Medically reviewed by Eric Heimberger, MD McLeod Orthopaedics Seacoast
The fact that our hip or knee joints wear out shouldn’t surprise us. Consider this: forces 4 to 8 times our body weight are exerted millions of times each year on our hip and knee joints. If you are considering hip or knee joint surgery, you may also be interested in learning more about the materials used in hip and knee joint implants, along with some advantages and disadvantages of each.
KNEE REPLACEMENT MATERIALS
The knee is a more complicated joint than the hip. There are more than 150 different knee implant designs available. Most use polyethylene that has been treated to interlace and tightly bind the molecules for the platform on the top of the lower leg (tibia) and the bottom of the upper leg (patella).
This Ultra-High Molecular-Weight Polyethylene (UHMWPE) has more than 40 years of clinical history.
The metal parts, onto which the plastic is bonded, usually are comprised of titanium or cobalt-chromium-based alloys.
Most knee joint replacements can last 10 to 15 years or even longer, depending on your activity level.
BASIC HIP JOINT MATERIALS
Developments continue to emerge that improve the life of a hip replacement by reducing wear and improving strength. Today’s hip joint implant has 4 parts:
The stem and shell pieces are either cemented into the bone or inserted in a way that the bone will grow into and hold the metal pieces into place.
There are 4 basic combinations that are used in making hip implants:
Be an informed patient. Ask your Orthopedic Specialist what he or she plans to use in your joint replacement and why. Your overall health, fitness, weight and age will play a role in the ultimate decision, as will your surgeon’s experience with various manufacturers, designs and implant materials.
Find an Orthopedic Specialist near you.
Sources include: McLeod Health, National Institutes of Health, American Academy of Orthopaedic Surgeons, Center for Orthopaedics, Bonesmart.org