How to use a meta-analysis to assess the equivalence of two different procedures?

I'm making a comparison of two surgical procedures, and I want to know how I can analyze the data I have for a meta-analysis. The overall surgical procedure is the same, but some authors choose to modify the procedure a bit. So basically I have a large number of studies with the standard procedure and a smaller number with a modified procedure.

The outcome is percent complications, e.g., 20% of the study population had mild complications and 10% had severe complications.

What would be the best way to show if the modified procedure is as good as the standard procedure?