X-Why? The Gender Implant

SAN FRANCISCO, CA--(Marketwire - March 6, 2008) - It has been heavily researched that men and women are in fact, anatomically different. But are they so different they require special and customized replacement parts?

According to the American Academy of Orthopaedic Surgeons (AAOS), over 760,000 total hip and knee replacement procedures -- which help patients to regain mobility and quality of life -- were performed in 2005, including:

-- 235,000 total hip replacements

-- 125,000 patients were women and 108,000 were men

-- 534,000 total knee replacements

-- 335,000 patients were women and 176,000 were men

Until recently, orthopaedic surgeons chose from an array of standard implants which were designed to fit both men and women patients. However, the statistics show a larger percentage of women need joint replacement surgery. This factor along with recent advances in technology, have sparked the release of gender-specific knee implants, claiming to offer women a "better fit."

"Women represent two-thirds of patients getting knee replacements," said Aaron Rosenberg, MD, professor in the Department of Orthopedic Surgery at Rush Medical College, Chicago. Dr. Rosenberg was involved in the development and production of the Zimmer Gender-Specific Knee, which hit the market less than a year ago. "The generic implants we had in the past were never specifically designed to fit a woman," noted Dr. Rosenberg."

"The distal femur (thigh bone) in a woman's knee has a distinctly different shape than that of a man's," said Dr. Rosenberg. "A woman's hip rotation is also different and these differences can be addressed in the implant design. Historically, the success of knee replacement has been linked to improving the way these implants fit the broad range of normal human anatomy, and this is another step in that direction for what is clearly a distinguishable and rather large group of patients," noted Dr. Rosenberg.

According to Joshua Jacobs, MD, "In many cases, these gender-specific implants actually do fit a woman's anatomy better." Dr. Jacobs is associate dean for Research Development of Rush Medical College, Chicago, and associate chairman for Academic Programs in the Department of Orthopaedic Surgery. "The question we then need to ask ourselves is does a gender-specific implant affect a patients' clinical outcome."

The question Dr. Jacobs poses remains unanswered. Gender knee implants have not been on the market long enough for orthopaedic researchers to do long-term clinical outcome studies.

However, physicians can assess the long-term clinical outcomes on regular, non-gender specific implants, as a baseline. Two new studies, presented today at the AAOS 75th Annual Meeting in San Francisco, suggest a woman's clinical outcome is no different than a man's outcome when using regular, non-gender, standard specific implants.

One study looked at the survivorship and clinical outcomes of both men and women who underwent a hip replacement with a regular, non-gender, standard specific implant. The study's lead author, Robert Barry Bourne, MD, FRCSC, Professor, Department of Surgery, Division of Orthopaedic Surgery, University of Western Ontario, London, Ontario, Canada, studied over 3,400 patients who underwent total hip replacement. His sample included: 1,941 women and 1,537 men.

He found that women demonstrated greater life of the implant, but little statistical difference in clinical outcome scores. "This leads one to question the need for a gender implant," said Dr. Bourne.

"One goal in knee replacement surgery is to pick the implant that fits the patient the best," said Dr. Jacobs. "This is done on an individual case-by-case basis. While the gender implant is not a necessity in every case, it does offer additional sizing options and allows the surgeon to use an implant that may be a better fit for the patient's individual anatomy."

Dr. Jacobs will sit on a panel along with Dr. Rosenberg, Dr. Bourne, Andrew Glassman, MD, and Timothy Brox, MD and debate, "X-Why? The Gender Implant -- Necessity or Trend?" at a media briefing to be held Thursday, March 6, 2008 at 8:30 a.m. at the Moscone Convention Center, San Francisco in room 224.

Editor's Note: Full industry relationship disclosure information for each AAOS media briefing participant is available upon request. Please contact Catherine Dolf, (Cell) (847)-894-9112 dolf@aaos.org or Lauren Pearson, (Cell) (224)-374-8610 lpearson@aaos.org for more information.

AAOS Gender Knee Technology Overview

Dr. Bourne's abstract P041

Tim Brox, MD abstract P172

About AAOS

To view this release online, go to: http://www.pwrnewmedia.com/2008/aaos030608_brief_genderimplant/index.html

Contact Information: For more information, contact: Lauren Pearson (224)374-8610 (847)384-4031 Catherine Dolf (847)894-9112 (847)384-4034