Iliotibial band stiffness is associated with patellar height

Increased patellar height (i.e., patella alta) is associated with patellar instability, patellofemoral pain, and cartilage lesions. Despite its importance, the relationship between patellar height and soft-tissue stiffness remains unclear, which this study aimed to investigate. Twenty-two young participants (11 females; age 26.1 ± 3.8 years) were recruited for this study. The shear elastic moduli of the rectus femoris, vastus lateralis, vastus medialis, lateral patellofemoral ligament, medial patellofemoral ligament, and iliotibial band (ITB) were measured using shear wave elastography as indices of soft-tissue stiffness, and Insall-Salvati ratio (ISR) and Patellotrochlear index (PTI) were measured using magnetic resonance imaging as indices of patellar height in the knee extended position. To evaluate the relationship between patellar height and soft-tissue stiffness, single regression analyses were performed with patellar height as the dependent variable and soft-tissue stiffness as the independent variable. The single regression analysis showed that the shear elastic modulus of ITB was significantly associated with both ISR and PTI (β = 0.58 and -0.53, respectively), however, other soft-tissues were not associated with either ISR or PTI. These findings indicate that patellar height increases with ITB stiffness, which suggests the possibility that decreasing ITB stiffness by means such as stretching, may decrease patellar height.