What does it take to be named as one of the fastest growing private companies in Los Angeles?

Here’s the heartening answer: There are probably as many ways as there are members of the Business Journal’s annual list of 100 firms.

Bing Howenstein, the founder of No. 1 company BackJoy Orthotics LLC, the maker of a $39.95 back orthotic, realized he was onto something after installing a prototype over his uncomfortable car seat – and getting some relief.

For David Schofield, the president of No. 3 Hometown Telecom, the eureka moment came when he and his partners realized cheap international calling card plans could sell even better if the service was offered over the Internet – and the plastic was ditched.

This annual survey ranks the 100 local companies by revenue growth from 2007 through 2009 and profiles the top five. All were feted last week at an event held at the Lexus Club in Staples Center.