My parents have a friend who is a doctor, specializing in foot/ankle injuries and especially ligament tears in the ankle. Just in general, without referring to Spikes, I asked him about the Achilles tendon injuries. While it's not specifically his specialty, he said it can be a brutal injury, and happens more often to well-built, weight lifting types who build muscle mass but don't work to increase their flexibility. He said that unlike an ACL tear, where the ligament can be repaired and rehabbed so that it is even stronger than before the injury, the repaired Achilles will never be as strong as it was.
I think (hope) TKO will bounce back. I think we may see a difference in him, just because he was SOOOO explosive before, that it may be a little much to expect that type of athleticism. But I don't think he'll be reduced to a shell of his former self. I will take 90-95% of the old TKO any day.