Thousands of NHS knee replacement operations are cancelled at short notice every year, many for avoidable reasons, according to a new study published today [1 December]. This costs the NHS millions of pounds and increases waiting times for patients, many of whom are in severe pain.

The study, led by researchers at the University of Bristol’s National Institute for Health and Care Research (NIHR) Bristol Biomedical Research Centre (Bristol BRC), and sponsored by North Bristol NHS Trust, is published in The Bone & Joint Journal.

The NIHR-funded study collected information on the timing of, and reasons for, cancellation of total knee replacement surgery at 6 NHS hospitals in England, Scotland, Wales and Northern Ireland, over a period of 5 years between April 2018 and March 2023.

The study found at the 6 hospitals over the 5 years 17,223 total knee replacement operations were completed and 9,403 cancelled – more than previously thought. This is the first study to measure total knee replacement cancellations across more than one hospital.

Each operation cancelled at short notice costs the NHS a lost tariff of between £6,500 and £11,000. This adds up to over £15.5 million across the 6 hospitals, over 5 years.

A quarter of the cancellations were less than 24 hours before surgery, and nearly one third were within 2 to14 days. Cancellations the day before, or on the same day as surgery, can leave empty operating theatre spaces which are difficult to fill. Rescheduling these operations adds to already lengthy NHS waiting lists.

Cancelled surgery and increased waiting times can reduce patients’ quality of life and leave them feeling rejected. Patients on the waiting list experience a significant decrease in quality of life after 6 to 12 months of waiting for total knee replacement surgery – a quarter say they are waiting in a state “worse than death”, according to previous studies.

Lack of available hospital beds and patients being unfit for surgery were the most common reasons for short-notice cancellations. Many of these cancellations could have been avoided with advance planning.

Heart problems, infections and wounds were the main health reasons for cancelling surgery. With the right medical care while people wait for their operation, many patients could be supported to be medically fit for surgery, and cancellations avoided.

The scale of this problem is huge. Knee replacements are one of the most common types of surgery, with over 110,000 total knee replacements performed yearly in the UK. More than 3 million people are currently waiting more than 18 weeks for non-urgent NHS surgery.

This highlights an urgent need for efficiency programmes in the NHS, and UK-wide healthcare planning for patients on waiting lists, to prevent cancellations.

Dr Mark Eveleigh, Consultant Anaesthetist at Gloucestershire Hospitals NHS Foundation Trust, said: “Cancelled operations aren't just about wasted resources. Each cancellation statistic represents a patient who has often uprooted their entire life to get into hospital, followed the preparation advice to the letter, arranged transport and found someone to look after loved ones, frequently at great cost to themselves.

“So for us then not to do the operation after they have gone through all that is, in my mind, unforgivable.

“We should strive for zero avoidable cancellations, and projects like this are the first step to realising that across the NHS. Until we know what drives cancellations, we cannot realistically expect them to simply stop happening.”

Michael Whitehouse, Professor of Trauma and Orthopaedics at the University of Bristol, and a co-author on the paper, explained: “This work has demonstrated a substantial and underappreciated problem for the large number of patients waiting for joint replacement surgery.

“Pathways patients have to follow are often complicated and difficult to navigate, even to get to the point of being put on a waiting list for surgery. As highlighted by our patient contributor to this research, cancellations are not benign temporary blips and can lead to substantial unwarranted delays.

“The Getting It Right First Time programme highlights the need for ring-fenced beds to protect activity such as joint replacement, yet the most common institutional reason we found for cancellation was the lack of a bed for the patient to go into.

“The common clinical reasons for cancellations are issues that can be identified in advance, and this would allow the operating slot to still be used productively to provide care for another patient, if properly designed care pathways are put in place to better support our patients to the benefit of all.”

Peter Aitken, patient and public contributor involved in the research, said: “My knee replacement operation was originally booked for November 2023, but was cancelled after my pre-op appointment because of blood-thinning medication I was taking at the time.

“It was rescheduled for March 2025, and I attended hospital on the day. But, after a wait of seven and a half hours, when I was ready with my gown on, I was told at the eleventh hour that the operation would have to be cancelled because they ran out of time.”

Dr Wendy Bertram, study lead and Senior Research Associate in Musculoskeletal Health Services Research at the University of Bristol, added: “This study shows knee replacement operations are cancelled much more often than we thought.

“There are a lot of statistics in our publication – each and every one represents a human being who has been waiting a long time for a procedure to relieve their pain. Many people wait a year or more, and endure a life put on hold, not able to make plans or do the things they enjoy.

“The light at the end of the tunnel is their operation, but cancellation quickly snuffs this out. We can do better for these people. So we are using the information from this study to build programmes that will prevent cancellation and support people while they wait.”

Health Minister Karin Smyth said: “This study exposes the shocking scale of cancelled knee operations — with thousands of patients left waiting in pain. Each cancellation represents not just a statistic, but someone's quality of life being put on hold, which is unacceptable.

"That is why we are investing in our NHS to reduce cancellations, including by shortening hospital stays to free up beds, building new surgical hubs, and giving patients more control over their appointments through tools like the NHS App. When patients are in control of when their treatment takes place and informed about how to be ready for surgery, rather than the ‘like it or lump it’ approach of the NHS in the past, they are far less likely to cancel last minute — better for them and better for the NHS.

"We are also rolling out the NHS Federated Data Platform to 85% of acute trusts by March 2026, which will give frontline staff a complete picture of their operational systems in one place, helping them plan staffing and resources more efficiently to meet demand. We know there’s more to do, but our investment and modernisation agenda is building an NHS fit for the future.”