The former No.1 was diagnosed with the auto-immune disease just before the US Open earlier this summer.
Caroline Wozniacki has revealed she has been struggling with rheumatoid arthritis over the last few months.
The former No.1 was diagnosed with the auto-immune disease just before the US Open earlier this year but managed to play through the pain barrier.
The Danish star began her year with her maiden Grand Slam title, when she won the Australian Open, before her season ended with a defeat to Elina Svitolina at the WTA Finals.
Wozniacki will now use the off-season to plan how to manage the illness, which causes swelling of the joints and fatigue.
She told a press conference: "In the beginning it was a shock. Just you feel like you're the fittest athlete out there, or that's in my head, that's what I'm known for, and all of a sudden you have this to work with.
"It's obviously not ideal for anybody and I think when you're a professional athlete, it's also not even more ideal. But you find a plan, figure out what to do, you do your research, and thankfully there are great things now that you can do to it and do about it.
She hopes to return to center stage for the 2019 season.