No, they are not very common. Most literature focuses on more mainstream themes. However, in some niche areas of fantasy and adventure writing, you might come across such stories.
The transformation aspect. For example, like in the story where a character with a leg cast suddenly discovers it has magical powers that transform their situation. It adds an element of surprise.
Fantasy bondage stories involving leg casts can be quite unique. One could be about a character who has a leg cast and is in a situation where they are 'bound' to a certain place due to their injury, like an old castle. They start to have strange visions and adventures while being restricted by the cast.
One leg cast fantasy story could be about a young adventurer who breaks his leg while exploring a mysterious ancient ruin. Trapped there with a leg in a cast, he discovers a hidden magic that heals him and also gives him the power to understand the long - forgotten language on the ruin's walls, leading to a great discovery.
One long leg cast story could be about a kid who got a long leg cast after a skateboarding accident. He had all his friends sign it with funny drawings and messages. It became like a memory book of that time in his life.
There was a person in my neighborhood who got a full leg cast after a car accident. She was really down at first because she couldn't do her normal activities like going for walks with her dog or dancing. However, she decided to make the best of it. She started an online blog about her experiences with the leg cast, sharing tips on how to deal with the inconvenience, and she got a lot of followers. It was really inspiring to see how she turned a difficult situation into something positive.
One leg cast fiction story could be about a young athlete who breaks his leg right before a big competition. While in a leg cast, he discovers a hidden talent for painting and it changes his perspective on life. He then has to decide between continuing his sports career or pursuing art.
A full leg cast story could be about someone who got injured, like breaking their leg in a sports accident. They then had to get a full leg cast. It might talk about how difficult it was for them to move around at first, having to use crutches and relying on others for help.
One common theme is recovery. The long leg cast represents a period of physical healing, and the story often follows the character's journey from injury to getting better. Another theme could be limitation. The cast restricts the character's movement, so they have to find new ways to do things or rely on others.
A leg cast fiction could involve a detective who gets his leg broken while chasing a criminal. With the leg cast on, he has to rely more on his mental skills and the help of his partner. He starts to notice small details that he previously overlooked. Eventually, he solves a big case that was thought to be unsolvable, all while hobbling around with his leg cast.