The Athletic Advisor Patellar tendinitis or jumper's knee is a condition resulting from overuse of the knee. The patellar tendon is a structure that attaches the quadriceps muscle group to the tibia (shin bone). The patella (knee cap) is a sesamoid (floating bone) incorporated into the patellar tendon. The patellar tendon is also referred to as the patellar ligament; some anatomists believe ...