Anesthesia for Hip or Knee Replacement Surgery

Anesthesia for hip or knee replacement surgery is a hot topic for several reasons. For one, patients are usually recommended either general or regional anesthesia. It’s up to you to gather as much information as possible to really understand your preference. Secondly, the thought of anesthesia can be nerve-wracking. Everyone has heard horror stories about anesthesia (whether fictional or not) that can make the idea of “going under” scary.

In reality, anesthesia is very safe but there is a lot of information patients should sift through and be aware of. Read on as we keep this post short and sweet and touch on what goes into choosing the right anesthetic for your joint replacement surgery; break down the differences in anesthesia types; and talk the pros and cons of each method.

3 Types of Anesthesia

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So what type of anesthesia is used for a hip or knee replacement? Well, there are 3 different types of anesthesia: local, regional and general. Local and regional are often confused with one another, but actually mean something quite different. Here are the differences:

  • Local—Numbs only the specific area treated. Think of local anesthetic as a numbing cream or injection. This type of anesthetic would not be used as a standalone method in a joint replacement. It may be used to numb the area where a spinal block or epidural block is administered. You are fully conscious with this method.
  • Regional—Blocks the nerves in a specific area to block out all pain or feeling. It does not affect the brain or breathing. With this method you are conscious (however, given sedatives to fall into a deep sleep). Think of this method as the “middle-ground” between local and general.
  • General—Medication is administered and you are completely and temporarily unconscious. A breathing tube must be administered to assist with breathing while you are “under”.

Don’t worry we’ll talk them out in greater detail with pros and cons before this article is over.

What Determines Your Anesthesia Type?

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  1. Your History: Have you ever had general anesthesia? If so, did you react well? Do bad reactions to general anesthesia run in your family? If you have had any bad reactions to general anesthesia in the past, it may not be the preferred choice for you.
  2. Your Health: General anesthesia (although very safe) is more risky than regional anesthetic. For this reason, if you are entering a surgery with additional risk factors (like being a smoker, being overweight, having a history of drug or alcohol abuse, having a comorbidity or secondary disease, having a history alcoholism, having drug allergies etc.) than you may not be a candidate. A clean bill of health is recommended for general anesthesia (especially for an elective surgery).
  3. Your Care Team: Just like your orthopedic surgeon has preferred implant brand manufacturers he/she works with and preferred approaches for hip replacement surgery, he/she will have a preferred method of anesthesia. This may differ based on each patient’s profile, but your surgeon will guide you toward the anesthesia method that they want for you.
  4. Your Preference: If you feel very strongly toward general vs. regional, your care team will certainly take this into account. If you’re scared of needles, you may prefer general anesthetic. If you’re scared of the idea of being put under, then you may prefer regional.

Another contributing factor is whether or not you're having inpatient or outpatient joint surgery. Regional anesthesia has a faster "bounce back" so is often preferred in outpatient joint replacement surgery. Continue reading to learn more!

Patient Risk-Factors for Anesthesia

These are patient risk factors for all the methods of anesthesia. However, these risks are heightened with general anesthesia. As such, to determine the best anesthesia method for your surgery, your care team will look at your risks factors. Here are the patient risks for anesthesia:

  • A history of seizures
  • A history of alcoholism or drug abuse
  • Bad reactions to anesthesia
  • Smoking
  • High or low blood pressure
  • Taking medications that increase bleeding (e.g. Aspirin. * Although, you will be told not to take these meds leading up to surgery).
  • Allergies to certain medications
  • Diabetes
  • Obesity

Two Types of Anesthetic for Joint Surgery: Regional vs. General

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Regional Anesthetic

Regional anesthetic can be thought of as somewhere between local anesthetic and full-fledge general anesthetic. With regional, the nerves are blocked to a specific area of the body. In joint surgery, this can mean blocking pain from the waist down (e.g. a spinal block) or could be as targeted as blocking pain on just one leg (e.g. a peripheral nerve block). It can also be quite temporary with a one-time injection, or a continuous flow of mediation can be run through a catheter lasting for hours.

Regional Anesthetic Cheatsheet:

  • Blocks nerves to a specific area of the body
  • You remain conscious
  • You are given sedatives to fall asleep
  • You do not have a breathing tube

3 Different Types of Regional Anesthetic

  1. Spinal Block: Anesthesia is injected into the fluid surrounding the spinal cord. This in in your lower back. The numbing effect last for several hours.
  2. Epidural Block: A catheter is put into your lower back to administer anesthetics. The epidural block and the spinal block are very similar. The difference is that an epidural is placed between the spinal column and spinal cord. A catheter is put in place for numbing.
  3. Peripheral Nerve Block: Anesthetic is injected directly around the major nerves in your thigh. This means that only the leg of the injection is numbed. A single injection lasts for only a short period. A catheter that slowly releases anesthetics offers a controlled numbing that can last as long as required. This method is not common in joint replacement surgery.

General Anesthetic

General anesthetic is reserved for major surgical operations. With general anesthesia, an anesthesiologist administers the medication through an IV or an inhalation mask that’s placed over your mouth and nose. General anesthesia will affect your entire body and brain—this means your breathing will be affected. A breathing tube will be put in and oxygen is given while you are “asleep” (technically, you are not just asleep but are in a medically induced coma). Throughout the surgery you will be unconscious, unresponsive, and will not remember the procedure.

Fun Fact: General anesthesia was first used during surgery in 1842.

General Anesthetic Cheatsheet:

  • Removes natural response to pain for the entire body (analgesia)
  • You are unconscious
  • You will have a breathing tube
  • It is very safe and low risk. However, certain patient risk-factors can make it a less desirable method for some.

Pros and Cons: Regional vs. General

What are the pros and cons of spinal vs. regional for a hip replacement? Or epidural vs. general for a knee replacement? Read on for the pluses and minuses for each anesthesia type. Which is safer, spinal or general anesthesia?

Regional Anesthesia Pros
Less blood loss.
Less nausea.
Less drowsiness. No “hangover”.
Better pain control.
Faster “bounceback” after surgery (get up on your feet faster).
Lower risk.
Patient-preferred.
General Anesthesia Pros
Completely unconscious (some patients are afraid of being “awake”).
No needle/ catheter in spinal region.
Tried and true method.
Regional Anesthesia Cons
Trouble urinating after surgery.
Headaches.
Allergic reactions.
Risk of nerve damage (very low).
General Anesthesia Cons
Breathing tube irritates throat (this is painful).
Less pain control (regional catheter can be left in to administer pain medication).
Nausea.
Drowsiness.
Slower bounceback.
Not for everyone (can be deemed “too risky” for some.
Riskier than regional (again, still very low risk).

Having a joint replacement? Preparing for surgery means a better outcome and speedier recovery. Sign-up for PeerWell and get matched with a surgeon who offers PeerWell for free.

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Hi, I'm Grace. I write all things surgery for the PeerWell blog. You may remember me from such titles as: "Diabetes & Joint Replacement 101" & "Sex After a Joint Replacement".

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