Context: About 8 years ago I injured my right knee in an accident . It took so long to heal , that I think I damaged my left knee from having it carry my weight . For the last 3 or 4 months , my knee was pain free . I injured my left knee about a month ago , and the pain is getting worse , to where it 's starting to affect mobility .

Question: Which medical specialty may I need to visit after posting this ?
Options:
0. None of the above choices .
1. Optometry
2. Orthopedics
3. Cardiology
Answer: 2