Your surgeon will be very careful during surgery to keep down the amount of blood you lose.
However, blood may continue to ooze from muscle and bone surfaces that were cut, even after the operation is over. Many patients need a blood transfusion after knee replacement surgery. A blood transfusion is a safe, common procedure, in which you receive blood through an intravenous (IV) line in one of your blood vessels.
If you need a blood transfusion, there are several sources of blood:
You may receive donor blood from the general public, after it has been closely matched to yours. Blood that has been matched should not cause a reaction when you receive it.
You may be able to receive blood from a relative or friend, if their blood matches yours. Your relatives and friends will have to donate their blood weeks before surgery, so it can be checked and stored for you. This is known as direct blood donation.
Ask your doctor about autologous blood donation. This is when you donate your own blood weeks before your surgery, and it is stored for you, in case you need a transfusion.
Blood from the Public (Volunteer Blood Donation)
The most common source of blood given during or after surgery is from volunteers in the general public.
If you choose this method of receiving donated blood, you will have no extra costs or further tests.
Many communities have a blood bank at which any healthy person can donate their blood. This blood will be tested to see if it matches yours.
You may have read about the danger of becoming infected with hepatitis, HIV, or other viruses after a blood transfusion. Blood transfusions can never be 100% safe. However, the current blood supply is thought to be safer now than it ever was before.
Any donor answers a detailed list of questions about their health and risk factors for infection before they are allowed to donate.
Donors answer very direct questions about risk factors for infections that can be passed on through their blood. This includes sexual practices or habits, drug use, and current and past travel history.
Blood centers keep a list of donors who may not be safe.
Donated blood is tested for many different infections.
Directed Donor Blood (Blood from a Family Member or Friend)
This method involves getting a family member or friend to donate blood before your surgery. This blood is then set aside and held only for you, if you need blood transfusion after surgery.
Only family members or friends whose blood matches yours can be used. You will need to donate a unit of your own blood first. Then blood from these potential donors will be tested to see if their blood matches yours.
Most of the time, you will need to make arrangements with your hospital or local blood bank before your surgery to have directed donor blood.
Blood donated from these people must be collected at least a few days before it is needed. Their blood is carefully screened for infection.
It is important to note that there is no evidence that receiving blood from family members or friends is any safer than receiving blood from the general public.
Autologous Blood Donation (Blood from Yourself)
Although the blood donated by the general public and used for most people is thought to be very safe, some people choose to use a method called autologous blood donation.
Autologous blood is blood donated by you, which you can later receive if you need a transfusion during or after surgery.
You can have blood taken from 6 weeks to 5 days before your surgery.
Your blood is stored and is good for a few weeks from the day it is collected.
If your blood is not used during or after surgery, it will be thrown away.
If you wish to donate your own blood, you must make arrangements yourself. Your hospital may be set up to receive these donations and store the blood. Otherwise, your local blood bank may handle this process. Most of the time, you will need to pay for this process yourself.
Problems can happen with autologous blood donation:
Donating this blood can make you anemic, or have lower blood count, before your surgery. In fact, it is still possible that you will need to receive a blood transfusion with blood donated by the general public.
Rarely, a mistake by the blood center or the hospital when handling your blood can end up with you receiving the wrong unit of blood, causing a reaction to the blood.
Your doctor may ask you to take extra vitamins and minerals to help your body make new blood cells. These include:
Folic acid, 1 mg once a day
Vitamin C, 250 mg twice a day
You may also get a shot to boost your blood count prior to surgery.
Boulton FE, James V. British Committee for Standards in Haematology, Transfusion Task Force, Guidelines for policies on alternatives to allogeneic blood transfusion. 1. Predeposit autologous blood donation and transfusion. Transfus Med. 2007 Oct;17(5):354-65.
C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery, and Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.