A new device to detect early cartilage degeneration

BACKGROUND: Currently available arthroscopic techniques do not allow the quantification of cartilage stiffness without direct mechanical indentation or penetration of the tissue. PURPOSE: A novel device, capable of quantifying cartilage stiffness during arthroscopy, is believed to detect degenerated cartilage. STUDY DESIGN: Controlled laboratory study. METHODS: The stiffness of biological materials was measured arthroscopically without contact between the instrument and the examined object. Object deformation was produced by a flow of sodium chloride and measured optically. Eight ovine femoral condyles and tibial plateaus were tested in a native and degenerated (0.1% trypsin solution) state. Cartilage stiffness was nondestructively determined by using the new device and by indentation methods. In addition, a standard probe was measured by 5 independent users. RESULTS: The trypsin caused cartilage degeneration and consequently stiffness reduction, measured at 30.8% by the new device and 33.0% by indentation. A good correlation (r = 0.69) between the new device and the standard indentation procedure was observed. Intraindividual and interindividual variability of the new device were low (<10%). CONCLUSIONS: The developed device has demonstrated the ability to quantify the mechanical quality of cartilage by means of mechanical stiffness measurements. Clinical Relevance: The findings suggest that this device has the capability to detect cartilage degeneration at an early stage.