Subscribe to RSS
Optimizing a Critical Gap Femoral Defect Model for Objective Assessment of Bone Regeneration in Dogs
07 August 2019 (online)
Introduction: The objective of this study was to develop a canine nonunion femoral defect model using an angle-stable interlocking nail (AS-ILN) and methods to objectively characterize bone healing.
Materials and Methods: Six healthy hounds (age: 2.5–6.5 year; weight: 23.7–35.5 kg) were treated with unilateral, 4 cm femoral ostectomies, followed by stabilization with an 8 mm AS-ILN. Dogs were randomly assigned to negative or positive control groups (n = 3/group). Positive control defects were treated with autologous cancellous bone graft. Healing was assessed at 0, 6, 12, and 18 weeks with radiography and CT/Mimics 16.0. At 18 weeks, dogs were humanely euthanized. Positive control femurs were biomechanically assessed for torsional stiffness, load to failure, and mode of failure. Histology was performed on both groups. Data were reported as median and range.
Results: The AS-ILN provided appropriate stability without any implant-associated complications. Radiographic healing progressed in 0/3 negative and 3/3 positive control dogs from 0 to 18 weeks. Median bone volume increased from 535 mm3 to 662 mm3 (negative control) versus 1,375 mm3 to 3,999 mm3 (positive control). Median torsional failure load for positive control femurs was 12.0 Nm, versus 42.0 Nm for unoperated contralateral femurs. Histology confirmed nonunion or secondary bone healing.
Discussion/Conclusion: When paired with the described outcome measures, use of an AS-ILN represents an advance in large animal bone regeneration models and accomplishes “refinement” and “reduction” goals of humane animal research.
Acknowledgment: No proprietary interest. Funded by the Texas A&M Health Science Center and the Bone & Joint fund.