The implant addresses three distinct and scientifically documented shape differences in women's and men's knees. Designed using three-dimensional computed tomography imaging, the Gender Solutions High-Flex Knee more closely mimics the joints and inner workings of women's knees.
"We'll be the first in Dallas to use the new design," said Dr. Robert Bucholz, chairman of orthopaedic surgery at UT Southwestern. "This is one in a series of technical improvements in the design of knee implants that is long overdue."
During total knee replacement surgery, or arthroplasty, surfaces of the thighbone (femur), the shinbone (tibia) and the kneecap (patella) are replaced with a metal-and-plastic implant.
Traditionally, the implants have been designed based on men's knees. For women, smaller implants were used, but size did not resolve the anatomical differences, which sometimes accounted for pain and discomfort and an "awkward" feeling.
Researchers have found numerous shape differences between the average male and female knee. The new replacement, created by Zimmer, Inc., of Warsaw, Ind., and approved in May by the Food and Drug Administration, addresses three gender-specific issues:
- Narrower shape: Knee implants are typically sized by measuring the end of the femur from front to back and from side to side. Most women's knees are shaped like a trapezoid and narrower from side to side; men's knees are more rectangular. Implant size is typically based on the front-to-back measurement to allow the knee to move and flex properly. In women, however, an implant that fits from front to back can be too wide from side to side, sometimes causing it to overhang the bone.
- Thinner density: Typically, the bone in the front of a woman's knee is less prominent than in a man's. After traditional implantations, some women describe a "bulky" feeling in the joint despite better function. The front of the new implant is thinner so the replacement more closely matches the female anatomy.
- Tracking: A woman's femur attaches to the tibia at a slightly different angle than a man's because most women have wider hips. The angle difference between the pelvis and the knee joint — taken into account with the new implant — affects how the kneecap tracks over the end of the femur as the knee moves through a range of motion.
Dr. Bucholz said about 80 percent of knees are replaced because patients suffer from osteoarthritis. The condition causes the cartilage that cushions the bones of the knee to soften and wear away. The bones then rub against one another, causing knee pain.
The number of joint and knee replacement procedures performed by orthopaedic surgeons is increasing due, in part, to aging baby boomers and an increasingly overweight population. In the 1950s, the first artificial knees were little more than crude hinges; now there are a variety of knee-replacement designs that take into account age, weight, activity level and overall health.According to the National Institutes of Health's consensus statement on total knee replacement released in February 2004, the surgery is highly successful and is supported by more than two decades of follow-up data.
"It is one of the most successful elective procedures that we perform," said Dr. Bucholz.
Each year, more than 400,000 patients undergo total knee replacement surgery in the United States and nearly two-thirds are women, according to the latest National Hospital Discharge Survey, which is compiled by the U.S. Department of Health and Human Services.
At UT Southwestern University Hospitals, orthopaedic surgeons annually perform about 450 knee replacements. Surgeons use time-tested protocols for surgical technique, pain management and rehabilitation. They also provide an array of other reconstructive procedures for the hip and knee.
For more information on knee-replacement surgery at UT Southwestern University Hospitals, please call 214-648-3065.
Connie Piloto | EurekAlert!
New technique to treating mitral valve diseases: First patient data
22.08.2017 | Universitätsspital Bern
New bioimaging technique is fast and economical
21.08.2017 | Rensselaer Polytechnic Institute
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences