Joint replacement surgery unjustifiably delayed or denied for many people living with obesity
16 January 2025
One in ten people will need joint replacement surgery at some point in their life. But in some parts of England, patients with a higher body mass index (BMI) might be denied this treatment or have their access to it delayed.
National Institute of Health and Care Research (NIHR) funded researchers have shed light on the impacts of these policies. The researchers have renewed their call to remove the broad use of BMI as a barrier to joint replacement surgery.
Each Integrated Care System in England sets its own access rules for surgery. The majority do not limit access to surgery based on a patient’s BMI. However, at least ten per cent use strict policies which deny or delay access to surgery for patients living with obesity, unless exceptional circumstances can be demonstrated. Patients may be required to reach a certain BMI, or demonstrate that they have engaged with weight management programmes.
NIHR Applied Research Collaboration (ARC) West researchers collaborated with a local authority public health team and NHS commissioning group to evaluate such a policy introduced in 2017. This policy diverted patients referred for joint replacement surgery to a 12-week pathway offering support from a healthy lifestyles service. While generally acceptable to patients and professionals, uptake of the support was low. Data quality and linkage issues complicated the assessment of outcomes for patients who didn’t proceed to surgery.
These local findings raised questions over the wider impact of BMI threshold policies. NIHR ARC West supported Dr Joanna McLaughlin to analyse National Joint Registry data during her NIHR doctoral fellowship, completed in 2024.
The research revealed that BMI policies were associated with reduced surgery rates and higher use of private surgery, raising concerns that such policies worsen health inequalities. Interviews explored the persistence of these policies and revealed the financial drivers influencing decision-making.
Dr Joanna McLaughlin, NIHR Clinical Lecturer at the University of Bristol and study lead, said:
“National Institute for Health and Care Excellence (NICE) guidance is clear that BMI shouldn’t be used to restrict patients’ access to joint replacement surgery. Yet the use of BMI threshold policies continues. Some patients are able to resort to paying privately for surgery, but this is not an option for everyone, creating inequalities in our society.
“The work I’ve undertaken in my fellowship has shed light on why these policies persist. These are mainly shorter-term financial drivers, although evidence confirms that joint replacement surgery is cost-effective for patients living with obesity. The Lancet Diabetes & Endocrinology Commission reported this week that BMI is an inadequate measure of the health of any individual classified as living with obesity, further strengthening the case that BMI threshold policies need urgent reconsideration.
“We also found strong concerns that existing weight management support services are inadequate to ensure successful weight loss for all those affected by BMI policies. We welcome the indication in the Government’s recently published report on reforming elective care, that the Digital Weight Management Programme will be extended to support people waiting for knee and hip replacements in 2025/26.
“The removal of restrictive BMI measures still in use by any remaining Integrated Care Systems would immediately benefit thousands of patients. It will improve equitable access to care and is an important step to reduce healthcare inequalities for those living with obesity.”