Meilleure réponse !
You are the patient (tu es le patient) :

- Hi doctor!
- Hi.
- I have a problem. I forced my knee during my swimming lessons and now I can't move my knee anymore. Could you check my knee, please?
- Of course! ... Do you feel pain when I touch you here?
- No.
- And here?
- No.
- OK, then it's nothing serious, you'll feel better in 2-3 days.
- Thank you very much, doctor! 
- You're welcome.

You are the doctor (tu es le médecin) :

- Hi.
- Hi, doctor.
- I heard that you can't move your knee anymore, right?
- Yes, I can't.
- Could you tell me why do you think that you can't move it anymore?
- I don't know, maybe because I forced it a little bit during my swimming lessons.
- Oh yes, that's possible! It isn't good to force your knee. You should stop when you feel a little bit pain. I'll touch your knee and you'll say if you feel pain, OK?
- OK.
- Do you feel something when I touch you here?
- No.
- And here?
- No.
- Then, it's nothing serious. But I advice you to rest your knee during 2-3 days. 
- Thank you very much for your help, doctor!
- You're welcome.