Total Knee Replacement: The Changing Patient Landscape and

Press Release:

Total Knee Replacement: The Changing Patient Landscape and Advanced Procedures

Press Release
News Article February 2005

WASHINGTON, Feb. 24 /PRNewswire/ -- As the demographics and demands of today's total knee replacement patients change, the procedures and technology used by orthopaedic surgeons are transforming to ensure patient safety and improved outcomes. At a panel briefing of the American Academy of Orthopaedic Surgeons' 72nd Annual Meeting, experts discussed how to balance knee replacement patients' changing needs with state-of-the-art techniques available in surgery today.

The profile of today's average knee replacement patients has shifted from sedentary individuals in their late 60s and early 70s, to active adults in their 50s. These younger patients come to surgeons' offices with dramatically higher expectations than previous generations -- particularly as it relates to the function of the new knee.

"Because of direct-to-patient marketing by the orthopaedic industry, patients are coming in with information from the Internet or some advertisement and are asking us for specific techniques or implants," said William J. Maloney, MD, professor and chairman of the department of orthopaedic surgery at Stanford University School of Medicine, Stanford, Calif. "This raises some controversial issues, especially when patients request specific surgical techniques, such as minimally invasive surgery, and rehabilitation methods." Only a surgeon should recommend which procedure is best, based on his or her experience and each patient's individual circumstances.

Minimally invasive surgery (MIS) for total knee replacements refers to performing the operation with a smaller incision. More importantly, it means not traumatizing the muscles around the knee. This less invasive procedure is performed by only a small percentage of orthopaedic surgeons, however. If surgeons succumb to patient demand and perform the MIS procedure without proper training, it can cause serious patient complications.

Michael A. Mont, MD, director of the Center for Joint Preservation and Reconstruction, Sinai Hospital, Baltimore, discussed a new minimally invasive lateral approach to the knee that does not require any splitting of the muscles. Its best outcomes allowed patients to run two weeks later and exhibit normal walking patterns, but despite this early success, he offered strong words of caution. "Although we have seen some of the best results in the world with this technique as well as with other minimally invasive techniques, we have also encountered problems," Dr. Mont explained. "Patients need to realize that these techniques are still in development and require further analysis to assess their true role. These newer procedures are not for everyone."

Orthopaedic surgeon Douglas A. Dennis, MD, medical director, Rocky Mountain Musculoskeletal Research Laboratory, Denver, is particularly alarmed by some catastrophic complications he has observed from minimally invasive procedures he did not perform. These include a lacerated popliteal artery (the major artery leading to the lower leg and foot), cut ligaments leading to knee dislocation, and even skin necrosis (death of the skin), which occurs from excessive pulling on sensitive skin around the knee so the surgeon can see with limited exposure. More commonly, a knee joint may be malaligned, because it is inherently more difficult to align a knee with less exposure.

To study whether or not performing MIS on the knee puts patients at any greater risk, a team of orthopaedic surgeons including Peter M. Bonutti, MD, Bonutti Clinic, St. Anthony's Memorial Hospital, Effingham, Ill., initiated a prospective randomized multi-center study of 80 patients with six surgeons at a half dozen medical centers. The study included 40 patients with a standard total knee replacement and 40 patients with a MIS total knee replacement. At 12-week follow-up, the team found that there were no differences in the two groups in terms of traditional knee measured criteria. As a result of their study, the researchers found no difference in MIS compared to traditional knee replacement in terms of traditional knee-measured criteria from standard measurements used in orthopaedic surgery.

"This is an important study because our first responsibility is to prove the safety and efficacy of an MIS approach," said Dr. Bonutti. "We can now focus on studies that measure patient satisfaction improvements as we continue to evolve the technique."

Another issue is materials, as traditional implants used over the past three decades have limitations. Dr. Maloney explained that while the traditional implants have been great, they are not going to withstand the high impact forces to which today's active patients may subject them. New materials that wear better may be needed, such as a highly cross-linked polyethelene insert in the bearing part of the knee implant.

Essentially, this polyethelene (plastic) insert replaces the cartilage in the natural joint, which has worn away because of osteoarthritis or some other problem, and is sandwiched between the femur (thigh bone) and the tibia (leg bone) during a knee replacement procedure. This type of insert supports the weight of the body and allows the femur to glide over the tibia. While traditional polyethelene wears over time leading to implant failure, especially in highly active patients, this newer, extra dense material with additional bonds (thus is "cross-linked") at the molecular level has the capacity to wear for a longer time. The tradeoff is that it comes with an increased risk of implant breakage -- hence the concern and the controversy.

"We are probably going to need further generations of these materials to actually accomplish the goal of providing some of our younger patients with the wide range of flexibility, movement and durability they expect from their new knees," said Dr. Maloney.

An orthopaedic surgeon is a physician with extensive training in the diagnosis and non-surgical as well as surgical treatment of the musculoskeletal system, including bones, joints, ligaments, tendons, muscles and nerves.

This press release is provided in good-faith by Chiltern Magazine Services Ltd ("CMS") as a service to users of www.telecomsinfo.com. Whilst all care is taken in sourcing and preparing material includede here, any error or incorrect content cannot form the basis for any legal action against the site-owner. Users are advised to check the accuracy of any statements before relying upon them. Likewise, any forward-looking statements made by the author of the press release should be treated as such.

CMS, P&A House, Alma Road, Chesham, Bucks. HP5 3HB, UK
Tel: +44 (0)1494 771734
Fax: +44 (0)1494 778994
e-mail: Editor, CMSinfo

For more information about us, visit CMSinfo.