The anterior cruciate ligament (ACL) is one of the four major ligaments of the knee. This ropelike structure in the center of the knee helps maintain stability. The ligament has a bony attachment to the femur as well as the tibia. The tibial attachment is known as the tibial spine. In some injuries where the ACL appears to be torn, there is actually an avulsion fracture of the tibial spine, meaning that the ACL has pulled a fragment of bone away from the rest of the tibia. Patients often have similar symptoms to an ACL rupture, such as swelling, pain, and instability. It is important for the tibial spine fracture to heal properly and restore stability to the knee. Surgery is often required to reduce and repair the bone fragment and ACL back to the tibia.
