I've googled: why would a quadricep muscle be removed, injured quadricep, dead quadricep tissue, quadricep muscle removal, quadricep avulsion. Wikipedia only gave me the definition of quadriceps. Web MD gave me a number of knee conditions, ACL surgery, etc. In fact, most of my searches brought me to either tendon surgery or knee surgery.
Can anyone imagine a scenario where a muscle had to removed? I had thought of a large soft tissue sarcoma, but wasn't sure because then the spectre of cancer would be hovering over the character. It can't be a blood clot. Thanks!
ETA: Thanks so much, everybody! Been reading and looking at lots of gross pictures. Not sure what I'll got with...probably compartment syndrome with complications.