Tensile Properties of Ligament and Tendon Structures in the Human Knee: An Exploratory Study

Background: Injuries to the knee joint usually involve ligament or tendon structures. Most of these injuries are traumatic in origin. To better understand the structures and the associated failure mechanisms, a specific understanding of the biomechanical properties of the individual structures is necessary. Objectives: The aim of this study was to biomechanically analyze the tendon and ligament structures around the knee joint in order to acquire tissue-specific mechanical characteristics of these anatomical structures. Methods: Five knee joints (fresh frozen) from three donors were thawed over the course of three days. The respective ligaments and tendons of the knee were separated, removed and cut into a dogbone shape for uniaxial tensile tests. The specimens were clamped in the testing machine using 3D-printed specimen holders. Results: A total of 57 samples from 15 different ligaments and tendons were successfully tested. The tensile strengths were in the range of 0.67–67.99 MPa (patellar tendon vs. biceps femoris tendon) and the moduli of elasticity between 2.1 and 316.9 MPa. A range of 6.2–47.2% was determined for the failure strains. Similar fluctuation ranges were also found in intra-individual comparisons. Conclusions: The results show a clear tissue-specific variation in the strength and elastic modulus.