Related Experiment Video
Updated: Jun 28, 2025
A Probing Device for Quantitatively Measuring the Mechanical Properties of Soft Tissues during Arthroscopy
Published on: May 1, 2020
Laser-irradiating infrared attenuated total reflection spectroscopy of articular cartilage: Potential and challenges
P Krebs1, M Nägele2, P Fomina1
1Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany.
Objective:
A prototype infrared attenuated total reflection (IR-ATR) laser spectroscopic system designed for in vivo classification of human cartilage tissue according to its histological health status during arthroscopic surgery is presented. Prior to real-world in vivo applications, this so-called osteoarthritis (OA) scanner has been tested at in vitro conditions revealing the challenges associated with complex sample matrices and the accordingly obtained sparse spectral datasets.
Methods:
In vitro studies on human knee cartilage samples at different contact pressures (i.e., 0.2-0.5 MPa) allowed recording cartilage degeneration characteristic IR signatures comparable to in vivo conditions with high temporal resolution. Afterwards, the cartilage samples were assessed based on the clinically acknowledged osteoarthritis cartilage histopathology assessment (OARSI) system and correlated with the obtained sparse IR data.
Results:
Amide and carbohydrate signal behavior was observed to be almost identical between the obtained sparse IR data and previously measured FTIR data used for sparse partial least squares discriminant analysis (SPLSDA) to identify the spectral regions relevant to cartilage condition. Contact pressures between 0.3 and 0.4 MPa seem to provide the best sparse IR spectra for cylindrical (d = 3 mm) probe tips.
Conclusion:
Laser-irradiating IR-ATR spectroscopy is a promising analytical technique for future arthroscopic applications to differentiate healthy and osteoarthritic cartilage tissue. However, this study also revealed that the flexible connection between the laser-based analyzer and the arthroscopic ATR-probe via IR-transparent fiberoptic cables may affect the robustness of the obtained IR data and requires further improvements.
