Knee surgeon has a better way to operate

Friday, March 2, 2001 | 10:15 a.m.

Rising medical costs and advancements in technology are rapidly ending the days when a surgeon routinely sliced open a patient's knee, making a 10-inch incision to replace all or part of a damaged joint.

Approximately 266,000 total-knee replacements are performed each year, according to the American Academy of Orthopaedic Surgeons. More than 5,000 partial-knee replacements (called unicompartmental replacements) are performed annually.

Modern orthopaedic physicians are being more conservative about how extensive an operation they perform on knees.

One of the latest recruits to a relatively new technique that has been dubbed MIS (minimally invasive surgery) is Dr. Michael J. Crovetti of the Bone & Joint Institute in Henderson.

Crovetti opened his clinic six months ago, after working almost a year with at the Desert Orthopaedic Center, where he applied minimal incision techniques to hip replacements. He said he is excited about the new MIS techniques and instruments.

Crovetti said his clinic is one of 15 sites around the nation working with tools put on the market last November by Zimmer Inc., a Wisconsin firm that designs and manufactures orthopaedic implants and related equipment. It announced in November that it was putting the new instruments on the market.

After about six months the sites will report results of the instruments' performance to the company.

"I was quite honored to be selected," Crovetti said. "They chose physicians that did additional years of training in joint replacement in their initial launch for the program to promote MIS.

"After I finished my residency (in Dayton, Ohio, in 1999) I did another year of training (in Las Vegas) in just doing hip and and knee replacements. I became familiar with the instrumentation."

Crovetti said MIS procedures are less costly and less painful to patients.

"The benefits of MIS are that you are cutting less tissue so the blood loss is less; the trauma to the tissue is less; the operative time is shorter and recovery time is quicker -- the patient is in the hospital two days instead of four," he said.

"We leave the knee as whole as possible. Technology and instrumentation have allowed us to do a lot of different things. If you look at the instruments for knee replacement in the '70s and compare them with today's, the difference is incredible."

MIS involves making a cut of only about 3 inches during partial knee replacement procedures.

The MIS system has been used on different areas of the body, such as the chest, abdomen, spine and pelvis.

MIS operations are done with the aid of a viewing scope and specially designed surgical instruments. The scope allows the surgeon to perform major surgery through several tiny openings, without the need for a large incision.

Surgeons also have for years performed what is called unicompartmental knee arthroplasty, a procedure that involves replacing one of the knee's compartments rather than the entire knee.

However, when making the incision for the partial replacement, doctors used to routinely make the cut the same size as for a full replacement, until MIS procedures were applied to knee surgery.

"It has always been comfortable (for surgeons) when replacing a knee to see as much (of the knee) as possible," Crovetti said. "With a 10-inch incision you can see everything. People have been hesitant to work in smaller areas."

It is similar to going from working on a grandfather clock to a wristwatch, he noted.

"Traditionally, we made an incision almost the same size as a total joint replacement (regardless of what needed to be done to the knee) because a lot of the instruments that were available were just a modification of the total knee replacement instruments," Crovetti explained.

Crovetti said the number of knee replacements will continue to increase as the population lives longer and remains active. Advancement in technology also will affect the number of knee surgeries each year.

He doesn't want to give the impression that MIS is for everybody. "Unicompartmental knee surgery is specific to a specific problem.

Some patients' knees may have problems in more than one compartment, he said.

"If you replace one part of the knee and the other part of the knee maybe still has arthritis in it, you really haven't helped that patient," he said. "They are going to have pain in their knee. Our goal is to be rid of all their pain, not just one area."