Quiz Question
In Sisk 2024 et al., which IMN design improvement addresses rotational slack?
🔍 Key Findings Summary
- IMN provides relative stability, resists bending/torsion due to central axis alignment
- Larger diameter nails = exponentially greater stiffness (∝ D⁴)
- Trade-off: Larger interlocking holes weaken fatigue strength of the nail
- Reaming increases contact/stability but has pros/cons:
- Improves outcomes in closed fractures
- May reduce endosteal blood flow in thin-walled bones (e.g., cats)
- Design advances:
- Angle-stable IMN reduce rotational slack
- Expandable nails simplify insertion but may compromise removal or compressive load resistance
- Precontoured nails match bone curvature but lack consistent clinical superiority
- Material debates continue (e.g., titanium vs. stainless steel vs. magnesium)
Veterinary and Comparative Orthopedics and Traumatology
6
2024
Biomechanical Principles of Intramedullary Nails in Veterinary and Human Medicine
2024-6-VCOT-sisk-4
In Trefny 2025 et al., on plate length and stiffness, what plate–bone ratio was required before significant stiffness and strain differences became apparent?
🔍 Key Findings
- 12-hole LCPs (80% plate–bone ratio) showed significantly higher construct stiffness than 6-, 8-, or 10-hole plates in both compression and tension bending.
- Strain on the plate was significantly lower in 12-hole vs 6-hole plates at all regions of interest (ROIs), especially around the fracture gap.
- No incremental increases in stiffness or decreases in strain were observed between 6-, 8-, and 10-hole plates—only when comparing to 12-hole plates.
- Bone model strain adjacent to the plate end was significantly lower for 10- and 12-hole plates vs 6-hole plates under both loading conditions.
- The threshold effect suggests biomechanical benefits only emerge beyond a plate–bone ratio of ~80%.
- Working length increased from 9.4 mm (6-hole) to 13 mm (others), potentially influencing strain/stiffness differences.
- Four-point bending was used, as it replicates the most biomechanically relevant force on plated long bones.
- Clinical implication: Longer plates may reduce plate strain and peri-implant bone strain, potentially lowering risk of fatigue failure or stress risers.
Veterinary and Comparative Orthopaedics and Traumatology
2
2025
Effect of Plate Length on Construct Stiffness and Strain in a Synthetic Short-Fragment Fracture Gap Model Stabilized with a 3.5-mm Locking Compression Plate
2025-2-VCOT-trefny-5
In Wood 2024 et al., on knot security and locking throws, which suture material showed greater holding strength?
🔍 Key Findings
- Adding a single locking throw significantly increased holding security for specific knots, including the surgeon's throw (p = .0001) and square throw (p = .0002).
- For the Miller's throw (p = .166) and strangle throw (p = .808), no significant improvement was observed with a locking throw.
- After locking throw addition, all five knots leaked at similar pressures (p = .5233), and these pressures exceeded physiologic arterial pressures.
- Surgeon's throw without a locking throw had the lowest leak pressure (62.5 ± 46.2 mm Hg), below physiologic arterial values.
- The square throw without locking also leaked below physiologic pressures (148.7 ± 109.4 mm Hg), though it outperformed the surgeon's throw.
- Miller’s and strangle throws performed significantly better than square or surgeon’s throws without locking, achieving leak pressures >200 mm Hg.
- All knots used 2-0 polyglyconate monofilament (Maxon); no comparisons across suture types or sizes were performed.
- Authors concluded that correct tensioning and locking throw addition are key to safe vascular ligation. Miller’s, strangle, or slip knots are preferred for challenging surgical fields.
Veterinary Surgery
4
2024
Influence of a single locking throw on the in vitro holding security of five friction knots using two monofilament suture materials in a canine model
2024-4-VS-wood-4
In Lu 2025 et al., on SOP constructs, what was the effect of bending tees on **craniocaudal bending stiffness**?
🔍 Key Findings
- Bending tees significantly increased mediolateral bending stiffness, but not craniocaudal stiffness, in plate-bone constructs.
- Mean mediolateral stiffness was 43.2 N/mm with tees vs. 41.1 N/mm without (p = 0.0042), though the absolute difference was small.
