A healthy young athlete is sitting at the edge of the table with knee at 90 degree flexion. He fully extends it. What will happen?

In a normal knee flexed 90 degree, the tibial tuberosity aligns with the medial half of the patella. The tibial tuberosity moves laterally during extension and aligns with the lateral half of the patella at full extension. Ref: Basic Biomechanics of the Musculoskeletal System, 3e By Margareta Nordin, Victor Hirsch Frankel, 2001, Page 184.