bone Transform misplaced in Unity

Hello everyone, on 3.5.7, I have a problem that is ruining my animations : the bones transform of my character's fingers aren't at the right place. The model is rigged using a biped with 3DS Max. as you can see on the image below, I select the base of the character's index, and the transform isn't at the right place. The gap is only on the Z axis, and occurs on every fingers of t$$anonymous$$s particular character.

When reimporting the model on 3DS Max however, the bone is at the right place...

On t$$anonymous$$s gif, you can see the finger :

• with its original rotation

• rotated 90° counter clockwise

• rotated 90° clockwise