How you can use what details you have left to recreate and restore the photo
This wasn’t going to be a simple fix by any means, but with a bit of thought and some patience we can fix this.
First we can make a rough selection around the left arm and copy and flip it and then puppet warp it to make it straighter. Notice how she is leaning on this arm. It is likely that it was locked out to support her.
Next we can use the same copy and flip with some transform to add back the outline of the leg.
We can then copy some skin texture from the other leg down onto the lower leg.
The foot will take some hard work though. From the original shoe we can copy up the bottom two crossed laces to make more parts the central area and repeat all the way to the top. Shading some ankle shadows to complete shoe. We can then duplicate the shoe and rotate it over the one that needs fixing. With some puppet warp the shoe can be bent to look like it is on the correct foot.
Then all we need to do is add some harsh shadows to mimic the flash light.
All sounds simple but each stage was carefully blended and shaded to fit into the scene. Each layer had it’s own layer mask so each replacement part could be cut out and moved if needed.
If you need further explanation just ask. It took around 2.5 hours. You can watch a course on how to replace missing pieces here