Does patella tendonitis go away if you strengthen your quad muscles? Or is it there for life? Son 18 is go in military needs to know what to expect?

Gets better. With the proper treatment, tendonitis gets better. If he is doing something in particular, playing catcher baseball etc, he should rest from anything that is hurting for a month or so. Sometimes a plica can cause patella tendonitis problems or a small bone (ossicle) at the tuberosity. Sometimes surgery is necessary. 18 year olds should not have chronic knee pain.