Dislocated knee cap 3 weeks moved outside knee I straightend leg it went back in place, very swollen, weightbearing ok, stiff, ok walk without brace?

Patella. May have patellar avulsion fracture, loose body. Check with orthopedic surgeon if you need brace, pt, or surgery.
Would not recommend . First of all, have you seen someone about this? If not i would highly recommend it. If the brace you have is the type of brace that pushes the kneecap over toward the inside of the knee then i would recommend you continue using it until you have seen someone and had it evaluated.