- No significant differences were found in craniocaudal bending stiffness between constructs with or without tees (p = 0.89).
- Plastic deformation occurred in all constructs; no screw pull-out or implant breakage was observed.
- SOP nodes may resist compressive but not tensile deformation, suggesting variable mechanical contributions depending on loading direction.
- Craniocaudal bending had greater stiffness than mediolateral due to higher area moment of inertia along the node diameter.
- Clinical relevance of added stiffness from tees remains unclear, warranting further in vivo and cyclic testing.
- This was the first study to directly test SOP constructs with/without tees over a fracture gap in multiple planes.
Veterinary and Comparative Orthopaedics and Traumatology
2
2025
Comparison of Bending Stiffness between String of Pearls Plate-Bone Substitute Constructs with and without Bending Tees in a Fracture Gap Model
2025-2-VCOT-lu-1
In Gutbrod 2024 et al., on feline tibial stabilization, what intramedullary pin diameter was associated with the highest biomechanical performance?
🔍 Key Findings
- 2.4 mm LCP with a 1.6 mm IM pin had the highest axial stiffness and yield strength among the tested constructs.
- Axial stiffness was significantly higher in the 2.4 mm LCP + 1.6 mm IM pin group compared to 2.7 mm LCP alone (p = .013).
- No significant difference in torsional stiffness was found among groups.
- 2.4 mm LCP + 1.0 mm pin had the lowest stiffness and failure load, underperforming both other constructs.
- All constructs failed via valgus bending, consistent with clinical observations in feline tibial fractures.
- A 1.6 mm pin (~50% canal fill) resulted in superior construct performance vs. 1.0 mm (~30% fill).
- Group 2 (2.4 LCP + 1.6 mm pin) outperformed the 2.7 mm LCP alone in stiffness, despite using a smaller plate.
- Plate–rod constructs may better preserve periosteal blood supply and support minimally invasive stabilization strategies.
Veterinary Surgery
4
2024
Ex vivo biomechanical evaluation of 2.4 mm LCP plate rod constructs versus 2.7 mm LCP applied to the feline tibia
2024-4-VS-gutbrod-3
In Townsend 2024 et al., on 3D osteotomy accuracy, which metric did NOT differ significantly between PSG and freehand methods?
🔍 Key Findings:
- Design: Ex vivo study with 24 paired limbs from normal beagle dogs.
- Osteotomy types (3 groups):
- 30° uniplanar frontal wedge
- Oblique (30° frontal, 15° sagittal)
- Single oblique (30° frontal, 15° sagittal, 30° external rotation)
- Comparison: 3D PSG vs Freehand (FH)
- Main Outcomes:
- PSG accuracy: Mean angular deviation = 2.8° vs 6.4° in FH (p < .001).
- 84% of PSG osteotomies were within 5° of target vs 50% of FH.
- Significant improvements with PSG in:
- Group 1 (uniplanar frontal) proximal and distal frontal planes (p < .001, .006)
- Group 3 (SOO) frontal and sagittal planes (p = .002, .043)
- Time: PSG faster in complex SOO group (84s vs 162s, p < .001); no difference in others.
- No difference in osteotomy location (mm) between methods.
- Clinical relevance: PSG more consistent and accurate, especially for complex cuts.
Veterinary Surgery
2
2024
Comparison of three-dimensional printed patient-specific guides versus freehand approach for radial osteotomies in normal dogs: Ex vivo model
2024-2-VS-townsend-5
In Trefny 2025 et al., on locking plate biomechanics, when did transcortical contact occur in long working length constructs?
🔍 Key Findings
- Short working length constructs had significantly higher stiffness and lower strain than long constructs in compression bending (p = 0.0172).
- In tension bending, short constructs also had higher precontact stiffness and lower strain, but this reversed after transcortical contact (~150 N).
- Transcortical contact increased stiffness only in long constructs, producing a bilinear load-displacement curve.
- Postcontact stiffness was higher in long constructs, but this may not reflect clinical benefit due to risks of high interfragmentary strain.
- Short working length reduced strain at multiple ROIs under both loading conditions, including over fracture gap (Tables 1–3).
- Increased working length promoted stress concentration and deformation, especially in compression bending.
- In vitro benefits of long constructs (via contact stability) may not translate to healing, as repetitive loading could increase plate strain and bone resorption.
