What does tibial tuberosity bilaterally signify?

That you are normal. The tibial tuberosity is the bump of bone on the upper part of your shin to which the tendon from the kneecap attaches. If you are asking a question about an x-ray interpretation, i think you may have left something out of your description.
Insertion quadreceps. Tibial tuberosityis the insertion of the patellar tendon, or the insertion of the quadriceps mechanism - one of the largest muscles in our body. In a growing child tenderness over the tubercle could be a sign of osgood-schlatter's syndrome. In adult a large tuberosity could be the result of osgood-schlater's syndrome as a teenager. Pain in adults could be from a bursitis behind the tendon.
Part of leg bone. The term "tibial tuberosity" is an anatomical term that refers to the bump of bone just below the knee cap. It can be the site of pain because this is where the quadriceps tendon attaches. This tendon pulls on the bone from the contraction of the thigh muscles and straightens your leg in the direction of a forward kicking motion.