Age
I was 59 when I had my first knee replacement and 72 when I had the last one.
I don't think my age made any difference at all to my recoveries.
The knee itself takes just a long to heal fully whether you're 18 or 80. That's something that younger, active people often find hard to accept and I think they experience more frustration because their recovery is taking longer than they expected it to.
My mother had two knee replacements, one at 75 and one at 82. She made a good recovery from both surgeries and was walking without help after about a month.
Mobility
Pre-op mobility does have a bearing on recovery. I waited 9 long, painful years before my first knee replacement. During that time, my mobility gradually decreased until I was almost house bound. That resulted in loss of muscle strength and some deformation of my tendons and ligaments.
Consequently, my recovery was impeded, because those soft tissues had a lot more recovering to do.
However, I did regain full mobility and went on to live a very active life.
I needed a revision 11 years later. I went into that with muscles and tendons in good condition and, even though revisions can often be harder, I found my recovery was a little easier than my original recovery.
I learned from my first mistake, and had my other knee revised as soon as my surgeon said it was ready. That recovery was relatively easy.
I don't think you can assume that people who still need crutches or sticks at 6-8 weeks post-op do so because they haven't done their exercises. It's far more likely to be because of the condition of their knee and their general health before the surgery. Every knee is different. There's no way that you could know either the state of their knees before surgery, or the extent of surgery that they needed.
I've had 3 knee replacements, 3 good recoveries, and 2 different surgeons. Both of my surgeons have had the same philosophy :
They don't allow any formal PT exercises at all for the first month after a knee replacement. They say your knee needs that time, to start on its journey of healing. For that month, we rest, ice and elevate our leg, and walk around the house.
After that month, we just go to PT once every 2 weeks, where we are shown a few new exercises to do at home.
Their patients all do well and achieve good ROM and mobility, as I did.
After my last TKR, I did no exercises at all. I just let my activities of daily living (ADLs) be my exercise.
Both my knees are strong and reliable. They straighten fully and bend to over 125 degrees. I lead an active life and I can do anything I want to with my knees.
Return to Work
That can be a motivation for many people, but ti can also have a negative effect on recovery, causing some people to push for faster results.
I had no need to return to work, so I could allow my knees to take the time they needed.
However, I did have other incentives to return to full mobility - mainly the desire to continue travelling. I have a daughter who has settled on the other side of the world and I like to spend about 3 months with her every year.
Since getting new knees, I've travelled extensively.
Drive for Success
I think everyone wants their knee replacements to be a success. They wouldn't have gone through this major surgery if they didn't hope their knees would be better afterwards.
Some people interpret the drive for success as following a strict exercise regime. That can backfire on you, as over-zealous exercising can lead to irritated and inflamed soft tissues, and that can delay recovery. We see that a lot, here on BoneSmart.
Other people, just as motivated, realise that resting isn't "lying around, doing nothing." It's working hard, to give your knee the best possible chance of healing well.
It's not exercising that gets you your ROM - it's time. Time to recover, time for swelling and pain to settle, and time to heal. Your ROM is there right from the start, just waiting for all that to happen, so it can show itself.
I certainly had a drive for success. I wanted my active life back. I wanted to be able to play with my grandchildren, to travel to visit them, to lead an independent life, and to see the world.
Since my various knee replacements, I've travelled by land, sea and air, and visited most countries in SE Asia, South America, the US, Canada and Europe.
I'm 76 now and I don't plan to be a rocking-chair granny for a long time yet.
Results
I think those speak for themselves.
I walk well, with no stick or cane. I do carry a cane in my car, for use when the ground is wet or slippery underfoot. I'd rather use a cane then than have a fall.
My knees work so well that I seldom think about them. The only accommodation that I have to make for them is when I'm gardening. I can't squat fully, so I kneel on a foam pad.
After-thoughts
In all my musings, I'm convinced that the most important factor for the success of any knee replacement is the skill of the surgeon - skill in choosing the implant, shaping the bones to receive the implant, fitting the implant, balancing the tendons and ligaments, and in handling the soft tissues gently.
Both my surgeons have been meticulous and I attribute my good recoveries and well-functioning knees mainly to their skill.