I've recently read some comments by Jonathan Bell, a prominent knee specialist in the UK and keen skier, on this. He says it is fine, even with a new knee, as long as you have rehab properly and have built up the muscles again so that the knee is fit. He knows several professional skiers with either partial or complete knee replacements who still ski to high levels. I believe he also has had a PKR and is still a keen off-piste (back country) skier and also does ski touring.
