Oh, I am so sorry this is happening to you. I would try and find another surgeon!! There are way to many of us here that are happy with our total replacements, and are having no real issues with being athletic and active to believe this surgeons negative predictions.
As you said, we have a lot of athletes with not one, but two total knee replacements!! The total knee recovery will be just the same as the recovery from your partial.
Don't let it get too much worse my dear. The sooner the partial is revised to a total, the better your outcome will be. Don't let the existing arthritis continue to degenerate.
I know no one wants to think about another surgery.the medical costs, the recovery time, etc, all make it a huge consideration, but you are in pain now and not being able to enjoy your life the way you want to, and it will only get worse.
There is a surgeon out there that will respect Your athletic lifestyle and make it work for you.
As far as ROM, you are fit and flexible now, and there is no reason you won't be after a TKR!! Skigirl has a ROM of 148-150. I am not an extreme athlete, and mine is 150!!
Skigirl and I both have Stryker implants. It seems Stryker implants are designed for better flexation. Some implants are only designed to get to a max of 135. Now that is just fine for most folks, but for an athlete, maybe that won't be satisfactory and that may be why your current surgeon is saying you won't be happy.
Find a good surgeon, and research the Stryker implants ( the Stryker Triathlon). I would NOT tell someone to go for one implant over another, as they all serve their purpose and are great, I am just giving my firsthand information from my surgeon.
Each surgeon has their favorite implant to use. The ones he has gotten proficient and comfortable installing for whatever professional reason. Skill of the surgeon is still key with this surgery no matter which implant the surgeon uses.
Best of luck to you dearheart.