Most total knee replacements are performed under general anaesthetic, which means you will be asleep throughout. But patients may also be offered spinal anaesthesia – or epidural – which numbs you from the waist down but means you remain conscious throughout the surgery.
Controversy surrounds the use of spinal rather than general anaesthetic in total knee replacement surgery and many surgeons and patients prefer to stick with the tried and tested route. However, recent research suggests that spinal anaesthesia may result in better outcomes for patients.
The aim of this article is to present some of the primary findings and to encourage patients scheduled for surgery to talk to their surgeon about options for anaesthesia.
Research by The Mayo Clinic
An article published in Bone Joint Journal 2022 (104-B(11):1209-1214) outlined the findings of research from the Mayo Clinic in Rochester, Minnesota. Researchers wanted to look at pain control, length of stay in hospital and the development of complications in patients who had had a spinal anaesthetic for total knee replacement surgery, compared to general anaesthesia.
Methodology
The research team focussed on a single, high-volume academic centre. They identified 17,690 primary total knee replacements carried out on 13,297 patients between 2001 and 2016. Just over half (52%) had received general anaesthetic but 48% had had spinal anaesthesia. The patient profiles were similar between the two cohorts. There was an average of 68 and more than half of the patients (58%) were female. The average BMI (body mass index) was 32 kg/ m 2 (SD 7).
The researchers evaluated pain levels using oral morphine equivalents (OMEs) and the numerical pain rating scale (NPRS). They also looked at complications following surgery, including readmissions to hospital after 30 and 90 days. They analysed the data using an inverse probability of treatment weighted model.
Findings
The study demonstrated that patients who’d received spinal anaesthesia needed fewer oral morphine equivalents after surgery and had lower NPRS scores. There were also fewer cases of altered mental statues among this cohort and a lower chance of 30-day and 90-day readmissions to hospital. Patients who had a general anaesthetic were more likely to require any kind of revision surgery to correct problems with the primary total knee replacement and were also more likely to have any sort of reoperation. Based on their findings, the research team concluded that whenever it is possible and safe to do so, spinal anaesthesia should be considered in primary total knee replacement surgery.
Making an informed choice
Prior to any joint replacement surgery, your orthopaedic surgeon will discuss the full range of options available to you during your consultation, including anaesthesia. Professor Joseph Queally offers both general and spinal anaesthesia and will help patients to understand the pros and cons of each and make an informed choice about what is best for them.
Frequently asked questions
If you are due to undergo a total knee replacement, we recommend talking to your surgeon about the procedure and asking them to clarify anything you are unsure about. It can be helpful to prepare a list of questions in advance so you remember to ask everything that is on your mind. Some of the questions we get asked most frequently are:
- What is the difference between a partial and total knee replacement?
- What will happen on the day of my surgery?
- Are there any risks associated with this kind of surgery?
- How soon will I be able to go home?
- Am I suitable for Mako robotic arm assisted knee replacement surgery?
- Will I need to use crutches or a walker to get around?
- Will I be able to get up and downstairs?
- When will I be able to go back to work or drive again?
- What activities will I be able to do after I’ve had the knee replacement?
- Is there anything I need to avoid doing?
- What do you mean by a revision knee replacement?
- Can I see reviews or comments from patients who’ve had this procedure with you?
Many patients are understandably apprehensive about undergoing joint replacement surgery but feeling well-informed and have a clear understanding of what to expect in advance can help to alleviate many of these fears. If you are interested in talking to us about having a total knee replacement or have any questions about the procedure, please contact us.
