You do not always need to replace the entire window frame. A glazier can often remove the "sash" (the part of the window that holds the glass) and replace just the insulated glass unit (IGU).
When the (the one facing your interior) cracks, it presents specific challenges. Here is a breakdown of why this happens, what it means for your home, and what you can do about it. double pane window cracked on inside
A cracked inside pane is more urgent than a cracked outside pane for two reasons: You do not always need to replace the entire window frame
Double-pane windows are sealed units. The space between the two panes is filled with an insulating gas (like Argon or Krypton) and sealed at the factory to keep moisture out. Once one pane is cracked, the airtight seal is broken. The insulating gas escapes, and moisture-laden air enters. Here is a breakdown of why this happens,