The Shoulder Replacement Procedure: Anaesthetic, Incision, Duration and Hospital Stay

A shoulder replacement is major joint surgery, usually carried out under a general anaesthetic combined with a regional nerve block, in which the surgeon reaches the joint through a cut at the front of the shoulder, removes the worn surfaces, fits artificial metal and plastic parts, and closes up, taking roughly 1.5 to 2 hours for a straightforward primary case.¹ The detail of what is replaced depends on which of the three operations your shoulder needs, but the shape of the day is much the same.

The day itself was the part I had built up most in my head and, oddly, the part I remember least. I went to sleep with a worn-out joint and woke with a numb, pain-free arm in a sling, and the surgeon told me the hard work started the next morning. This is the plain account of what happens between those two moments. For where the procedure sits in the whole journey, start with the overview of what a shoulder replacement is; for what comes next, see recovery week by week.

What happens during a shoulder replacement?

The surgeon reaches the joint through the front of the shoulder, dislocates it to expose the worn ball and socket, removes the damaged surfaces, and fits the artificial parts before putting everything back together. The glenohumeral joint is a ball-and-socket: a worn ball on top of the arm bone (the humerus) and, in most cases, a worn socket (the glenoid) on the shoulder blade².

The core of the operation is the same across the three types. The muscles at the front are eased apart rather than cut through, the joint is opened, the diseased bone surfaces are cut and shaped to take the implant, and the components are fixed in place, some cemented and some press-fitted into the bone. The joint is then relocated, its stability and movement checked on the table, and the layers closed. It is careful, staged work, not a single dramatic act.

The anaesthetic: a general plus a nerve block

A shoulder replacement is usually done under a general anaesthetic, so you are fully asleep, very often combined with a regional nerve block that numbs the shoulder and arm for pain relief afterwards.¹ The block used is an interscalene block, placed at the side of the neck to switch off the nerves supplying the shoulder.

The block is the part patients tend not to expect. It can keep the whole arm numb and pain-free for many hours after you wake, which is why the first evening is often far more comfortable than people fear, and why the discomfort tends to arrive later as it wears off. Some centres use the block with sedation instead of a full general anaesthetic, depending on the patient and the anaesthetic team. The full account of both is in shoulder replacement anaesthesia.

How the surgeon reaches the joint

The common route is a deltopectoral approach: a cut at the front of the shoulder, running from near the collarbone down towards the upper arm, through the natural gap between the deltoid and the chest (pectoral) muscles.¹ Working through that gap lets the surgeon reach the joint without cutting across the main deltoid muscle.

Practically, that means the scar sits down the front of the shoulder rather than over the top of it, which surprises people who picture a wound on the point of the shoulder. Mine settled to a neat line I can only find when I look for it. Once the gap is opened, one of the muscles at the front (the subscapularis, part of the rotator cuff) is usually detached to get into the joint and then repaired at the end, which is one reason the early movement rules matter so much.

What is actually replaced

Exactly what is replaced depends on the type of operation: a total (anatomic) replacement caps the ball with metal and resurfaces the socket with plastic; a reverse replacement switches the ball and socket over; and a hemiarthroplasty replaces only the ball.³ The choice turns mostly on the state of the rotator cuff, not on age.

In a total replacement the natural anatomy is kept, so it depends on a working cuff to move the arm. In a reverse, a metal ball is fixed to the socket side and a plastic cup sits on the humerus, so the powerful deltoid muscle can lift the arm in place of a cuff that no longer works. A hemiarthroplasty leaves the natural socket in place and is used for some fractures and well-preserved sockets. Why the cuff decides between the first two, and how they compare on movement and durability, is set out in anatomic versus reverse shoulder replacement.

How long the operation takes

A straightforward primary shoulder replacement takes roughly 1.5 to 2 hours of surgery, and about 1 to 3 hours in total once anaesthetic, positioning and waking are added.¹ Complex cases, and revision operations where an earlier replacement is redone, take longer.

It is worth saying plainly that the length of the operation is not a report card. A longer time in theatre usually reflects the state of the joint, the bone quality, or the type being fitted, not a problem. For the person waiting outside, the wait always feels longer than the surgery; my family said the two hours felt like six.

The hospital stay

Most people stay in hospital for 1 to 2 nights after a shoulder replacement, though selected fitter patients now have it as a day case and go home the same day.⁴ The length of stay depends on your general health, the anaesthetic, and how the first hours go, rather than on the surgery alone.

The practical hurdles before you leave are ordinary ones: your pain is controlled on tablets as the block wears off, you can get in and out of the sling and manage it, you have eaten and passed urine, and the physiotherapist is satisfied you can move safely one-handed at home. A day-case pathway is only offered where the setup and the support at home make it sensible; it is not a target to push for.

Waking up and the first hours

You wake with the operated arm strapped in a sling across your body and, if you had a nerve block, a shoulder that is numb and pain-free for the first several hours. The sling holds the repaired tissues while they begin to heal, and the earliest gentle movements often start the same day or the next⁴.

Waking up was the moment the whole thing stopped being abstract for me. The arm did not feel like mine: heavy, numb, and utterly still in the sling, with no pain at all until the block faded that evening. Nobody had told me the block would wear off in a wave rather than all at once, so the tablets before it does matter. That first night is the start of the recovery, not the end of the operation; how the weeks unfold from there is in my shoulder replacement recovery, honestly.