Impaction grafted bone chip size effect on initial stability in an acetabular model: Mechanical evaluation

Area of Science:

• Orthopedic Surgery
• Biomaterials Engineering
• Surgical Reconstruction

Background:

• Acetabular bone defects pose challenges in total hip replacement surgery.
• Impaction bone grafting is a successful technique for acetabular reconstruction.
• Initial mechanical stability of bone grafts is crucial for implant survival.

Purpose of the Study:

• To investigate the effect of bone chip size on the initial mechanical stability of acetabular reconstructions.
• To determine the optimal bone chip size for impaction bone grafting in acetabular defect repair.

Main Methods:

• Twenty acetabular models were created, including controls with cemented cups.
• Three groups of acetabular protrusion defects were reconstructed using impaction grafting with 2-4 mm³, 10 mm³, or 20 mm³ bone chip sizes.
• Models underwent compression loading to measure displacement and assess initial mechanical stability.

Main Results:

• Models reconstructed with 10 mm³ bone chips demonstrated superior initial mechanical stability.
• While not statistically significant, 20 mm³ bone chips showed inferior stiffness compared to 10 mm³ chips.
• Smaller bone chips (2-4 mm³) were not explicitly compared for stiffness but implied to be less stable.

Conclusions:

• 10 mm³ bone chips provide the best initial mechanical stability for acetabular reconstruction via impaction grafting.
• The findings challenge the notion that larger bone graft sizes are always superior.
• Optimal bone chip size selection is critical for successful acetabular reconstruction outcomes.