Tendons connect muscles to bones. They are made of strong, flexible bands of tissue that help your bones and joints to move when your muscles contract.
Sports injuries that affect the tendons are common in football, skiing, lacrosse, hockey, rugby, running, squash, and tennis. Most tendon injuries affect areas near joints and, although they can appear to happen suddenly, in most cases they are caused by a number of tiny tears to the tendon over a long period of time.
Tendinopathy, where tendons around the knee become painful and swollen restricting movement, is usually caused by over-use or repeated minor accidents. Tendinopathy tends to be a long-term (chronic) condition and is unlikely to need surgery. It can often improve with a course of physiotherapy.