceramic coated implants. I was scheduled for this surgery 3 years ago. However I did my research and the implant he was going to put in a had class action lawsuit pending because the bone cement wasn't adhering to the coating. Also just like with metal, he told me the coating over the metal sloughs over time. This failure on part of the bone cement was reportedly being resolved, but I want to wait until they've proved it to be successful. You have brought up a good point though, at age 75 how many years would it take for the titanium metal to start sloughing?

You're right about PRP proving more successful with muscle, tendon and ligament. I was diagnosed with Chondromalacia Patella, CP, in my 30's, defiantly aggravated by my life style. I was part of the high impact aerobic generation. For example we would do 1,000 but squats as part of an hour work out session. Now in the last 6 months, at age 75 I'm having a hard time getting off the floor. Lesson learned..........
I can't change the way my knee cap rotates because of CP, but this grinding causes deterioration of the cartilage for which the PRP may help rebuild.
I may have waited too long. The doctor was going to do PRP last summer, but I wasn't willing to take a break from my active lifestyle and could still walk normally. I was told you need to be sedentary for 2 months afterwards, so I tolerated the pain. Now the pain can't be ignored, even Aleve does nothing, and my mobility is severely limited, one leg I have to drag or walk stiff legged on bad days.
I'm not ready to take up quilting.