I was a dog trainer for 20 years & have lots of experience with e-collars. They can be effective when used properly for a variety of issues such as excessive barking. However for your situation I wouldn't recommend it. I agree w/ Mickeyfan... tie outs are dangerous, can & likely will cause you a bunch of other unwanted behavior issues. If your yard is fenced but clearly not secure it is worth the pennies to fix that. If that fix is really too costly then the largest, most secure dog run you can afford. If you go dog run make sure it is big enough for two & add extra toys & things like Nylabones if they won't fight over possessions, in addition to plenty of exercise.
The underground wiring that goes with the ecollar for the yard can be costly. Plus I have personally watched MANY dogs take the shocks for freedom(O: Once the shocks are over & they have crossed the line its party time. Particularly since your dogs have already experienced the reward of breaking out. You also have two, pack mentality is a very powerful thing.
How are they getting out?