Maybe you can be more specific. My impression of the OP is that some of the supporting ribs are broken. I'm not a pool professional but here is my take:
They do not have any function related to keeping DE out of the pool, the cloth that covers them does. If the cloth is ripped then DE will escape. The ribs are designed to keep an optimum shape to the grid and enhance the filtering. If too many ribs are broken the filter may perform so poorly that the grids need replacement. In addition the misshapen grids may cause enough turbulence in the filter that it may cause a rib to puncture the cloth and then of course let DE into the pool.