Florida - When Tracy Fosterling first met her dog, Lily, she didn't realize what the poor four-legged friend was suffering from, but one thing was for sure: She would do anything to help her.

Tracy discovered two-year-old Lily on Facebook, where the previous owner put her up for sale.

Lily's previous owner was reportedly "overwhelmed" with the dog, whose deformed hind legs prevented her from walking normally.

So, in July 2021, Tracy decided to buy the Great Pyrenees from him, not knowing what she had gotten herself into.

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"It was a really sad sight to see, and looking back on videos of that time still makes me so upset," she recalls.

She and her partner initially suspected that Lily might have been kept in too small a cage or suffered from broken legs.

"She physically couldn't straighten her legs," the Florida native told Newsweek, "But other than that, her spirits were so high."

Tracy took Lily to several vets in the area, where the dog underwent several tests, but it took an orthopedic surgeon to find out the true cause of the poor animal's distorted gait.

He diagnosed Lily with bilateral luxating patellas, meaning her legs were "permanently dislocated outwards."

Unfortunately, the prognosis wasn't the best for Lily, as Tracy revealed the vet had said the pup had "one of the worst cases they had ever seen."

The Great Pyrenees then underwent surgery in September 2021 and again in February 2022, then had to be carried everywhere by her new owner for months.

"She was confined to a pen for several months, only getting in and out with me carrying her," Tracy said. "This was essential to making sure the surgeries worked since her condition was so severe."

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A long rehab period was then on the schedule. "The whole process was about one-and-a-half years."

But Lily and her owner's perseverance paid off - the dog can now fully extend both knees again, which means she can finally walk properly!

"It makes me so happy. I see old videos of her and almost cry. I couldn't believe someone let her get that way without helping her," Tracy said.

In a TikTok video, Lily's owner showed off her incredible before-and-after, calling the healing process one of her "biggest accomplishments" in life.