In Vitro Biomechanical Study of Meniscal Properties in Patients with Severe Knee Osteoarthritis

Yuqi Liu¹Songhua Yan¹Haixia Zhang¹Jizhou Zeng^2*Kuan Zhang^1*

• ¹Capital Medical University, Beijing, China
• ²Beijing Luhe Hospital Affiliated to Capital Medical University, Beijing, China

The meniscus is an important component of the human knee joint, and meniscal injury can lead to knee joint pathology, eventually resulting in knee osteoarthritis (KOA). Quantifying the biomechanical properties of the meniscus is essential in understanding its contribution to knee joint function and knee joint biomechanics. This study was designed to determine the biomechanical properties of the meniscus in patients with severe KOA through biomechanical experiments, and the inverse finite element analysis (iFEA) model. The meniscus was collected from patients, graded, and then subjected to tensile (n=113) and compressive testing (n=137). The iFEA model was then developed to estimate the biomechanical properties of the meniscus using experimental data and optimization algorithms. In patients with severe KOA, the average tensile modulus of the lateral meniscus (57.9 ± 34.1 MPa) increased by approximately 40.5% compared with that of the medial meniscus (41.2 ± 28.8 MPa). At the 10% strain level, the average compressive modulus was 2.2 ± 1.5 MPa for the medial meniscus, and 2.5 ± 1.5 MPa for the lateral meniscus. At the 20% strain level, compared with the 10% strain level, the average compressive modulus of the medial meniscus increased by approximately 54.5%, while that of the lateral meniscus increased by 136%. At the 30% strain level, the average compressive modulus of the medial meniscus increased by approximately 222.7%, and that of the lateral meniscus increased by 288%, compared with the 10% strain level. The tensile modulus as well as the compressive modulus of the meniscus show a stepwise decrease with increasing degeneration. The mechanical properties of the meniscus reported in the literature, which are frequently referenced, are significantly different from those in patients with severe KOA, so caution should be taken when applying the mechanical properties of the meniscus in the literature for modeling and simulations. The iFEA model, developed with a Mooney-Rivlin hyperelastic material formulation for the meniscus in severe KOA patients demonstrated a high goodness of fit (R² > 0.9). This suggests that iFEA is promising approach for predicting constitutive parameters across different degeneration levels and meniscal regions.