Select the vertexes in red and for User dépacez the worms before on the axis Y.
Extrude and apply a small Bevel on the faces in red.
The object finished with Meshsmooth and some Crease.
The copy in position on the knee.
I added a part along the same lines of the design - a side protection to the knee.
From a Cylinder primitive with 8 dimetions, made a rotation of 22.5° on axis X
Make 2 Extrude/Bevel for the to form this mesh above
A series of Extrude/Bevel like above.
With one negative extrude made the hollow at the point.
Adjust the vertexes as shown
Extrude the 2 faces of the lower part, adjust the vertexes as shown and make a non-uniform scale to narrow the base.
Finally with the back of the object, Extrude to form hollow then Bevel.
As for the preceding object, made an instance copy to place on the leg as on the images.