Anaesthesia for Hip Replacement: What I Chose and Why

Most hip replacements are done under a spinal anaesthetic, which numbs you from about the waist down, usually with some sedation so you doze rather than lie there listening, and that turned out to be the part of the day I had worried about for the wrong reasons. I had pictured the anaesthetic as the frightening bit: a mask, a countdown, the fear of not waking up. What actually happened was quieter and stranger than that, and the choice between being put fully under and being numbed while awake mattered more than I realised. Here is what each option is, how the decision got made, and the things I should have asked before the morning of surgery.

The two main options

For a hip replacement the real choice is usually between a spinal anaesthetic and a general anaesthetic, and a spinal is the more common starting point. A spinal involves a fine needle placed into the lower back to deliver anaesthetic around the nerves in the spinal fluid, numbing the lower body for a few hours while you stay conscious or lightly sedated ¹. A general anaesthetic puts you fully unconscious, with your breathing usually supported through a tube or airway device.

The two are not mutually exclusive in the way the names suggest: a spinal is very often combined with sedation, so the practical experience sits on a spectrum from fully awake and chatting to deeply asleep. My anaesthetist described it as numb first, then as much or as little sleep on top as I wanted.

Why spinal is so often the default

The preference for spinal anaesthesia in joint replacement is not just tradition. A Cochrane review comparing techniques for hip and knee replacement found that regional anaesthesia such as a spinal is associated with less blood loss and a lower risk of certain complications compared with general anaesthesia ².

In hip surgery specifically, spinal techniques are linked with less postoperative nausea, reduced need for strong opioids early on, and lower rates of breathing problems and blood clots in the legs and lungs ³. There is also a practical bonus I felt directly: because the legs are numb, pain relief carries over into the first hours of recovery, so I did not wake into a wall of pain the moment surgery ended.

None of this makes general anaesthesia a bad choice. It makes spinal the sensible default that has to be argued out of, rather than into.

What the spinal actually felt like

This was the part no leaflet captured for me, so I will be specific. I sat on the edge of the bed, curled forward over a pillow like a prawn, which opens the gaps between the spine bones. There was a cold wipe, then a sharp sting as local anaesthetic numbed the skin, the same feeling as the dental injections everyone knows. After that I felt pressure and a brief odd push, not pain, as the spinal needle went in ⁴.

Within a couple of minutes my legs began to feel warm, then heavy, then not mine at all. The strangest moment was being asked to shuffle across onto the operating table and finding my legs simply did not answer; the staff moved them for me.

The sedation came through the drip after that, and my memory of the operation itself is a few blurred fragments and then the recovery room. I never heard the surgery, which had been my real fear.

The role of nerve blocks and local anaesthetic

Alongside the main anaesthetic, many teams add a nerve block or inject local anaesthetic around the hip to manage pain afterwards. A nerve block targets specific nerves to numb a region of the leg, and it can keep working for hours after the spinal itself has worn off, smoothing the transition rather than leaving you to fall off a cliff when the numbness lifts ³.

Surgeons also commonly infiltrate local anaesthetic into the tissues around the new joint during the operation. The combination is part of why modern joint replacement leans less heavily on strong opioids than it once did, which in turn means less of the sickness and grogginess that opioids bring. When I asked about my own pain plan, this layered approach was what they described, and understanding it ahead of time made the first day far less alarming.

How the choice gets made

The decision is shared, but it is anchored by the anaesthetist’s pre-operative assessment, not by preference alone. Before surgery you will be asked in detail about your heart and lungs, your medicines, especially blood thinners, any allergies, previous anaesthetics, and problems like back surgery or spine conditions that can make a spinal harder to place ¹.

Some situations push toward a general anaesthetic, for instance if a spinal cannot be sited or if you simply cannot bear the idea of being awake. Others push firmly toward spinal, such as significant lung disease where avoiding a breathing tube is an advantage ³.

My own assessment took longer than I expected and covered medicines I had forgotten I took.

That conversation is also where the everyday risks were laid out: nausea, shivering, a sore throat from an airway, a post-spinal headache, and the muddled, foggy feeling that is more common in older adults after a general anaesthetic. Serious harm, such as lasting nerve injury or a severe allergic reaction, is rare ².

Knowing roughly when surgery makes sense in the first place is a separate question I worked through in my notes on the signs it is time for a hip replacement.

Questions worth asking before the day

If I had my time again, I would arrive with a short list rather than a vague dread. I would ask which anaesthetic they recommend for me specifically and why; whether I will be sedated and how deeply; whether a nerve block is part of the plan and how long its pain relief is expected to last; how the numbness will be checked before I am allowed to stand; and what they will do if the spinal does not take fully.

I would also mention any past bad reaction to anaesthesia early, because it changes the plan. Asking these did not make me a difficult patient. It made the morning feel like something I was part of rather than something happening to me, and that, as much as any drug, settled my nerves.

This is general information drawn from my own experience and the sources below, not medical advice. Your health, your medicines, and your anaesthetic plan are individual, so the choice belongs with the anaesthetist and surgeon who assess you in person.