58yo female/163cm losing muscle continuously down to the bone

Started from a minor bone fracture by a misstep on the stairs while walking outside. Started physio 4 months after injury, but have been continuously losing muscle since physio. did an EMG for both legs 2 weeks ago, and now muscles have been losing at an even faster rate.

Couldn’t find what was wrong from the EMG. Doctors can’t find anything wrong with my mom.

Feels soreness/pain after exercise

Could her spine injury from lifting heavy things at her job from years ago have caused this? Maybe the spine injury was exacerbated after her foot fracture since have to use her hips more to move instead of legs?

Please help me diagnose what could be the issue if you might know? my mom and I are terrified. She’s gonna to end up in a wheelchair at this rate