Runners knee affects what bone in your body?

Runner’s knee most commonly affects the patella, or kneecap. The condition is often called patellofemoral pain syndrome because it involves the joint relationship between the patella and the femur, the thigh bone. Pain is typically felt around or behind the kneecap, especially during running, squatting, stair climbing, or prolonged sitting with the knee bent.

The patella is a small, roughly triangular bone embedded in the quadriceps tendon. It protects the front of the knee and improves the leverage of the muscles that straighten the leg. During movement, it glides in a groove at the lower end of the femur. Repetitive stress, changes in training, muscle weakness, poor tracking, or an injury can disturb that motion and cause pain.

“Runner’s knee” is a broad everyday term rather than one single diagnosis. It can refer to several overuse problems, including patellofemoral pain syndrome, chondromalacia patellae, and sometimes iliotibial band syndrome. Even so, for a general-trivia question asking which bone is affected, patella is the standard canonical answer.