[Chernabog]

Hi everyone,
I am new here, so sorry if I am posting in the wrong section.
I recently got a 18-inch spiderman 2 figure, pretty happy with it since it has like 70 articulation points.
However, being used its legs are so incredibly loose that it barely stands.
Basically, they drop for gravity whatever the position is. I am not sure what the joint type is, well basically I don't know how to call it, it's a mix of ballpoint and hinge perhaps? That hinge one with "steps", like with 5-7 standard angles of rotation.
Any idea how to fix it? It seems to be deep in the waist and I can't take it apart as it's welded

Thanks in advance!

p.s. I tried the polish thing already where the legs physically rotate and atach, without any luck