Pre-coated orthopedic implants with bone cement.

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Medical Device Engineering

Background:

• Bone cement fixation is crucial for orthopedic implants.
• Conventional methods can lead to complications like shrinkage and monomer release.
• Improving implant-bone interfacial strength is a key goal in orthopedic research.

Purpose of the Study:

• To assess the feasibility and efficacy of pre-coating bone implants with acrylic bone cement.
• To evaluate the impact of pre-coating on interfacial shear strength in vitro and in vivo.
• To compare pre-coated implants with conventional methods regarding mechanical properties and potential surgical benefits.

Main Methods:

• Four implant types were tested: canine femoral prosthesis, polished steel rod (with/without pre-coating), and sandblasted steel rod (pre-coated).
• Implants were inserted into canine femurs for in vitro and in vivo testing.
• Push-out tests were performed on serial sections to measure interfacial shear strengths (cement-bone-implant).

Main Results:

• Pre-coating significantly increased rod/cement interfacial shear strength, especially with sandblasting (6.84 MPa vs. 0.5 MPa for polished).
• Bone/cement interfacial strength was 1.17 MPa (in vitro) and 1.68 MPa (in vivo).
• Microscopic analysis revealed reduced gaps with pre-coated implants, suggesting less shrinkage.

Conclusions:

• Pre-coating bone implants with acrylic bone cement enhances interfacial strength and reduces gaps.
• Pre-coating may lower setting temperature, shrinkage, and monomer release during surgery.
• This technique offers potential advantages over conventional cement fixation, including gradual load transmission and auto-centering.