In fact, no evidence supports withholding joint replacement from obese people, even on utilitarian grounds, says Nicholas Finer, a consultant in obesity medicine at Addenbrooke's Hospital, Cambridge.
For knee replacement, there is "no evidence that age, gender, or obesity is a strong predictor of functional outcomes," while a UK health technology assessment of hip replacement concluded that obese patients could benefit from surgery and are not noticeably at increased operative risk.
Another study concluded that relative body weight alone does not influence the benefit derived from hip replacement surgery, he writes.
"Since obesity does not increase the risks or diminish the benefits of joint replacement, the trust's decision to deny such treatment seems to be based on prejudice or attribution of fault, or both," he says. "Logically extended, such a policy would deny treatment to, among others, smokers, most patients with HIV infection, and those who sustain sports injury."
Rationing joint replacements is also false economy and potentially damaging, writes retired doctor, Martin McNicol in another letter.
Delaying operations on "punitive" grounds may increase long term costs. Personal experience shows that delaying joint replacement surgery causes deterioration of functional capacity, which is difficult or impossible to reverse after later operation. "This is rationing by any other name," he says.