The family made the revelation in a post on the singer's Facebook page.
They said the Medical Examiner told them the final cause of death this morning was an accidental drug overdose.
"Unfortunately Tom's body suffered from many serious ailments including emphysema, knee problems and most significantly a fractured hip," they wrote.
But despite the injury his family said that Petty wanted to keep touring, not wanting to let down his fans.
"Despite this painful injury he insisted on keeping his commitment to his fans and he toured for 53 dates with a fractured hip and, as he did, it worsened to a more serious injury. On the day he died he was informed his hip had graduated to a full on break and it is our feeling that the pain was simply unbearable and was the cause for his over use of medication."
The family said they took solace in the fact that his death was likely painless. They also hoped that this revelation would prompt further discussion about the opioid epidemic.
"As a family we recognize this report may spark a further discussion on the opioid crisis and we feel that it is a healthy and necessary discussion and we hope in some way this report can save lives. Many people who overdose begin with a legitimate injury or simply do not understand the potency and deadly nature of these medications."
You can read the full statement on the singer's website