Crocs, Inc. calls itself a world leader for innovative casual footwear for all. 

And selling 300 million pairs of shoes sold in the last 13 years makes the claim hard to argue.

But the Huffington Post reported this month that podiatrists are not as high on Crocs as others — if people are wearing the shoes all the time.

The Huffington Post quoted several experts who said Crocs should not be used for long walks in part because the shoes do not secure the heel properly.

"When the heel is unstable, toes tend to grip which can lead to tendinitis, worsening of toe deformities, nail problems, corns and calluses," Dr. Megan Leahy, a podiatrist with the Illinois Bone and Joint Institute, told the Huffington Post. "The same thing can happen with flip flops or any backless shoes as the heel is not secured.”