The fibula is a small bone that runs parallel to the tibia down to the ankle. This cartilage helps the knee move smoothly.
Ligaments connect bones and help keep the knee stable.
The anterior cruciate ligament, posterior cruciate ligament, and medial collateral ligament all connect the femur and tibia together. The lateral collateral ligament connects the femur and fibula. Each ligament has specific functions in the knee. For instance, the anterior cruciate ligament helps prevent the tibia from coming too far forward. Patients who tear this ligament often have unstable knees that can collapse, causing falls.