An in vitro biomechanical investigation of the mechanical properties of dynamic compression plated osteotomized adult equine tibiae.

The research investigated the strength of adult horse tibia bones that had been repaired with dynamic compression plates by comparing them to unbroken tibia bones. The testing involved examining the bone’s resistance to pressure, bending, and twisting. The results showed that while the repaired bones could handle post-operative pressure and bending reasonably well, they may not be strong enough to resist twisting during immediate post-operation weight bearing at a walk.

Methodology

• The scientists used 12 pairs of adult horse tibia bones for the study.
• They broke (osteotomized) some of the bones then repaired them using two dynamic compression plates (DCP). These acted as models of surgically repaired bones.
• Other bones were left intact to act as a comparison.
• Both the repaired tibiae and the intact ones had pressure (compression), bending, and twisting (torsion) applied to them in a controlled manner until they broke (failed).

Results

• When compared to intact tibiae, the repaired ones performed worse across all testing metrics.
• They had lower yield load, failure load, and stiffness when subjected to compression and torsion.
• Similarly, yield and failure bending moments, and bending stiffness, were lower for the repaired tibiae.
• However, the compression and bending yield loads (the amount of stress the bone can take before it changes shape permanently) were still higher than what would be experienced during normal activity in a horse.
• The amount of torsional load the repaired bones could handle was similar to what would be experienced during a slow walk.

Conclusions

• The researchers concluded that repaired horse tibiae should be strong enough to handle compressive loads and bending moments during immediate postoperative activities.
• Despite this, the repaired bones may not be sturdy enough to resist torsion during slow walking immediately after surgery.
• As a result, the researchers suggest that additional supportive methods may be needed to decrease torsional loads on the bone during recovery from anesthesia and the healing process post surgery.