In situ and ex vivo evaluation of an arthroscopic indentation instrument to estimate the health status of articular cartilage in the equine metacarpophalangeal joint.

This study evaluates the practicality and effectiveness of an arthroscopic indentation instrument, specifically the Artscan 200, in determining the health of equine articular cartilage. Although the tool was enough to identify significant decreases in cartilage stiffness due to degeneration, its utility may be limited in the early stages of osteoarthritis (OA)-like cartilage degeneration.

Research Objective and Methodology

• This research aimed to test the effectiveness of the Artscan 200, an arthroscopic indentation instrument, in assessing equine articular cartilage health status.
• Experiments were conducted in vitro using isolated proximal phalanx (P1) specimens from 39 horses aged between 1.5 and 22 years.
• The method’s reproducibility was assessed by determining the coefficient of variation (CV), with a CV of 9.0% indicating good reproducibility.
• The dynamic modulus, a measure of a material’s stiffness, and the Cartilage Degeneration Index (CDI) values were measured at two predefined sites (the joint margin and the center) to assess the tool’s precision and the relationship with the cartilage’s surface integrity.

Research Findings

• The research noted a significant decrease in indenter force, an indicator of cartilage stiffness, when dynamic modulus values fell to less than 2.5 MPa and when CDI values at the joint margin increased to over 50%.
• This finding suggests that the indenter could identify significant decreases in cartilage stiffness associated with degeneration. However, this identification was only possible when the mechanical properties of the cartilage had changed considerably.
• Due to this, the instrument’s accuracy in determining the health of the cartilage was limited, particularly in the early stages of cartilage degeneration resembling OA.

Research Conclusion

• Despite the limitations, the tool could still provide essential information about the more advanced stages of OA, when the mechanical properties of the cartilage have considerably degraded.
• The research, therefore, concludes that while the arthroscopic indentation instrument has some utility, it may not be helpful in identifying the initial stages of OA-like cartilage degeneration.