One word of caution - the surgery itself (without the necessity of rehab) takes quite a bit out of the body. I had my first hip replacement surgeries just 7 weeks apart when I was 54 - my work travel schedule dictated it. Although the hips were healed, my body took almost a year to completely recover and just working full time was tough - travel was awful.
When I had to have them done the second time 5 years later (recalled implants - failing and affecting my health) my surgeon insisted on 3 months between the 2 operations. Then I needed an emergency revision one week after the second operation. Finally, I proceeded to have orthopedic surgery on my hand 3 months later. So 4 surgeries in 6 months - my body rebelled and it took over a year to completely recover strength and energy.
So give your body time to heal and get your energy back before the second TKR
Sue