Pre-heating of components in cemented total hip arthroplasty

Area of Science:

• Orthopedic surgery
• Biomaterials science
• Mechanical engineering

Background:

• Septic loosening of cemented femoral components is often caused by fatigue fractures originating at voids in the implant-cement interface.
• Reducing porosity at this interface is crucial for improving implant longevity.
• Component heating is a known method to decrease cement-prosthesis interface porosity.

Purpose of the Study:

• To investigate the effect of heating the femoral component on the implant-cement interface porosity.
• To determine the optimal heating temperature and temperature difference between the implant and bone for reducing porosity.
• To evaluate the synergistic effects of heating and vacuum mixing on interface characteristics.

Main Methods:

• A simulated femoral model was used to study the impact of component heating on the implant-cement interface.
• Intra-operative temperatures of the cement-bone interface were recorded (32.3°C).
• The effect of heating on porosity and microhardness gradients was analyzed.

Main Results:

• Heating the implant synergistically reduces porosity at the implant-cement interface when combined with vacuum mixing.
• Heating reverses microhardness gradients within the cement mantle.
• A minimum temperature difference of 3°C between implant and bone is needed, with 7°C being optimal for porosity reduction while balancing thermal injury risk.

Conclusions:

• Heating the femoral implant significantly reduces interface porosity, a key factor in preventing septic loosening.
• An optimal implant temperature of 40°C is recommended for contemporary cementing techniques to maximize porosity reduction and minimize thermal risks.
• This technique offers a promising strategy for enhancing the stability and longevity of cemented femoral components in hip arthroplasty.