The foot and ankle research is reassuring. After a fusion operation on the back of the foot, the bones failed to join in 15.9% of people on these injections, compared with 20.2% of people not on them. After surgery to fix a broken ankle, people on the injections were less likely to need their metal plates or screws removed early. People living with obesity who took them were about half as likely to go on to need an ankle replacement. And in people whose ankles keep giving way, only 1.4% ended up needing surgery, compared with 7.8% of those not taking them. The fusion and broken-ankle results come from people with diabetes only.

But these studies were not the most reliable kind (randomised trials), and not every finding was good news. People with diabetes on these injections had more keyhole ankle operations (arthroscopy), and there may be a small rise in falls later on.

Many people who now come to a foot and ankle clinic take a weight-loss or diabetes injection, known as a GLP-1 medicine — such as semaglutide (Ozempic, Wegovy), tirzepatide (Mounjaro) or similar. They usually ask two questions: will this help my foot? and do I have to stop it before my operation?

This article focuses mainly on the first. On the second, the advice has changed recently and varies between hospitals, so much of what you read online may be out of date.

Research published in 2025 and 2026 is the first to look at the foot and ankle specifically.

Ankle arthritis

One large study compared people with ankle arthritis who took these injections with similar people who did not. Among people living with obesity (3,089 in each group), it found:

Over five years, people on the injections lost more weight than those who were not. Their BMI (a measure of weight for height) fell by 2.7, compared with 1.6.

In people with diabetes (8,117 in each group) the results were different. There was no difference in joint injections or joint replacement, but they were almost twice as likely to have keyhole ankle surgery (a higher rate: hazard ratio 1.9, likely range 1.2–3.2). They also lost less extra weight than the obesity group (BMI down by 2.1, compared with 1.7 in non-users). And, surprisingly, their long-term blood sugar level (HbA1c) improved slightly less than in people not taking the injections (down 5.5% compared with 6.0%) — a small but real difference.

A study in three hospitals followed more than 2,000 adults whose ankles kept giving way (chronic ankle instability), for two years. Seventy-one of them were taking semaglutide. Those people had better ankle function (16.3 points higher on a sports score and 9.3 points higher on a daily activities score), fewer repeat sprains, and 1.4% went on to need ankle surgery, compared with 7.8% of those not taking it. Every other ankle questionnaire used in the study also favoured the semaglutide group.

Weight loss explained only about a third of the benefit (31% and 34%). This raises the possibility that the drug also calms inflammation directly — possible, but not proven. Only 71 people were on the drug, so this is an early sign rather than a firm answer, and the researchers say a proper trial is needed.

This matters most if you already have an operation booked. The good news is that they do not seem to slow healing — and they may even help.

One review found only two studies, both in adults with diabetes. After a fusion operation on the back of the foot, the bones failed to join in 15.9% of people on the injections, compared with 20.2% of similar people not on them. The benefit was seen after fusions of the joints below the ankle (subtalar and triple fusion), but not after fusion of the ankle joint on its own. After surgery to fix a broken ankle, people not on these drugs were about twice as likely to need their metalwork removed within 30 days. Neither study found more infection or long-term problems. Both looked back at past records, with gaps in detail and other factors that may have affected the results — so this is encouraging rather than proven, and strictly it only applies to people with diabetes.

A separate review of 5,520 patients — two-thirds women, average age 55, most (77%) with a BMI over 30, and mostly having broken-ankle surgery (72%) or fusion for arthritis — agreed. Results were the same or better for people on the injections, and some studies also found less infection, fewer blood clots in the leg (DVT) and fewer heart problems.

Research across other bone and joint surgery shows the same: 35 studies found similar or fewer complications, fewer infections in joint replacements, shorter hospital stays and fewer returns to hospital. In knee replacement, infection happened in 1.5% of people on the injections, compared with 2.0% of those not on them — about a quarter fewer.

It would be easy to read all this and decide these injections are simply good for people having bone and joint surgery. The evidence is not strong enough to say that, for four reasons.

1. Most of the research looks back at past records

People who are prescribed these drugs may differ from those who are not in ways the researchers cannot fully account for. One review found that over half the studies on these drugs and arthritis were the weakest type of evidence.

2. Not every finding is good news

No one knows why people with diabetes on the injections had more keyhole ankle surgery. Results in spine surgery are mixed — some studies found more chest infections, kidney problems and bones failing to join in people on semaglutide for a long time.

3. There may be a link with falls

One review found a single result showing more injuries from falls later on. When you lose weight quickly, you lose some muscle as well as fat. If that makes you weaker or less steady, it matters — falls are a common cause of broken ankles. This is not proven, but it is the question I would most like to see studied.

4. We are not yet sure about the effect on bone

Reviews are mildly reassuring. One drug (liraglutide) lowered the risk of fractures and improved signs of new bone growth, and taking these drugs for more than a year improved bone strength in the spine and hip. But results differ between drugs, and healthy bone matters for fusion and fracture surgery.

The advice used to be to stop these injections for a week or more before an operation, because they slow down how quickly the stomach empties, which matters under anaesthetic. This advice is now being questioned. Recent UK guidance from anaesthetic experts suggests many people can keep taking them, and that stopping can upset blood sugar control — but practice still varies between hospitals, especially if you take the injection for weight loss.

So do not stop or carry on without checking: tell us which injection you take, and contact your hospital’s pre-assessment team several weeks before your operation. I am a foot and ankle surgeon, not an anaesthetist, so your anaesthetist will advise you.

• Tell us at your first appointment — which injection you take, the dose, how long you have been on it, and whether it is for diabetes or weight loss.
• Contact your pre-assessment team several weeks before your operation, not the week before.
• Do not stop the injection on your own — but do not assume you should keep taking it either. Check first.
• Do not start one just to lose weight for surgery without proper medical supervision. A higher BMI does increase the chance of an ankle replacement needing to be redone, but these are prescription medicines.
• Do not put off treating a painful foot for a long time while you wait to lose weight. Deformities get worse, and arthritis does not stand still.

If you take a weight-loss or diabetes injection and are thinking about foot or ankle surgery, bring the details to your appointment. We can plan around it properly — including whether waiting makes sense for you, or whether it would just delay a problem that will not get better on its own.

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