It depends whether or not the card agreement contained what's legally called a "joint" or "joint and several liability" condition.
http://en.wikipedia.org/wiki/Joint_and_several_liability
If it has one of theses conditions, you would become responsible for the debt if the other party named on it was given an absolute discharge in bankruptcy. If it doesn't have such a term, you are not responsible for any debts incurred on the card.
Assuming, the card does contain such a condition - and you need to check - if the card was defaulted on or no payments or SIGNED written acknowledgments were provided since the original default, the limitation period for filing court action in Ontario is 2 years if it was defaulted on AFTER Jan.1, 2004. If the card was defaulted on BEFORE Jan.1, 2004, then a 6 year limitation period for court action applies.
Even if the second case holds, the debt is likely coming up for being statute barred from legal action soon if it's not already so. Collection agencies always like to make last gasp bluffs about such debts as they approach their statue of limitation date. If anyone was going to sue you, they certainly would have done so a long time ago.
Ray