CHICAGO -

Diane Shaughnessy knows the pain of ankle arthritis.

"It's as if a vice was constantly being turned and squeezed," Shaughnessy said. "Go to bed with pain, sleep with pain and wake up with pain."

Joey Meyer has had similar experiences.

"It was grinding. Sometimes, it would catch, and I'd just drop to my knees," Meyer explained. "Life was not a whole lot of fun."

Doctors used to fuse ankles to relieve the pain, but that meant very limited mobility. Now there's ankle replacement surgery.

With an ankle replacement, surgeons remove abnormal bone and cartilage and insert a metal and plastic implant. Newer implants mimic the human ankle and allow for better rotation and movement.

Doctors can also treat more patients with a variety of injuries. In fact, between 2011 and 2012, the number of ankle replacements doubled.

After a replacement, patients can enjoy almost any low impact activity, but running is not recommended.

"For me, it's very gratifying to restore function instead of just improving upon abnormal function." said Dr. Johnny Lin, orthopedic surgeon at Midwest Orthopedics at Rush.

Now, Shaughnessy and Meyer can enjoy life without pain.

"I walk. I do the elliptical. I ride the bike. I mean, I do a lot of things now, and the ankle's fine," Meyer said.

Doctors believe ankle replacement will last about 15 to 20 years, which is what any joint implant is expected to last.

Candidates are those over 50 years of age with severe arthritis that doesn't respond to medications. Patients cannot be severely overweight to qualify for the procedure.

DOWNLOAD and VIEW research summary and an in-depth interview with the doctor