The Royal College of Surgeons (RCS) has said it does not support Bupa's medical reviews for knee surgery because it has no input or control over the process.
It also expects the private medical insurer to publicly publish the results of any research it conducts regarding the variation in knee surgery rates across the country.
Bupa has reiterated that its process has been backed by the General Medical Council and adheres to clinical best practice.
And the provider added that it conforms to National Institute for Health and Clinical Excellence (NICE), something disputed by the RCS.
COVER has seen a letter from Professor John Stanley, vice president of the RCS, sent to the British Orthopaedic Association (BOA), one of the surgeons' representative bodies disputing the Bupa review process, questioning the scheme.
"The College does not support any third party review of a consultant's decision to treat a patient," Prof. Stanley wrote.
"There are very clear clinical guidelines laid down by NICE and by individual specialty associations and there is no need for a decision to be reviewed by another consultant or anyone else, unless it is at the request of the patient or the consultant.
"If a surgeon is found to be not working to professional guidelines then that is a matter for their medical director," he added.
Prof. Stanley continued that he "would not be happy" to support Bupa's medical review process for knee arthroscopy "as we have no input or control over the Bupa process", however he was happy to "agree completely with the principle of clinical best practice and full adherence to clinical guidelines".
As a result, Prof. Stanley added: "The College welcomes any clinical investigation of variation in practice as long as it is open and transparent and there is an acknowledgement at the outset that variation in numbers of people being offered and undergoing treatment can mean that there is under provision in certain areas as well as possible over provision in others.
"We would support BOA involvement in Bupa's research and would expect Bupa to make public the results of their investigation and open it up for peer review once it is completed."
Bupa did not directly address the question of whether it would publish the findings of its research, but was pleased that following previous discussions the RCS "agrees completely with the principle of clinical best practice and full adherence to clinical guidelines."
Dr Annabel Bentley, medical director of Bupa Health and Wellbeing, said: "There appears to be a fundamental misunderstanding by some doctor groups about the purpose of our medical review process for knee arthroscopy.
"The process enables us to ensure we only pay for knee arthroscopies that represent clinical best practice and are therefore covered by our members' policies.
"We will not pay where there is clear clinical evidence that a knee arthroscopy would be ineffective for the patient's condition, for example for some cases of osteoarthritis.
"Our review process supports clinical best practice and is in line with GMC and NICE guidance. It does not, as has been suggested, go against these," she added.
Dr Bentley also confirmed that the clinical decision about treatment is between the doctor and the patient.
