ARTHRITIS OF THE KNEE JOINT

We do everything we can to minimize blood loss during surgery. Your blood pressure is lowered during the operation to cut down on bleeding, and cut blood vessels are zealously cauterized, and we use the smallest incision possible. Even so, almost all knee replacement patients need to be transfused after the operation because of oozing from cut surfaces, much of it occurring after the operation is over.

First time knee replacements require a 1 to 2 unit transfusion of blood. Revision knee replacements needs 2 to 3 units or more.

The advent of AIDS has highlighted the risks associated with using other people’s blood (see Diseases Transmitted Through Blood Transfusion, below). Dr. Huddleston has always recommended that his patients donate their own blood prior to hip surgery because of the other risks associated with transfusion. The blood is stored and given back to you at the time of the operation (see Autologous Donation below). If you are not able to donate blood for yourself (for whatever reason), it is recommended that you solicit family members or friends to donate on your behalf (see Directed Blood below). Sometimes a combination of these two methods is chosen: that is, you may donate one unit of your own blood and request friends or relatives to donate two units. Your third option is to use “hospital blood” (see Volunteer Donor Blood below).

1. Autologous Blood is blood donated by you and later given back to you. It is stored in a liquid state and is good for 42 days from the day of collection. It can be stored frozen for up to a year, but freezing triples the cost and is therefore only used in very special circumstances.

Usually two units of blood are taken from at approximately one-week intervals in the weeks before your surgery.

More can be taken over a longer period, but some of the units may have to be frozen if storage is required for more than 42 days. Note that blood already being stored in liquid form cannot be frozen if your surgery is postponed for any reason. Freezing must be done at the time of collection. If you have already given your blood for storage, and your surgery is to be delayed for any reason, we can use the “piggy-back” technique to save a unit of your banked blood that is about to expire. We give it back to you as a transfusion, wait ten minutes, and then take a fresh unit that will be good for another 42 days!

There is no age requirement for storing your own blood, and no specific weight requirement. However, if you are anemic (Hemoglobin under 11 gm/dl), we cannot take your blood. There are also some medical conditions which might preclude you from donating your own blood, such as some heart disorders.

It is advisable to take minerals and vitamins to help your body replace the blood lost by your donations. Take these from the day of your first donation until the day prior to surgery: 1. Iron (Nu-Iron 150), 1 tablet 2 times a day. 2. Folic acid, 1 mg once a day. 3. Vitamin C, 250 mg twice a day.

2. Directed donor blood is blood donated by a relative or friend. It is carefully labeled and reserved specifically for you. It is rigorously tested for disease, but it is still possible to contract disease through directed blood: the donor may not know he has the disease, and tests may fail to detect it. Directed donor blood is only given to you after surgery if it is medically necessary to do so. If you plan to have directed donors, it is best that you first donate a unit (450 cc) of your blood. Then, when your blood group is known, and the bank has a specimen of your blood to use in cross-match tests, suitable donors can be canvassed. Bear in mind that it takes a minimum of 48 hours to process and test blood before it can be transfused.