Hiya bob, well not any more they don't! I had a total knee replacement operation on my left knee just two weeks ago, so I now have one very painful bionic knee with a fairly long, fairly tidy scar & an infection & bandage and those dreadful un-sexy anti- thromosis knee sox ... and one rather dodgy natural knee, contemplating desertion or suicide at the thought of having to go through the same as the first one!!!! The new one is not enjoying learning to walk and the old one is on strike LOL. I just can't win at the moment! So glad to have my lovely RATTER looking after me so well. Don't konw what I would do without him!... Am threatening to match the two up in about three - four months time. So, until then .... the answer to your question is most certainly no!