I had a turkey to do this about the same age. We had to cull it. We tried splinting it but it seemed to stress her out even more. Your turkey will get to where it can't hardly move plus it will not put on weight because it can't get around good. Also my turkeys would always run over her. It will just get worse and plus the other leg will start to do the same thing.
Sorry for the bad news but just saying that I had the same experience.