Fixed-angle screws vs standard screws in acetabular prosthesis fixation: a cadaveric biomechanical study

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Implant Biomechanics

Background:

• Achieving secure fixation of acetabular components is a critical challenge in total hip arthroplasty (THA).
• Suboptimal fixation can lead to component loosening and revision surgery.
• Novel fixation methods are needed to enhance implant stability.

Purpose of the Study:

• To biomechanically analyze and compare the fixation strength of acetabular components using fixed-angle screws versus standard cancellous screws.
• To evaluate the influence of screw configuration on fixation stability under cyclic and load-to-failure conditions.

Main Methods:

• Multihole, porous-backed acetabular prostheses were implanted in 8 cadaveric pelves using press-fit techniques.
• Fixed-angle screws were applied to the left acetabuli, and standard cancellous screws to the right.
• Biomechanical testing included subfailure cyclic loading and load-to-failure analysis.

Main Results:

• Fixed-angle screws demonstrated substantially enhanced acetabular fixation strength under both cyclic loading and load-to-failure conditions.
• A triradiate screw configuration with fixed-angle screws significantly increased the bending moment required to cause failure.
• The fixed-angle screw group exhibited superior stability compared to the standard screw group.

Conclusions:

• Fixed-angle screws provide significantly improved biomechanical fixation for acetabular prostheses in THA.
• This fixation method offers enhanced stability, particularly in challenging clinical scenarios requiring rigid component support.
• Fixed-angle screws represent a promising advancement for achieving robust acetabular component fixation.