My husband got DeQuervain's tendonitis (of the thumb) when our daughter
was brand new - we determined that it was due to his positioning when
holding her while walking - he improved with thumb splinting (in a thumb
spica), ice, and a change in positioning.   I got it last year when she was
just 2 - also probably from the way I was carrying her, since she had
recently balked at her sling and other carrier.  I also got better with
splinting, ice and and change.  I got it again a few months ago, and an
occupational therapist recommended contrast baths (20 seconds in cold water
then 20 seconds in hot) and controlled stretching  - I got better a lot
faster the second time.

I have seen several women with tendonitis of various upper extremity
tendons from positioning during feeding or from carrying - adjusting
positioning, ice and gentle stretching works great.  Surgery for
DeQuervain's??? - sounds harsh.
Julie Graves Moy, MD, MPH
Austin, Texas