Modified PMMA cements for a hydrolysis resistant metal-polymer interface in orthopaedic applications

Area of Science:

• Biomaterials Engineering
• Orthopedic Surgery
• Materials Science

Background:

• The interface between metal implants and bone cement is a critical factor in cemented hip prosthesis longevity.
• Failure at this interface, due to mechanical or hydrolytic degradation, can lead to osteolysis and implant loosening.
• Current methods for improving interface stability are often complex or compromise cement properties.

Purpose of the Study:

• To enhance the hydrolysis resistance of the titanium-bone cement interface.
• To evaluate the effect of cement modification using a bifunctional coupling agent on interface stability.
• To assess the impact of this modification on the mechanical properties of the bone cement.

Main Methods:

• Bone cement (PMMA) was modified by adding methacryloxypropyl-trimethoxysilane (5-20 wt.%) as a bifunctional coupling agent.
• The shear bond strength of PMMA/titanium joints was tested before and after aging in physiological saline.
• Mechanical properties (compressive and bending strength) of the modified cement were evaluated.

Main Results:

• Cement modification significantly improved the hydrolysis resistance of the titanium-PMMA interface.
• The addition of the coupling agent did not negatively alter the mechanical properties of the bone cement.
• The proposed modification offers a clinically applicable method for improving implant stability.

Conclusions:

• Modification of bone cement with a bifunctional coupling agent is an effective strategy to improve the hydrolysis resistance of the titanium-bone cement interface.
• This approach maintains the essential mechanical characteristics of the cement, crucial for clinical use.
• The easy applicability of this cement modification technique supports its potential for enhancing the long-term success of cemented hip prostheses.