Background: The fibrous mediopatellar plica can cause high contact pressure on the adjacent articular cartilage and lead to its degeneration. The purpose of this study was to investigate the biomechanical properties of the plica and to correlate this with the plica's fiber content and patients' ages.
Methods: An experimental study on the tensile strength of the mediopatellar plica was conducted using high precision micro-force tensile tests. These tests were undertaken on plica specimens taken from 50 knees of patients with different ages. The force-deflection curves resulting from these tests were recorded and transferred to stress-stain curves to obtain the Young's moduli of these specimens. In addition, pathological tissue dyeing tests were used to assess the fiber content ratio of each specimen. The relationship of the Young's moduli of these specimens with the severity of their pathologic change was also evaluated.
Findings: The Young's modulus of the plica was found to be ranging from 10 to 110 MPa. It has positive correlation with patient's age. The relationship between the fiber content ratio and Young's modulus can be fitted properly using a quadratic regression model. The Young's modulus of the plica was also positively correlated with the severity of its pathologic change.
Interpretation: The test results indicated that as patients get older, the fiber content of the mediopatellar plica and the Young's modulus of the plica will increase accordingly. We also demonstrated that the Young's modulus of the medial plica was positively correlated with the severity of the plica lesion.