BARTOW - Orthopedic surgeons at Bartow Regional Medical Center are getting a helping hand from a robotic arm.

The robotic arm is part of an interactive orthopedic system for partial knee resurfacing, sometimes called unicompartmental resurfacing.

Bartow Regional is the first hospital in Polk County with the MAKOplasty system, in which the surgeon uses 3-D modeling, computer assistance and the robotic arm to resurface damaged sections of the knee.

Other hospitals using it nearby include Tampa General Hospital, Florida Hospital Orlando, Florida Hospital Zephyrhills and Brooksville Regional Hospital. Mayo Clinic Jacksonville also has surgeons using it.

"The CT scan tells the computer every nuance that knee has," said Dr. Maury Fisher, an orthopedic surgeon certified to use the system at BRMC. "It knows exactly what the knee looks like."

Unlike a total knee replacement, partial or unicompartmental knee resurfacing removes bone and cartilage in one or two compartments of the knee. Implants then are installed.

This is an alternative to full knee replacement for people whose damage isn't affecting the whole knee but still causes them pain that other treatments aren't controlling. The knee has three compartments. One is behind the kneecap. Another is on the outer side of the knee, and another is on the inner side of the knee.

People with early or moderate osteoarthritis may have damage in only one or two.

"If just the kneecap is bad, why replace the other two compartments?" Fisher asked.

Partial knee resurfacing has been available in Polk County for awhile from some orthopedic surgeons.

The MAKOplasty procedure is what's new here, although the first one in the U.S. using that method was done in 2006, according to Bryant David, one of the MAKO Surgical Corp. specialists working with BRMC.

Fisher said he hasn't considered previous equipment for partial resurfacing as good as that for total knee replacement.

This system, bought by BRMC for about $1 million, has persuaded him to start doing them for appropriate patients. He expects it to give more accurate and "bone sparing" cuts, allowing for more longevity with the implants.

This is part of the Bartow hospital's effort to establish itself as a countywide orthopedic center, along with its announcement this spring of a physician partnership to provide 24-hour on-call orthopedic coverage in its emergency department.

Surgeries using the new system are expected to start in August. Dr. J.C. Alvarez and Dr. Stephen Beissinger are certified, with Dr. Brian Jurbala getting trained, BRMC spokeswoman Susan Sartain said.

Partial knee resurfacing doesn't prevent total knee replacement in the future if needed.

BRMC is holding an open house from 5 to 7 p.m. Thursday to showcase how the system works.

Orthopedic surgeons at Mayo Clinic Jacksonville have done almost 100 cases with MAKOplasty since acquiring the system in November 2010.

"We're very pleased with it," said Dr. Cedric Ortiguera, one of Mayo's orthopedic surgeons. "It gives us the expected outcomes, and patients are recovering well."

The incision is smaller than with traditional surgery, he said, adding:

"The biggest advantage is it allows us to be more accurate with placement of the implants, which is more likely to lead to better long-term outcomes."

The knee operation takes place with the orthopedic surgeon standing beside the knee, guiding an instrument with a cutting burr on the end. The incision typically is 4 inches to 6 inches, according to MAKO Surgical.

On a large computer screen, a white image of the 3-D knee almost appears to glow. The area to be removed is highlighted in green.

As Fisher moved the burr in a demonstration, parts of the green disappeared, indicating removal of the targeted area.

It some respects, the image on the screen looked almost as if he were painting by the numbers.

Except that the system blocks attempts to travel outside the areas slated for removal.

"It makes you stop," David said. "It won't let you go any farther."

The method allows results "substantially more accurate than I can do with my naked eye," Fisher said.

"The computer will only allow me to take off the amount of cartilage and bone needed so I can put the replacement in there." He emphasized that the orthopedic surgeon still is guiding the removal, adding, "They call it a robot only because it keeps me from doing what I shouldn't do."