Q. What is runner’s knee?
A. “Runner’s knee” refers to several possible conditions that cause patellofemoral pain, or aching around the front of the kneecap. “It’s a grab bag,” says John Richmond, chair of orthopedic surgery at New England Baptist Hospital. The pain often results from an overuse injury, which develops over time when you over-stress a particular part of the joint, rather than because of a single traumatic injury. Running is the most common cause, he says, because it’s popular and generates high forces on the knee, but other kinds of exercise and sports can irritate and inflame the knee.