Does the human knee bone, the patella, connect to any other bone?

It is attached, but by tendons instead of ligaments.

"The patella claims for itself alone that it is not attached to another bone by ligaments but is connected by the tendons which bypass the knee joint 10 and is very powerfully bound to the femur."

http://vesalius.northwestern.edu/chapters/FA.1.32.html

Also, the patella is the largest sesamoid bone in the human body and is attached to the tibial tubercle on the front of the tibia.

"The patella, also known as the knee cap, is a thick, triangular bone which articulates with the femur and covers and protects the knee joint. It is the largest sesamoid bone in the human body."
https://en.wikipedia.org/wiki/Patella
https://en.wikipedia.org/wiki/Sesamoid_bone

"The patellar tendon attaches to the tibial tubercle on the front of the tibia (shin bone) just below the front of the knee. It also is attached to the bottom of the patella (kneecap). At the top of the patella, the quadriceps tendon is attached. At the tope of the quadriceps tendon is the quadriceps muscle."
http://www.bostonsportsmedicine.com/pdf/protocols/Quadriceps%20and%20Patellar%20tendon%20repair%20rehabilitation.pdf