The former New Zealand Warriors rugby league captain, television personality and noted pugilist pulled out of a defence of his national cruiser weight belt in Taranaki in June after a MRI scan revealed some issues.
Betham, 38, was scheduled for a rematch with James Langton whom he defeated in an unanimous points decision when the pair met in Auckland late last year.
Betham finishes his career with an 8-1 record in the cruiser weight division after taking up boxing after retiring from rugby league.
It was anticipated that his rematch with Langton, who has a 10-4 record, was also to be for the IBO Asia Pacific belt and would have helped him towards a possible tilt at the IBO world title.