Biomechanical evaluation of peak reverse torque (PRT) in a dynamic compression plate-screw construct used in a goat...

Area of Science:

• Orthopedic biomechanics
• Biomaterials science
• Surgical implantology

Background:

• Peak reverse torque (PRT) quantifies secondary implant stability in healing bone, correlating with osseointegration.
• Secondary stability is vital for bone-implant interface integrity over time.
• PRT measures the force needed to disrupt the bone-implant connection.

Purpose of the Study:

• To compare the peak reverse torque of self-tapping versus non-self-tapping screws in dynamic compression plate constructs.
• To evaluate the influence of screw placement on osseointegration and stability.
• To assess screw stability after 60 days of loading in a goat tibia model.

Main Methods:

• Goat tibiae stabilized with dynamic compression plates and either self-tapping or non-self-tapping screws.
• Screws placed in proximal and distal diaphysis positions.
• Peak reverse torque measured after 60 days of weight-bearing loading.
• Incidence of intracortical fractures during screw placement recorded.

Main Results:

• Screws in the proximal diaphysis exhibited significantly lower peak reverse torque than those in the distal diaphysis.
• Self-tapping screws demonstrated significantly higher peak reverse torque than non-self-tapping screws.
• Non-self-tapping screws were associated with a higher incidence of intracortical fractures during placement.

Conclusions:

• Self-tapping screws offer a more stable bone-implant interface in the initial 60 days of loading compared to non-self-tapping screws.
• This finding is important for orthopedic surgeons and researchers when selecting implants for non-load-sharing fractures requiring stable fixation.
• Consideration of screw type is recommended for optimizing prolonged stability in orthopedic constructs.