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Caldeira et al: In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
Veterinary and Comparative Orthopedics and Traumatology 1, 2025

🔍 Key Findings

Design: In vitro study on cadaveric femurs (n=21) with basilar femoral neck fractures stabilized using 2 vs 3 titanium cannulated screws.

Stiffness: Control > 3-screw > 2-screw (674 > 120 > 90 N/mm).

Yield Load: 3-screw (586 N) > 2-screw (303 N); both < intact femur (2692 N).

Displacement: No difference across groups.

Complication: 3-screw technique more demanding; higher risk of cortical perforation, especially with narrow femoral necks.

Failure Mode: Dislodgement of femoral head + screw shaft bending.

Conclusion: 3 screws = stronger construct than 2 screws. Clinical implications need further study.

In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs

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← Articles

Caldeira et al: In Vitro Biomechanical Study of Femoral Neck Fracture Fixation with Two or Three Cannulated Screws in Dogs
Veterinary and Comparative Orthopedics and Traumatology 1, 2025

🔍 Key Findings

Design: In vitro study on cadaveric femurs (n=21) with basilar femoral neck fractures stabilized using 2 vs 3 titanium cannulated screws.

Stiffness: Control > 3-screw > 2-screw (674 > 120 > 90 N/mm).

Yield Load: 3-screw (586 N) > 2-screw (303 N); both < intact femur (2692 N).

Displacement: No difference across groups.

Complication: 3-screw technique more demanding; higher risk of cortical perforation, especially with narrow femoral necks.

Failure Mode: Dislodgement of femoral head + screw shaft bending.

Conclusion: 3 screws = stronger construct than 2 screws. Clinical implications need further study.

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Multiple Choice Questions on this study

In Caldeira 2025 et al., on femoral neck fixation, what was the main mechanical advantage of using three cannulated screws over two?

A. Increased stiffness
B. Reduced displacement
C. Decreased surgical time
D. Higher yield load
E. Lower risk of perforation

Answer: Higher yield load

Explanation: Group 3 (three screws) had significantly higher yield load (586 N) compared to Group 2 (303 N)
In Caldeira 2025 et al., on femoral neck fixation, what complication was more likely with the three-screw construct?

A. Dislodgement of femoral head
B. Screw head fracture
C. Increased risk of cortical perforation
D. Fracture at distal femur
E. Articular cartilage damage

Answer: Increased risk of cortical perforation

Explanation: The three-screw placement had higher risk of cortical bone wall perforation, especially with narrow femoral necks
In Caldeira 2025 et al., on femoral neck fixation, how did displacement values compare among groups?

A. Control group had highest displacement
B. Group 3 had significantly lower displacement
C. Group 2 had highest displacement
D. No significant difference among groups
E. Group 3 had highest displacement

Answer: No significant difference among groups

Explanation: There was no statistically significant difference in displacement between the groups
In Caldeira 2025 et al., on femoral neck fixation, what role did the 3D-printed guide serve?

A. Anchored the femur during testing
B. Created sagittal osteotomy
C. Assisted accurate Kirschner wire placement
D. Simulated load conditions
E. Tightened screws evenly

Answer: Assisted accurate Kirschner wire placement

Explanation: The 3D-printed guide was used to position the guide wires for accurate screw placement
In Caldeira 2025 et al., on femoral neck fixation, which group demonstrated the highest construct stiffness?

A. Two-screw repair
B. Three-screw repair
C. Control (no osteotomy)
D. All groups equal
E. Cannulated + washer combination

Answer: Control (no osteotomy)

Explanation: The intact bones (Group 1) had the highest stiffness (674 N/mm), significantly higher than both fixation groups

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