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

OBJECTIVE

To evaluate an arthroscopic indentation instrument (Artscan 200) for assessment of the health status of equine articular cartilage.

STUDY DESIGN

In vitro experiment using equine isolated proximal phalanx (P1) specimens.

SAMPLE POPULATION

P1 specimens from 39 horses (aged 1.5-22 years).

METHODS

Reproducibility was tested by determination of the coefficient of variation (CV). Dynamic modulus and cartilage degeneration index (CDI) values were measured at 2 predefined sites (site 1, joint margin; site 2, joint center) to assess the accuracy and to evaluate the relation with surface integrity.

RESULTS

CV was 9.0%. A significant decrease in indenter force was identified when dynamic modulus values decreased to <2.5 MPa (range of tested samples 0.9-8.1 MPa) and when CDI values at site 1 increased to >50% (range 5.4-72.8%).

CONCLUSIONS

Technique reproducibility was adequate but accuracy was limited. The device identified degeneration-associated decreases in cartilage stiffness only when the mechanical properties of the cartilage were considerably changed.

CLINICAL RELEVANCE

Usefulness of this indentation instrument during arthroscopic surgery would be limited in the initial phase of OA-like cartilage degeneration, but may yield important information in more advanced OA.