September 27, 2003

By: Mark Harris
Website: http://www.bearing-n-bearings.com

Commonly known as an operation for the elderly, more younger patients are now requiring joint replacements with ceramic-on-ceramic bearings

It used to be thought of as only a disease that struck the elderly with brittle bones, but now more and more patients are being diagnosed with osteoarthritis hence requiring total joint replacements at a much younger age. And, the challenge for surgeons is making the prosthesis last long enough so that the patient doesn't require a second operation in their lifetime.

According to James A. D'Antonio, M.D., orthopaedic surgeon and clinical researcher with Greater Pittsburgh Orthopaedic Associates (GPOA), another challenge is the fact that younger patients are more active, therefore harder on the joint being replaced. "Traditionally younger patients recover quicker, but are much more prone to wear and tear on the joint due to their active lifestyle."

Typical age for joint replacement is 65 - 75 years of age, but Dr. D'Antonio notes he is now seeing more patients in the 35 - 55 age bracket. In fact, one-half of the total joint procedures he does in a year are now in that younger patient population. "We can't neglect this very important patient population, and we must address the concerns about the longevity of these total hips in the young and active patients."

Current hip replacement surgery provides increased function, greater mobility and pain relief for hundreds of thousands of patients every year. The constant friction, however, of the metal ball against the plastic cup can cause the prosthesis to wear out after only 10 - 15 years.

Now, a new type of replacement device - ceramic-on-ceramic - may overcome this problem. According to Dr. D'Antonio, one of the lead investigators in the United States to study ceramic-on-ceramic bearings for total hip replacements, "the harder surface and improved bearing may increase longevity by preventing inflammation and bone loss caused by excessive friction and wear."

The project is ongoing in ten U.S. sites and calls for the implantation of 500 total hip arthroplasties in a prospective randomized study. Dr. D'Antonio has completed his portion of the study, implanted 90 study patients and has petitioned the FDA to permit the continued use of these unique bearings because of the obvious benefits. Ceramic-on-ceramic bearings have 500-fold less wear than current bearings and may solve the problem of wear and bone resorption in the future. In fact, 60-year-old Jack Nicklaus recently received a ceramic-on-ceramic hip when he underwent hip replacement surgery.

It was originally thought that the cement used to secure the hip prosthesis in the socket caused it to fail. To overcome this problem, new devices with porous surfaces were developed so bone could grow into the surface. Many of these eventually failed in much of the same way as the cemented devices - the metal head rubbing against the plastic socket caused microscopic pieces of plastic or debris to shed into the surrounding membranes. Because the body cannot digest plastic, however, it digests bone, which eventually causes the device to loosen. The patient experiences pain and loss of mobility and revision surgery becomes necessary. Alumina ceramics are harder and more durable than plastic, have much lower friction and lubrication and generate considerably less wear debris.

The bearing surfaces of hip replacements have changed very little in the last 30 years, but the ceramic-on-ceramic device may represent the next generation for hip replacements, especially for the younger patient.

There are several reasons why younger patients are requiring total joint replacements. The most common is premature or early osteoarthritis. This can be a result of increased wear and tear, secondary to trauma or sports-related activities.

Mike King, 39 year-old from Wexford is an example. King developed osteoarthritis in his right hip from playing hockey and other sports since his teenage years. He was also captain of his hockey team at Allegheny College in Meadville and admits taking some hard hits. But King endured the pain for another 19 years until it became so severe that he finally had a ceramic total hip replacement in December 1998. "People are surprised that I had my hip replaced at such a young age. I am glad to know that this hip will last longer than traditional ones, and hopefully I will not need a revision." The operation and rehabilitation had King out of the office for a month, but he has now fully recovered and is back to work at Merrill Lynch as a stock broker and back to his active lifestyle.

"I feel great - I can do things I enjoy again such as unlimited biking and golfing. In fact, for the first time I was able to catch my seven-year old son without hopping on one leg ," said King, father of four children. "I have so much energy now, I feel like a kid going to camp everyday."

About The Author:

Mark Harris is a successful author and regular contributor to http://www.bearing-n-bearings.com.  Keep things running smoothly with ball bearings, roller bearings, ball thrust bearings and tapered bearings.