Less is not always more. When it comes to knee replacements, total knee replacements have historically trumped partial knee replacements — and for good reason. Knee surgery is complicated business (the knee comprises three joints, which are held together by several ligaments and bones).

Removing the whole package is, on a technical level, an easier maneuver than splicing away at one small section of the knee.

But better medications to control rheumatoid arthritis — one of the causes of knee replacements — and new, image-guided technology for surgery have made partial knee procedures, also known as unicompartmental surgeries, both easier and more accurate to perform.

George W. Bush’s unicompartmental surgeries last July — one on each knee — sparked interest in partial knee procedures. But before you sign yourself up for one, know your knee and trust that your doctor does, too. Because partial knee replacements aren’t for everyone.

Michaela Puno, a 65-year-old competitive ballroom dancer in Reston, Virginia, got to the point where she could hardly dance because of the pain in her right knee from osteoarthritis. She’d had two meniscal tears, and one part of her knee was worn down to the point of being bone-on-bone. But the other two compartments were fine, so her doctor recommended partial knee replacement.

But Puno’s friend, Tessie Marfori, 65, of Alexandria, Virginia, got the opposite recommendation from her doctor. “When [the doctors] saw the MRI, they knew they needed to do the total,” Marfori says. “I probably had no choice because I have rheumatoid arthritis.”

Rheumatoid arthritis, as opposed to osteoarthritis, is an autoimmune condition in which the body’s own immune system attacks its joints. Osteoarthritis occurs when joints wear down. Traditionally, rheumatoid arthritis patients have exclusively been candidates for total knee replacements, but with better medications to control the immune system, these patients can also opt for partial knee replacements, says William Leone, an orthopedic surgeon based in Ft. Lauderdale, Florida, who performs both partial and total knee replacements.

[Read: Is It Possible to Prevent Arthritis?]

When Less Is More

“There’s more of a grey zone now,” Leone says, and that’s opened the door for more partial knee replacement procedures. “The attraction of a uni, when it’s appropriate and done well, is that most people say it feels like a very natural knee.” That’s because more of the knee is left intact: The cruciate ligament — the tough band of tissue connecting the thigh and femur bones at the knee joint — is not removed, nor are many of the neurological pathways interrupted, Leone says. “It’s a much more isolated procedure, and the recovery time is much quicker.”

“For the average person who is going to go fishing or play tennis, it’s a wonderful, elegant way to solve a problem that really interferes with peoples’ lives,” Leone continues.

“If you pick the right person, it can be fantastic,” adds Claudette Lajam, an assistant professor of orthopedic surgery at NYU Langone Medical Center. “There’s quicker recovery and a little less pain and blood loss. The ligaments are still there, and other things are still there.”

And what’s made partial knee replacements easier for surgeons to perform is the advanced guided imaging technology that enables them to visualize knee surgery on a computer screen as they are performing it. “Now there is so much more data, so we can cut more bone. It’s just been eye-opening,” he adds.

But for Puno, recovering from the partial knee replacement procedure has still been difficult. “Every single centimeter where I could bend my knee was an achievement,” she says. “But I’m really glad I did it because [if I hadn’t], I wouldn’t be walking straight.”

Puno says recovering from partial knee surgery has been more painful than the total hip replacement surgery she had several years ago. “They told me that the knee is just a more complicated part of the body,” she says. The one good thing? “My scar is much smaller compared to a total knee replacement.”

[Read: 13 Things to Know Before Your Hip Replacement.]

The Old Standby: Total Knee Replacement

“If a person has arthritis and pain that doesn’t go away when they take medicine, and they can’t function, that’s the time to think about a surgery fix for that,” Lajam says. “The surgery that is most reliable is the total knee replacement.”

“The longevity of a total may be slightly better than unis,” in part because the procedures are more forgiving on a technical level, Leone says. The recovery, however, at least for Marfori, has been predictably tedious, but not too limiting to her lifestyle. “I took my granddaughter to the Reston Zoo two weeks ago,” she says. “Of course I felt a little tired in the evening, but I was cleared to drive and travel after five weeks.”

Having a “coach,” a person to help care for you, is critical, she says. Marfori had a whole army of friends to push her through the hard spots — which meant 25 “heel slides” following the procedure. “After each one, I cried. But you have to do it,” she says.

To people considering surgery, “My advice is don’t wait,” Puno says. “Two years prior to my decision, I was already feeling the pain. You hear about how scary it can be. You want to wait until the very last minute.” Puno tried acupuncture and knee steroid injections, but neither worked. In the end, she says, the operation was worth it. “Before, I was so guarded in everything I was doing. You’re hurting all the time,” she says.

Lajam says that whichever procedure patients opt for, they need to be upfront with their doctor beforehand.

“Be honest with your doctor. Don’t say something doesn’t hurt if you want a smaller operation,” she says. MRIs only tell part of the story. Patients’ own pain reports are equally if not more important, she adds. “If you aren’t honest with them, you might not think it’s important, but it might be very important. Be prepared. Know the medicine you are taking, and if you’ve had surgery or injections before. Be able to say it in a way that gets the message across in a short time,” she says.

[Read: How to Describe Medical Symptoms to Your Doctor.]

More from U.S. News

13 Things to Know Before Your Hip Replacement

How to Lose 50 Pounds Without Really Trying

12 Questions to Ask Before Discharge

Choosing Between Partial and Total Knee Replacements originally appeared on usnews.com