Most savs are wild caught and the importation process is difficult to survive intact. Odds are that the kink is a result of a broken bone in the tail during the slow boat ride from Africa.
If the kink is not a result of physical damage from shipping then it could be the result of physical damage from being kept with other savs. Groups of predators + tail tips that resemble food + jaws with bone crushing force can often = broken or missing limbs.
In either case you should be okay as long as the area doesn't get swollen but it may be a good idea to go to a vet for some tests for internal infections. Infection should be rare but remember that these guys were kept in awful conditions and deprived of 130 degree+ basking spots for an extended period of time so something could have set in while their immune system was weakened.
If it isn't physical damage then you may be dealing with the results of improper husbandry. The best way to combat that would be to read the following site and apply what you learn:
http://savannahmonitor.co/