Assessment of Human Articular Cartilage Issued from Asymptomatic & TKR Donors

Introduction: Cartilage degeneration is a progressive process and currently, only end-stage surgical treatments such as total knee replacement (TKR) lead to an improved condition. To prevent or delay this surgery, several less invasive alternatives could be considered, such as pharmacological treatments, scaffolds and partial replacements1. However, current diagnostic techniques are limited and a diagnostic tool capable of providing predictive value for disease progression in the early and potentially reversible stages is urgently needed. The Arthro-BST, a technology nearing clinical application overcomes these limitations by offering a specific and sensitive electromechanical parameter (Quantitative parameter QP) that reflects cartilage integrity. The current study shows the potential of this technique for the characterization of cartilage integrity across the entire articular surface providing a new assessment and diagnostic parameter (DP) that allows the classification of cartilage in three ranges: ‘normal’, ‘degenerated’ and ‘abnormally thin and degenerated’.

Materials and Methods: Two age-matched groups of 8 asymptomatic (where the average was considered as a reference once the degraded regions are removed) and 2 TKR human tibial plateaus (TP) have been mapped ex vivo using the Arthro-BST (Biomomentum Inc.) in order to assess electromechanical properties. To validate these measurements, the instantaneous modulus (IM) and thickness were also mapped through an automated indentation and thickness technique with the Mach-1 mechanical tester (v500css, Biomomentum Inc.). Samples from each group were compared to the reference and a diagnostic parameter (DP) was calculated as the difference between the measured parameter and the reference parameter at the same location for QP, IM and thickness.

Results and Discussion: Mapping of electromechanical QP, thickness and IM revealed significant spatial variation between asymptomatic and TKR samples. Based on the diagnostic parameter (DP), different stages of degeneration were defined (Fig.1). From asymptomatic to TKR samples, electromechanical-DP and IM-DP revealed a transition from normally to degenerated and then to abnormally thin/degenerated cartilage. As for the

thickness, the cartilage becomes thicker but then thinner at later-stage in the TKR cartilage.

Conclusions: The potential of Arthro-BST for the assessment of asymptomatic and TKR cartilage in human samples was highlighted and validated with the mechanical and thickness measurements. The DP revealed an ability to distinguish between the different stages of degeneration.