In vitro biomechanical comparison of a 5-hole 4.5 mm locking compression plate and 5-hole 4.5 mm dynamic compression plate for equine proximal interphalangeal joint arthrodesis.

The research article compares the effectiveness of two types of plates, a locking compression plate (LCP) and a dynamic compression plate (DCP), in equine proximal interphalangeal joint arthrodesis, a procedure on horse forelimbs. The study found that the LCP technique provides greater stability than the DCP technique in a single-cycle, 3-point dorsopalmar bending system.

Research Methodology

• The researchers conducted an experimental mechanical study using six pairs of cadaveric adult equine forelimbs. These cadavers enabled the researchers to evaluate the efficacy of the LCP and DCP techniques without the potential ethical and logistical concerns involved in using live subjects.
• In each pair of forelimbs, one of the proximal interphalangeal (PIP) joints was stabilized with the LCP, while the other was stabilized with the DCP. This allowed the researchers to make direct comparisons between the plates within the same subject, minimising variables.
• The constructs were then put through a single-cycle, 3-point dorsopalmar bending system. This test evaluated how the constructs would behave under bending stress, which mimics the physical stresses that might be encountered in an actual clinical setting.
• The PIP joints were also evaluated with pre- and post-test radiography. This gave visual confirmation of the placement of the plates and any physical changes that may have occurred as a result of the tests.

Findings of the Research

• From the tests, the researchers found that the LCP technique had significantly greater yield load, failure load, and stiffness in comparison to the DCP technique. These characteristics indicate that the LCP provides greater strength and resistance to deformation and breakage.
• However, there was no significant difference between the two constructs in terms of displacement at the yield and failure points. This suggests both plates were comparable in terms of their ability to maintain their original positions under stress.

Conclusion

• The results of this study suggest that, biomechanically, the LCP technique provides significantly greater stability than the DCP technique under the test conditions used in this research. This could have implications for the choice of plating technique in clinical practice, potentially leading to better outcomes for equine patients undergoing proximal interphalangeal joint arthrodesis.