Enhanced strength in cemented stem fixation using adhesive acrylic cement as a metal coating material

Area of Science:

• Biomaterials Engineering
• Orthopedic Surgery
• Materials Science

Background:

• Aseptic loosening of cemented total hip arthroplasty is often caused by mechanical weakness at the metal stem-bone cement interface.
• Existing acrylic bone cements have limitations in achieving optimal bond strength with metal implants.

Purpose of the Study:

• To evaluate the efficacy of an adhesive acrylic bone cement containing 4-methacryloyloxyethyl trimellitate anhydride (4-META) as a metal coating.
• To enhance the mechanical strength and durability of cemented fixation in total hip arthroplasty.

Main Methods:

• Application of 4-META containing acrylic bone cement as a coating material on metal substrates (SUS-304 and titanium alloy).
• Measurement of tensile bond strength between the coated metal and bone cement compared to commercial acrylic bone cement.
• Assessment of shear strength of coated and uncoated metal implants fixed with bone cement, including evaluation after saline immersion.

Main Results:

• The 4-META bone cement demonstrated 2-3 times greater tensile bond strength to metals compared to conventional acrylic bone cement.
• Shear strength of coated metals was significantly higher (approx. 4x for SUS-304, 3x for Ti alloy) than uncoated metals.
• The enhanced shear strength remained stable after 1 week of saline immersion, indicating good durability.

Conclusions:

• Coating metal stems with 4-META bone cement substantially increases fixation strength and durability.
• The room-temperature application process allows for intraoperative coating of metal stems.
• This technique holds potential for improving the long-term success and reducing aseptic loosening in total hip arthroplasty.