Subluxation is another word for partial dislocation of a bone. Patellar subluxation is a partial dislocation of the kneecap (patella). It’s also known as patellar instability or kneecap instability.

Patellar tendonitis — also called jumper’s knee — is a type of knee tendon pain. It happens when the tendons connecting the kneecap to the shinbone become inflamed from overuse. Repetitive motions, ...