Over the years I have repaired drywall damage more times than I care to remember. Most of the problem comes from my dogs racing around corners and crashing into themselves during "play" time. The dogs in question are a pair of Rottweilers. During my last round of repairs I figured out a way to reinforce the wall edge for better durability and it did not require much additional work or expense.
The first step in any repair is to make sure the foundation is solid. For my repair, this was the corner bead. The corner bead is the plastic or metal material they used to create the rounded edge or square edge as the case may be. After your remove all the broken paint and plaster you will find the corner bead underneath. Mine was only nailed to the studs every 16 or so inches. Since this was a high traffic area I added screws every 4 inches instead.
After securing the corner bead with screws proceed with the normal repair methods.
1. Clean the area of all loose material.
2. Apply a thin layer of Spackle.
3. I then add fiberglass tape and then apply another thin layer of Spackle. Let this dry for about a day.
4. Apply any additional layers of spackle and sand to bring the repair up to the correct level and let this dry again.
5. Apply and finish off with a suitable texture to match the wall area. Our house has a knock-down pattern which is nothing more than globs of plaster that have been been sanded flat.
6. Thoroughly clean the surface with a wet rag to remove any remaining dust and do a final inspection. At this point your ready to repaint the surface.
7. If you want to increase the durability of the wall you can apply fiberglass resin just before painting. The resin is easy to work with and is widely available at Home Depot, Lowe's and most auto supply stores. A quart can cost less than $15 and should last for at least a dozen corner repairs.
8. Before you add a resin layer to your hard work you should test for paint adhesion first. You don't want to find out after the resin is applied because it will be very difficult to remove. I used a Home Depot Behr latext paint and had no issues with the paint adhering to the resin but your results may differ depending the paint you use.
This technique should work for any wall that has a texture even though the resin is pretty thick when applied. If you have a smooth wall you should leave a slight indention to allow for the thick resin coating. You will likely have sand it more to match the existing wall surface too. Don't forget a face mask for protection if you end up sanding the resin for any reason other than "roughing" the surface prior to painting.
9. Mix the resin in a small batch according to the instructions on the can. It should be just big enough to do 1 coat. I applied 3 coats over the course of 2 days. You will need 1 brush per coat as the resin will destroy the brush and it cannot be cleaned. You want to paint the resin 1-3 inches on either side of the corner to create a hard shell of protection. In my case I was repairing a short pony wall so I had a top edge to cover also.
10. The final coat I let for a full day before lightly sanding it with 80 grit. Wipe the surface with a clean wet rag and apply a couple of coats of paint.
Oh, here is a tip...protect the wall from dog traffic while the resin is setting up. I had a dog cut the corner short leaving a thick layer of hair embedded in the resin requiring a little extra sanding. It did not do the dog's fur coat any favors either.