Let’s take a look at Iliotibial band syndrome (ITBS). AKA ITB friction syndrome.
People who participate in intense physical training, such as runners, cyclists, and military recruits, are most susceptible to ITBS. They may notice a sharp pain that comes and goes at the outside of the knee. Over time, the pain may become more pronounced.
The iliotibial band is a wide strip of fibrous tissue that extends down the outside of the upper leg. It begins at the top of the pelvis, at a bony prominence called the iliac crest, and travels down the outside of the thigh, continuing over the outside of the knee joint. The bottom of the IT band attaches to the top of the tibia (shinbone). One of its functions is to help stabilize the knee joint.
The IT band may rub uncomfortably against the bony bump on the outside of the femur at the knee. It may also compresses other soft tissue near the knee joint, such as a bursa or fat deposits near the knee, causing painful irritation. Either of these actions may result in the IT band itself becomes inflamed or otherwise injured.
Pain is usually felt at the outside of the knee; but can also come up the thigh, or into the side of the pelvis. When mild ITBS may only feel knee pain at the middle or end of a workout, but as the condition progresses, you may feel pain while simply walking or going down a set of stairs.