SHOULDER JOINT REPLACEMENT TECHNIQUE RELIES ON SUCTION

By Jeremy Olson, World Herald Staff Writer

R. Michael Gross M.D.

An Omaha orthopedic surgeon has come up with a new shoulder joint replacement technique that he thinks will better relieve pain and reduce the need for follow-up surgeries.

By inserting a suction device into the shoulder blade during surgery, Dr. Michael Gross found it easier to implant and cement the plastic and metal replacement parts that act as the shoulder's ball and socket.

The bones of the shoulder joint fit together like a cup and saucer. The cup is the dome-shaped top of the humerus bone, which runs from the shoulder to the elbow. The saucer is the glenoid cavity, which faces out from the edge of the shoulder blade.

Replacing these parts -- the top of the humerus with a metal replica and the glenoid cavity with a plastic replica -- can relieve pain and increase motion for people suffering from degenerative diseases such as rheumatoid arthritis or from osteoarthritis. Thousands of shoulder joint replacements are done every year, although knee and hip replacements are more common.

A problem with this shoulder surgery though is a loosening of the glenoid replacement over time. One 1997 study estimated that this occurs in 44 percent of patients within 12 years of their surgeries. The resulting discomfort can require follow-up surgeries.

"That's a high failure rate," said Gross, who is affiliated with Omaha's Alegent Health System.

Gross said the problem stems from the rapid amount of bleeding that occurs in this type of shoulder surgery, which diminishes the adhesiveness of the cement.

Properly placed suction clears out the shoulder joint for the 10 minutes needed for the cement to adhere the glenoid replacement to the bone, Gross said. Additionally, he said, it creates a negative air flow that draws the cement to the bone and creates a snugger fit.

"I could see the cement literally disappearing into the bone, just literally pulling into the bone," he said. "It's the same as a sponge."

After sorting out this procedure through research and tests on cadavers, Gross has performed the technique on 30 patients with early success. He will present his results at this weekend's annual meeting of the American Academy of Orthopaedic Surgeons in Dallas.

He also reached a deal with Zimmer, Inc. -- a spin-off-company from Bristol-Myers-Squibb that makes shoulder joint replacement parts -- to have other doctors across North America test his procedure.

His solution faces competition, even at this weekend's conference. Surgeons from California are reporting success using a plastic-and-metal replacement part for the glenoid cavity that is screwed and grafted to the bone and doesn't require cement.

Doctors in Oregon and Texas say that replacing only the top of the humerus bone and not the glenoid can yield equally positive results for patients with rheumatoid arthritis and avoids the glenoid problem.

An important part of the deal with Zimmer, Gross said, is that the company is organizing a long-term study of whether his innovation provides better results for patients. Time and research will tell.

"This is the way I can solve a problem," he said. "Can we do the operation and do it in a way that will last, so the first operation is indeed the last operation?"

This Page Updated On:   06/05/2002 02:44 PM