It's just an educated guess on my part, but it does come from a lot of experience and research. Having movement in the extremities means nothing was severed and almost always leads to a full recovery.

I've had 3 incidents in my life nearly identical to what Kemba did tonight. 2 on a football field and the other in my home slipping on my kid's toy and falling into a solid door. The pain is instant and intense, and there is a momentary loss of function, but that's from the initial impact shock and goes away fairly quickly. Each time I was good to go within hours(although that was without having to pass concussion protocols that likely would have had me resting for a week or 2).

I would be extremely surprised if he doesnt make a full recovery within 2-4 weeks.