Dear Dr. Gott: Last October, I had my second knee replacement. I really don't think it was done correctly.

Before I had the surgery, my left kneecap would slide to the left and lock. The doctor told me it should be replaced. Now, after the surgery, it continues to do the same thing. I often have to take my hand and push it back into place. It happens a lot when I go up and down stairs. Does this sound right to you?

Reply: I am not an orthopaedic knee surgeon. You were told you needed a knee replacement because of a problem with your kneecap, yet, after the surgery, you have the same problem. This suggests that something was not done correctly.

I recommend you return to the surgeon who operated on you and ask why you had the knee replaced if it did not fix the problem. You are entitled to answers. If your surgeon refuses to help, ask for a copy of your medical and surgical records so you can take them to be reviewed by a second orthopaedist, who may be able to tell you what is happening and whether it was a problem with the surgery or something else.

To give you related information, I am sending you a copy of my Health Report "An Informed Approach to Surgery". Other readers who would like a copy should send a self-addressed, stamped envelope number 10 and $2 to Newsletter, PO Box 167, Wickliffe, Ohio 44092. Be sure to mention the title.

Dear Dr. Gott: My four-year-old grandson recently had tubes put in his ears because of several earaches. I remember as a child using eardrops, heating pads and bags of heated rock salt. Will these tubes dissolve or need to be removed as he grows older? Will they affect his balance and equilibrium during everyday activities and sports? I am completely clueless about this. Please help.

Reply: Tubes placed in the ear are surgically implanted through the eardrum to allow fluid to escape easily rather than build up and cause infection. They will not dissolve and in most cases fall out after about a year. The tubes are minute, and, chances are, he will never know when they have fallen out.

As far as affecting his balance, yes, they will affect it, but in a positive way. An ear infection is basically a build up of fluid within the ear, often behind the eardrum. This can push on the sensitive ear parts, causing pain, swelling and a loss of balance. With the tubes in place, this fluid can drain away freely, which means no infection, swelling or balance problems.

I remember the drops and heated water bottles, too. Thankfully, today, our children and grandchildren do not have to suffer as we did. Repeated middle-ear infections can cause permanent damage and hearing loss. Drops and heating pads merely made the infections more bearable. Tubes, however, are helping these unfortunate repeat sufferers to avoid these risks.

Dr. Gott is a retired physician and the author of the book "Dr. Gott's No Flour, No Sugar Diet" and "Dr. Gott's No Flour, No Sugar Cookbook" .Contact him c/o United Media, 200 Madison Avenue, fourth floor, New York, New York 10016. However, if readers want to request a newsletter, they should write to the Ohio address.