You've been told you need a TKR...and that's scary. Being on this site and getting to know what's ahead of you is a major step because the more information you have, the better prepared you'll be. If your doc says that a TKR is your only option and your quality of life is pretty much zero, then you should consider getting the op done as soon as possible. At 20 months post-op, I have no regrets, regardless of the three biggest issues: the intense but short-term pain, the amount of work it takes to return to normal and length of the recovery. However...
There is Synvisc, and products like it. After 4 knee scopes (two each side) plus arthritis left me hanging in my 50's, the doc used Synvisc (three shots, days 1, 8 and 15) to keep me going for 5-6 years when I was living in New Jersey. Each round lasted close to a year. Moved to the warmth of Texas in 2010 and that change in climate left me pain-free for another five before needing the TKR. No guarantees but Synvisc worked amazingly well for me. I asked the doc about more of it in January 2016 before the TKR in March and he told me that the left knee was so bad that the injections would do very little for me at that point so I bit the bullet and did the op. Just a thought...talk to your surgeon.
The most difficult part of facing the reality of a TKR is that, going into the op, no one knows how difficult or long their recovery will be. There are very, very few people who have quick (less than 3 months) or lengthy (greater than 18 months) recoveries. For the vast majority of us, this takes a year...accept it. People typically return to work in the 4-6 month range depending on how well they've recovered, age, type of job, and many other factors. You cannot expect to be "OK" in three months...you just can't. You may be lucky and end up with a fast recovery buy you cannot count on it.
On the subject of returning work, a sedentary desk job is easier to return to than construction, delivery, nursing, etc., all those professions which require a lot of walking and leg strength. Even those at a desk report a lot of pain and swelling when finishing the day after sitting so long.
The problem is that you cannot push a knee to recovery. Try, and it bites you back...big time. Pain, swelling, exhaustion, inability to walk, etc. I once did 8,200+ steps at 5 weeks and paid for it with a "balloon knee" for three days. The knee heals gradually. It will take you up to 3 months just to get your ROM back to at least 0 / +120...then you have to rebuild the strength in your dead quads, glutes and core to walk properly, climb stairs, etc. That takes up to a year post-op. By 8 months, I was doing 11,000+ steps (5 miles) with no ill effects...but it took time, work, patience and a healthy respect for the new knee. Most people report "feeling like themselves again" at 9-10 months and rejoice at their "full recovery" on their one-year anniversary...very common.
THIS IS IMPORTANT: For a TKR, there can be no expectations, no timetables. It is the most Zen of all surgeries: "Your knee will be better when it's better." Anyone promising you that you will be fully recovered and back to work in 3 months is delusional. I'm not saying it's impossible as we've had a few of those unlikely success stories reported on the Forum, but those are very rare.
So, if you have this question in your mind: "Will I make it through three months?", the answer is OF COURSE! It will painful, difficult and challenging. Will you be able to go back to work at that point? The truth is: Not likely. The problem for you (and for all of us at the beginning) is that you never know the real answer to the question of time to recovery and no one can predict how recovered you will be any point in time.
If you want to read about the realities of recovery from my personal perspective and after reading thousands of posts, I've posted a lot of discussions about pain, sleeping, depression and many more on the Forum. Click on my name or picture and then "See All Discussions".
The one great thing you're doing is educating yourself about the op. Virtually all of us were told nothing pre-op and we all had the same impossible expectations to deal with afterward. The truth is that it's a brutal operation with a lot of pain to endure in the first 30 days or so. Then it takes a lot of PT and work at home to regain your ROM followed by walking and strength exercises to build back all that musculature. All of this takes time...you just don't know how much at the beginning and no one can predict the length of your recovery.
In the end, it's not scary at all. You go to sleep, wake up and have a new knee. Simple. Then you start to walk IMMEDIATELY. Manage the pain, ice, elevate, eat healthy, hydrate a lot, do the necessary work. The pain will fade and you will find that all your original pain will be gone too. In a year, you will be sooooo glad you took the time and did the work to lead a pain-free, normal life again. Well, almost normal. There will be things you will NOT do anymore like running, jogging and competitive sports...but that list is in another post... I played hockey for 45 years and had to give it up...not easy emotionally but a no-brainer choice. Stay strong...take your life back.