Newcastle booked a grand-final place with a 22-14 win over Penrith, recovering from a 14-6 halftime deficit.
Sandon Smith's late try from an interception sealed the result as the Panthers struggled without Nathan Cleary.
Ivan Cleary confirmed his son needs surgery on both feet after suffering a compound fracture and dislocation of his left ankle.
The halfback had already been playing with a broken right foot, which Penrith had described as a "stress-related bone issue."
"He'll have to get the other foot done as well, because that was broken as well," Ivan Cleary said.
Cleary began the match on the bench for 25 minutes, then left the field after a hip-drop tackle by Newcastle hooker Phoenix Crossland, who was sent off.
"That's why I was even more emotional with what happened to him because I knew what he went through to get himself right to play today." Ivan Cleary said.
Penrith also lost Dylan Edwards to a ruptured PCL, Blaize Talagi to an Achilles rupture and Isaah Yeo, who needs surgery on a ruptured pectoral muscle.
Yeo's injury puts the Kangaroos captain in doubt for the end-of-season World Cup, while Cleary's injuries could also affect Australia's campaign.
The Panthers made seven second-half errors, and their hopes of a fifth premiership in their dynasty ended with the defeat.