IPP is Imprisonment for Public Protection, where the court judges that there is "significant risk to members of the public of serious harm" from further offences.
Broken bones usually amounts to GBH,not the lesser ABH. GBH with intent can mean life imprisonment. GBH without intent has a maximum 5 year prison sentence.
The IPP will set a minimum period that he must be imprisoned - so the sentence could be, for example - 10 years prison with a 7 year tariff - which means he must serve at least 7 years. And on release he will be on a supervision license for a number of years.
It is difficult to predict his sentence.