Porous threaded titanium implant screws have higher insertional torque compared to standard screws

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Materials Science

Background:

• Posterior pelvic ring injuries in the elderly often involve osteoporotic bone, leading to screw back-out and fixation failure.
• Standard cannulated screws may have inadequate purchase in weakened bone.
• Porous threaded titanium implant (PTTI) screws are increasingly used to improve fixation in such cases.

Purpose of the Study:

• To compare the biomechanical fixation profiles of PTTI screws versus standard cannulated screws.
• To assess the insertional torque as a measure of screw purchase in osteoporotic bone surrogates.

Main Methods:

• Fifteen orthopedic trauma surgeons participated in the study.
• Screws were inserted into a validated surrogate for osteoporotic cancellous bone.
• Insertional torque was measured for standard 7.3 mm screws, PTTI screws, and PTTI screws used as rescue screws in pre-drilled holes.

Main Results:

• PTTI screws achieved significantly higher average (2.59x) and maximum (2.99x) insertional torque compared to standard screws (p < 0.001).
• Even as rescue screws, PTTI screws demonstrated substantially greater average (1.99x) and maximum (2.56x) insertional torque (p < 0.001).

Conclusions:

• PTTI screws provide superior initial fixation compared to standard screws in osteoporotic bone models.
• The enhanced insertional torque suggests improved biomechanical stability for PTTI screws in posterior pelvic fixation.
• Further clinical studies are warranted to confirm outcomes and failure rates.