Tolerance and surface analysis of veterinary bone screws.

Area of Science:

• Veterinary Orthopedics
• Biomaterials Engineering
• Manufacturing Quality Control

Background:

• Human orthopedic implants undergo rigorous quality assessment, but veterinary implants lack comparable standards.
• Dimensional accuracy and surface characteristics are critical for implant function and patient outcomes.

Purpose of the Study:

• To evaluate the dimensional conformity and surface finish of veterinary cortical bone screws.
• To compare veterinary screw quality against established engineering standards.

Main Methods:

• Analysis of 73 veterinary cortical bone screws (2.0 mm) from five manufacturers.
• High-magnification optical microscopy to assess length, diameter, pitch, and thread angle.
• Evaluation against ISO 5835 tolerance limits and a surface finish grading system.

Main Results:

• A high percentage of screws exceeded tolerance limits for all measured dimensions (length, major diameter, minor diameter, pitch, thread angle).
• 40% of screws exhibited unacceptable surface finish.
• Deviations were widespread across all manufacturers, indicating systemic quality issues.

Conclusions:

• Commercially available veterinary bone screws demonstrate significant manufacturing variability and surface defects.
• These quality issues may compromise screw biomechanics and the bone-implant interface.
• The lack of regulatory oversight necessitates enhanced quality control for veterinary orthopedic implants.