Cost-cutting plans to slash the number of people eligible for hip and knee replacements have been criticised by surgeons.
Three Clinical Commissioning Groups in Worcestershire plan to only treat the most severe cases where pain interferes with daily life and ability to sleep.
Bosses said changing the scoring system to cut operations will save £2m a year.
The Royal College of Surgeons said the proposals have "no clinical justification".
Redditch and Bromsgrove, South Worcestershire, and Wyre Forest are the CCGs behind the proposals, estimated to lead to around 350 fewer operations a year.
The plans would focus on treating "severe to the upper end of moderate" cases, and people who are obese with a body mass index of 35 or over needing to lose 10% of their weight unless their problems were very severe.
'Barriers to care'
CCG documents said a "patient's pain and disability should be sufficiently severe that it interferes with the patient's daily life and/or ability to sleep".
Stephen Cannon, vice president of the Royal College of Surgeons, said the scoring system used, known as the Oxford scoring system, "should not be used to create barriers to care".
Analysis by BBC health reporter Philippa Roxby
Many local NHS commissioning groups in England are introducing these kinds of cost-cutting measures.
Harrogate, Vale of York, Shropshire and the south coast of Kent are all imposing similar restrictions on non-emergency surgery.
Some are asking patients to lose weight or stop smoking before they can be considered for an operation.
Other NHS bodies are restricting patient access to some treatments, surgery, expensive drugs and IVF.
Demand for new hips has risen across all ages groups and particularly in the under 60s, NHS figures for England show.
This is mainly because new replacements now last for much longer than before, surgeons say.
But with demand only likely to grow with an ageing population, and the money to pay for them getting increasingly scarce, NHS rationing of hip and knee replacements may well become more common.
A spokesperson for NHS Redditch and Bromsgrove CCG, on behalf of the three groups, said: "If a patient feels that they require this surgery but do not meet these criteria, there is a clear appeals system."
Gordon Wainwright, from Malvern, is waiting for a hip operation and said he is concerned how eligibility will be judged.
"If you are filling in the Oxford test, as we all do, if you want to get the op done you're probably going to not be totally truthful because you want to get your operation done," he said.