Prosthetic materials play a pivotal role in the success of hip and knee replacement surgeries. They must possess attributes like durability, biocompatibility, and wear resistance to ensure they function similarly to natural joints and last as long as possible.
This guide delves into the common materials used in hip and knee prostheses, compares their use in both types of replacements, and highlights the latest advancements.
Your Patient Coordinator is on hand to give you all the information you need.
Metal Alloys
Cobalt-Chromium Alloys
Properties: High strength, exceptional wear resistance, and good biocompatibility.
Usage: Predominantly used in the femoral component of hip replacements and both the femoral and tibial components in knee replacements.
Benefits: Offers longevity and durability, making it ideal for younger, more active patients.
Drawbacks: There is a small risk of metal ion release which can cause local tissue reactions.
Titanium and Titanium Alloys
Properties: Known for their strength, lightweight, and excellent corrosion resistance.
Usage: Used in both hip and knee replacements, especially for the stem in hip implants and tibial components in knee implants.
Benefits: Reduced weight makes them easier on the surrounding bone and tissue.
Drawbacks:: Generally more expensive than other metals and slightly less wear-resistant than cobalt-chromium.
Polyethylene
Ultra-High Molecular Weight Polyethylene (UHMWPE)
Properties: Highly durable plastic with good wear resistance.
Usage: Commonly used for the acetabular component in hip replacements and for the tibial plateau and sometimes the patellar component in knee replacements.
Benefits: Reduces friction between the metal components, minimizing wear.
Drawbacks: Earlier versions were prone to wear and could cause osteolysis; however, modern, highly cross-linked UHMWPE has significantly improved wear characteristics.
Ceramics
Alumina and Zirconia
Properties: Extremely hard, smooth, and wear-resistant, with excellent biocompatibility.
Usage: Mainly used in hip replacements for both the femoral head and the acetabular liner. Less commonly used in knee replacements due to load considerations.
Benefits: Virtually eliminates the risk of metal ion release and significantly reduces wear.
Drawbacks: Ceramic components can be brittle and may fracture under severe impact.
Composite Materials
Carbon Fiber-Reinforced Polyethylene
Combines the wear resistance of carbon fiber with the durability of polyethylene.
Used in both hip and knee replacements to enhance the strength and longevity of the components.
Offers improved wear characteristics over standard polyethylene.
Still relatively new, so long-term outcomes and performance are not as well documented as other materials.
