@Cameleongirl - I too was told that the 1st replacement is the best. Subsequent ones aren't as good, as the 1st needs to be cut out and replaced. Bone is lost etc. I was told a younger person is 'generally' more active than say a very elderly person, might be walking more, shopping, working, commuting etc, therefore the replacement wears out quicker than someone older, that is less mobile. I was told in a younger person it might last 10 yrs, 15 if I was lucky. I'm early 40's, so therefore might need multiple replacements. My nan only recently died at 102 and another close relative at 104, so I don't think having 5+ replacements would be an option if I lived that long too!
OP- do you know if you have arthritis or what is causing you to need a replacement? I'm early 40's and have osteo arthritis, but mainly on the inner side of my knee. I will need a replacement in the future, but was advised to hold off as long as I can. Due to the pain being on the inner aspect, I finally found an off loader brace. It pushes the knee across, so the weight goes down the 'better' side of your knee. For me, it was a game changer!
Prior to finding this brace, I slept with a hot water bottle strapped to my knee, no analgesics worked, and I would literally be crying at night in pain- even when the leg was absolutely still.
The 1st brace style is more discreet and fits under clothes easily, but seemed to lose shape after a few months. The 2nd was more robust but cumbersome and something like the 2nd link. I can't find the exact one I had. I got both on the NHS, and needed to change them because I lost weight to try to help the pain.
thuasne-store.co.uk/product/action-reliever/
www.springloaded.com/knee-braces/top-five-offloader-knee-braces/
I realise that arthritis doesn't improve, but in my case, I needed to wear the brace to walk outside the house for over a year. I had physio and did exercises to strengthen the surrounding muscles. It meant I could return to work, shop and basically 'live' again, so to me, the brace was amazing. By some miracle, when I stopped physio, I was able to wean myself off the brace too! I do get the odd knee twinge now, but absolutely nothing like it was 2 yrs ago and I'm still brace and replacement free! If they have recommended a replacement, then a brace may not be suitable though for you.
My mum was hit by a car in her 30's and due to the damage, was advised that she would need hip/knee replacements at a younger than average age. She had a 1/2 knee done in her late 50's, a whole knee 60's and both hips in early 70's. She said that hips were better than knees in terms of recovery. She now needs the 1/2 knee re doing, but dances 3x a week, shops, drives, climbs 30 steps to get in/out of her front door.
She cannot squat or kneel, but hasn't been able to since being hit by the car. She doesn't run, but never has. Sorry this is so long 😬