A search of 10 unpaired domestic pig knees (Sus scrofa domestica) reveals no incidence of the anterolateral ligament (ALL)

Abstract

The anterolateral ligament (ALL) has been distinctly characterized in the human knee, so there has been a resulting search for animal models with this ligament. Sus scrofa domestica, the domestic pig, has many biomechanical qualities similar to those of human knees, so this study searched for incidence of the ALL in 10 separate specimen knees. The anatomic dissection yielded no identification of an ALL structure in any of the specimens examined. However, the knees did possess other identifiable structures on the anterolateral aspect of the knee, including the lateral collateral ligament (LCL), tibialis anterior tendon (TAT), and lateral retinaculum (LR). These were harvested and tested to determine if their biomechanical properties compensated for the lack of the ALL. The TAT had the largest average Young's modulus, followed by the LCL, and then the LR. The LR had the longest average end of toe region, followed by the TAT, and then the LCL. The properties of these anterolateral structures, the lifestyle, and the evolutionary path of S. scrofa likely offer insight as to why this species might lack an ALL. This study concludes that S. scrofa does not serve as an animal study model for the anterolateral ligament.