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What you need to know about anesthesia for knee replacement surgery

Anesthesia is a medicine that blocks the feelings of pain and sensation during surgery. You will receive other pain medicine to give you pain relief during and after surgery.

Before surgery you will meet an anesthesiologist (doctor) and a registered nurse anesthetist who will review your medical history and talk with you about your anesthesia options. Your choice depends on your surgery, your medical and surgical history, and your physical condition.

The two types of anesthesia used for knee replacement surgery are general and regional anesthesia. (In addition to either general or regional anesthesia, you may need a femoral nerve block.)




Side effects

General anesthesiaGeneral anesthesia puts you to sleep during surgery. It acts mainly on your brain and nervous system and affects your entire body. You receive it by injection (shot) or by inhaling it. A breathing tube helps you breathe while you are under the anesthesia.General anesthesia may be more appropriate for longer or more involved surgery. It may also be used if the position you’ll be in during surgery is uncomfortable.Minor side effects such as sore throat, headache, hoarseness, nausea and drowsiness are the most common. These side effects usually go away in one day.
Regional anesthesia
(including spinal anesthesia)
Regional anesthesia blocks sensation to a limited area of your body. It is usually given with light sedation, which allows you light sleep while your surgery area is numbed. You receive it by injection (shot). Spinal anesthesia numbs the lower half of your body for about 3 to 4 hours. You receive an injection between the vertebrae. Epidural anesthesia allows you to receive pain medicine after surgery. A thin plastic tube (catheter) is placed in your spine to allow for extra injections or medicines after surgery.Less medicine is needed so you wake up more quickly with less chance of nausea. Regional anesthesia can be less stressful to your heart and lungs than general anesthesia can be.Minor side effects such as small headaches or trouble urinating are the most common. These side effects usually go away a few days after surgery.
Femoral nerve blockRegional nerve block is used to limit sensation to the front of the thigh, femur (thigh bone) and knee joint. You will receive an injection (shot) into the thigh to make this numbness occur. A regional nerve block lasts an average of 16 hours.While the block is working, you will have less pain than you would normally have after total knee surgery.You will have difficulty supporting your weight on the affected leg until the regional nerve block has worn off.

After surgery you are taken to the recovery room or PACU (Post Anesthesia Care Unit). Most patients stay 1 to 2 hours. You may stay longer, depending on your surgery and how fast you recover from your anesthetic. The anesthesiologist and the recovery room nurse will care for you as you wake up from the surgery.

Depending on the anesthesia used, you may wake up with an oxygen mask on. You may also have blurred vision, a dry mouth and chills. Your nurse will monitor all your vital signs and help you if you experience any side effects from the anesthesia.

You may have some discomfort and pain when you awaken. Everyone has a different pain threshold and reacts to pain differently. Your nurse will work with you to make you as comfortable as possible.

You will be taken to the patient care area when your medical status is stable.

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Source: Allina Patient Education, Total Knee Replacement, third edition, ortho-ahc-90140

First published: 10/01/2000
Last updated: 12/01/2006

Reviewed by: Allina Patient Education experts