In the Curse of Strand adventure, the following information is provided about the NPC Ezmerelda in Appendix D (p. 231):
Ezmerelda's Secret ... On one of her less successful adventures, a werewolf bit off her right leg below the knee, and although she avoided being afflicted with lycanthropy, Ezmerelda was sidelined for months. She commissioned a master artisan to craft a prosthetic lower leg and foot. After several tries, he delivered a prosthesis that restored her mobility. She has since adapted well to the false appendage and takes care to hide it from view.
There's also this magic item that can be found in the village of Krezk (p. 148):
The gravestone marked X is carved with roses and bears a 3-inch-diameter sun-shaped indentation on its east side. Engraved beneath the indentation is the name PETROVNA. If Tasha Petrovna's holy symbol (see chapter 4, area K84, crypt 11) is placed in the indentation, both the holy symbol and the indentation vanish. Then read:A ray of golden sunlight breaks through the clouds to the west and shines upon the grave. The fog and the gloom shrink from its brilliance as the sunlight causes the gravestone to crack and crumble, revealing a ring within.
The sunray lasts for 1 minute. If the characters smash the gravestone without placing Tasha Petrovna's holy symbol in it first, they find nothing within its remains. The ring is a ring of regeneration.
The description of this magic item in the DMG says (p. 191):
While wearing this ring, you regain 1d6 hit points every 10 minutes, provided that you have at least 1 hit point. If you lose a body part, the ring causes the missing part to regrow and return to full functionality after 1d6 + 1 days if you have at least 1 hit point the whole time.
So the question is:
If the party found this ring of regeneration and gave it to Ezmerelda (either by coincidence or because they learned of her "secret" and wanted to help), would her missing leg grow back? Is there any reason this wouldn't work (such as due to the length of time her leg has been missing, or the fact that her leg has now been replaced by a fully functioning prosthetic)?