Nearly one in five NHS organisations in England are formally rationing crucial hip and knee replacement surgeries by setting Body Mass Index (BMI) thresholds that patients must meet to qualify for an operation, according to a new analysis. The report from the charity Arthritis UK warns that this practice is creating a severe “postcode lottery” of care and leaving thousands in prolonged pain.
A Widespread and Growing Practice
Arthritis UK’s analysis of all 42 NHS Integrated Care Boards (ICBs) in England found that 31 have policies linking BMI to joint replacement surgery. Of these, eight ICBs—representing 19% of the total—are explicitly “rationing” by setting defined BMI cut-off points for surgical referral. A further 23 ICBs have policies that encourage or mandate weight loss to become eligible. Only 11 ICBs do not restrict or alter access based on BMI.
The prevalence of such policies has risen dramatically over the past decade. Research indicates that among their predecessor bodies, Clinical Commissioning Groups, the use of BMI policies rose from 13% in 2014 to 68% by 2021. Arthritis UK has expressed concern that these rules are often implemented “in a bid to cut waiting lists and costs” rather than being solely based on clinical evidence.
How BMI Policies Work and Their Impact on Patients
The ICBs justify the policies by highlighting surgical risks associated with obesity, such as higher chances of infection or wound healing problems. However, Arthritis UK states that significant risk is primarily linked to a very high BMI, and that policies have “been inappropriately used” to restrict patients with lower BMIs, such as 35.
For patients, the impact is profound. Deborah Alsina, chief executive of Arthritis UK, explained that joint replacement is often the final line of treatment for arthritis, after months or years of declining mobility. “Joints in need of replacement are incredibly painful and severely impact the ability of individuals to exercise which can lead to weight gain,” she said. “It is counterproductive to deny surgery that could get people back on the road to mobility.”
The charity also notes that BMI policies “are often ambiguous” and open to clinician interpretation, leaving patients without clear expectations. Furthermore, the weight management support needed to meet these targets is often inadequate. NHS weight loss programme waiting lists have ballooned, with some people waiting up to three years, while other services have closed entirely.
Critically, a UK cohort study published in *PMC*, analysing National Joint Registry data from 2005 to 2016, found no evidence to support clinically relevant worse outcomes for patients with a raised BMI following total knee replacement. The study concluded its findings do not support restricting referrals based on BMI alone.
The “Postcode Lottery” and Contradiction of National Guidance
Among the ICBs applying thresholds, there is “significant variation on the cut-off point,” creating stark geographical inequity. This patchwork of rules directly contradicts official guidance. The National Institute for Health and Care Excellence (NICE) explicitly advises that people with osteoarthritis should not be excluded from surgical referral solely for being overweight or obese, stressing decisions must be based on clinical need.
This contradiction is backed by research. A study in the *Journal of Health Services Research & Policy* found one-third of ICBs have policies that may prevent high-BMI individuals from being eligible, in conflict with NICE guidelines. Another study in *BMC Medicine* linked BMI policies to decreased surgery rates, particularly in more deprived areas, exacerbating health inequalities.
Medical Bodies Call for Policy Change
The findings have been endorsed by leading surgical organisations. Fergal Monsell, a surgeon and president of the British Orthopaedic Association (BOA), stated: “Denying someone the benefits of planned orthopaedic surgery based only on BMI is not evidence-based.” The BOA maintains that arbitrary barriers like BMI are not grounds for limiting referrals.
Mr Tim Mitchell, president of the Royal College of Surgeons of England, agreed, saying: “Supporting patients to reach a healthier weight before surgery can reduce complications, but BMI alone should not be a barrier to surgery. Surgical decisions must be made case by case.” He warned that delays can lead to loss of mobility and further health problems, and that ICB policies which penalise the less fit are “unfair and ignore clinical guidance.”
Both organisations, alongside Arthritis UK, highlight that while pre-operative health optimisation is beneficial, the evidence for short-term weight loss improving surgical outcomes is not strong. They argue that waiting in pain while trying to lose weight can actually reduce a patient’s overall fitness.
Arthritis UK is calling for an end to BMI policies that restrict access and has urged the Department of Health and Social Care to ensure efforts to cut waiting lists are not “to the detriment of a patient’s wellbeing.”