- Plate strain was effectively mapped using 3D digital image correlation, confirming regional strain differences between configurations.
Veterinary and Comparative Orthopaedics and Traumatology
3
2025
Effect of Plate Screw Configuration on Construct Stiffness and Plate Strain in a Synthetic Short Fragment Small Gap Fracture Model Stabilized with a 12-Hole 3.5-mm Locking Compression Plate
2025-3-VCOT-trefny-2
In Perez Neto 2025 et al., on hip resurfacing arthroplasty, approximately how many times body weight did prosthetic femurs withstand before failure?
🔍 Key Findings
- In an ex vivo study of 20 canine femur pairs, implantation of a novel hip resurfacing arthroplasty (HRA) prosthesis reduced maximum load (ML) by 22% and load at collapse (LC) by 27% vs. intact controls (p ≤ 0.05).
- Displacement at maximum load (DML), displacement at collapse (DC), and stiffness (k) were not significantly different between prosthesis and control groups.
- Both groups showed similar failure patterns, with 92% failing at the femoral neck.
- All prosthetic femurs still withstood ~6.2× body weight — exceeding estimated in vivo peak loads (~1.64× BW).
- Prosthesis positioning (neutral vs valgus) had no significant effect on biomechanical outcomes.
- Implant design preserved more metaphyseal bone stock than total hip replacement, possibly explaining the smaller load reduction compared to other short-stem prostheses.
- The press-fit cobalt–chromium design with conical stem allowed full contact and stress distribution over the femoral head/neck.
- Authors conclude the device has adequate immediate biomechanical strength for clinical use, though long-term in vivo studies are needed.
Veterinary and Comparative Orthopaedics and Traumatology
4
2025
Biomechanical Evaluation of a Femoral Implant for Hip Resurfacing Arthroplasty in Dogs: An Ex Vivo Study
2025-4-VCOT-perezneto-4
In Sisk 2024 et al., which nail design feature may reduce infection risk?
🔍 Key Findings Summary
- IMN provides relative stability, resists bending/torsion due to central axis alignment
- Larger diameter nails = exponentially greater stiffness (∝ D⁴)
- Trade-off: Larger interlocking holes weaken fatigue strength of the nail
- Reaming increases contact/stability but has pros/cons:
- Improves outcomes in closed fractures
- May reduce endosteal blood flow in thin-walled bones (e.g., cats)
- Design advances:
- Angle-stable IMN reduce rotational slack
- Expandable nails simplify insertion but may compromise removal or compressive load resistance
- Precontoured nails match bone curvature but lack consistent clinical superiority
- Material debates continue (e.g., titanium vs. stainless steel vs. magnesium)
Veterinary and Comparative Orthopedics and Traumatology
6
2024
Biomechanical Principles of Intramedullary Nails in Veterinary and Human Medicine
2024-6-VCOT-sisk-2
In Hawker 2025 et al., on locking head inserts, what effect did LHI have on axial stiffness and displacement?
🔍 Key Findings
- Adding Locking Head Inserts (LHI) to a 3.5-mm LCP had no effect on plate strain, stiffness, or deformation in an open fracture gap model.
- Peak strain consistently occurred at the Combi-hole over the fracture gap, with values up to ~1837 µε.
- No significant difference in strain was found across configurations with 0, 3, or 9 LHI (p = 0.847).
- Construct stiffness and compressive displacement also remained unchanged regardless of LHI count (p = 0.311 and 0.069 respectively).
- Study contradicted the hypothesis that LHI would reduce strain and increase stiffness under biologic loading.
- Combi-hole design may limit the efficacy of LHI, as LHI only fill the locking portion, not the compression side where strain peaks.
- Implant fatigue risk remains highest over unfilled screw holes, especially over fracture sites—confirming previous failure patterns.
- Surgeons should consider alternative methods to reduce strain when facing high implant load scenarios.
Veterinary and Comparative Orthopaedics and Traumatology
4
2025
The Effect of Locking Head Inserts on the Biomechanical Properties of a 3.5-mm Broad Locking Compression Plate When Used in an Open Fracture-Gap Model
2025-4-VCOT-hawker-3
Quiz Results
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Key Findings