Knee Pains

A woman goes to the doctor complaining of bad knee pains. After the diagnostic tests showed nothing, the doctor questions her:

- There must be something you're doing that you haven't told me. Can you think of anything that might be doing this to your knees?

- Well - she said a little sheepishly.

- my husband and I have sex doggy-style on the floor every night.

- That's got to be it - said the doctor.

- There are plenty of other positions and ways to have sex, you know.

- Not if you're going to watch T.V. there ain't - she replied.