The tendon can't glide smoothly through it, and over time it may become inflamed as well. An inflamed tendon develops a nodule which, when it moves through the A1 pulley, creates a painful popping or ...
Repeated physical stress and movement leads to inflammation in the specific point where your shinbone (tibia) meets the tendon from your kneecap (patella). It causes a painful lump below the kneecap.