An in vitro biomechanical comparison of the breaking strength and stiffness of polydioxanone (sizes 2, 7) and polyglactin 910 (sizes 3, 6) in the equine linea alba.
Authors: Fierheller Erin E, Wilson David G
Journal: Veterinary surgery : VS
Summary
Abdominal wall closure remains a critical consideration in equine surgical practice, yet comparative data on suture performance in linea alba repair have been limited. Fierheller and Wilson tested four suture constructs—polydioxanone sizes 2 and 7 (PD) and polyglactin 910 sizes 3 and 6 (PG)—using fresh linea alba tissue harvested from 12 horses and subjected to single-cycle tensile loading at 100 mm/min until failure. Size 7 polydioxanone demonstrated superior breaking strength at 316.8 N, substantially outperforming size 2 polydioxanone (193.0 N) and both polyglactin materials; however, size 6 polyglactin exhibited the highest stiffness (14 N/mm), which may influence load distribution differently during healing. Critically, suture material itself consistently failed before linea alba tissue in 94 of 96 specimens, with 90.4% of failures occurring adjacent to the knot, indicating that knot security and suture calibre are the limiting factors rather than tissue integrity. For practitioners prioritising immediate post-operative strength during the critical early healing phase, size 7 polydioxanone offers the optimal balance of breaking strength and proven in vivo longevity, though the superior stiffness of size 6 polyglactin warrants consideration where load distribution properties may be advantageous.
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Practical Takeaways
- •Use size 7 polydioxanone for equine linea alba closure when maximum initial strength is needed, as it provides the best breaking strength profile in this tissue
- •Avoid undersized sutures (size 2) for abdominal wall closure in horses, as they have significantly lower failure strength (193 N vs 316.8 N) with no biomechanical advantage
- •Pay particular attention to knot placement and technique, as 90% of failures occur at the knot—proper knot security is the critical variable in closure longevity
Key Findings
- •Size 7 polydioxanone had the highest breaking strength at 316.8 N, significantly outperforming smaller suture sizes across both material types
- •Larger suture materials demonstrated both higher breaking strength and greater stiffness, with size 6 polyglactin 910 achieving 14 N/mm stiffness
- •Suture material failed in 94 of 96 specimens rather than linea alba tissue, indicating suture selection is the critical failure variable
- •90.4% of suture loop failures occurred adjacent to the knot, identifying a consistent weak point in closure techniques