Professor Zygmunt Krukowski was suspended from his job following an internal probe into his conduct at Aberdeen Royal Infirmary in May 2015.
His colleague Dr Wendy Craig was also under investigation but resigned shortly afterwards and is now believed to be working in the north-east of England.
Professor Krukowski specialised in thyroid disorders, including cancer, and was responsible for the team of medics in charge of caring for the Royal family when they fell ill while on holiday at Balmoral Castle.
The 67-year-old and Ms Craig were suspended from their duties at the city’s flagship hospital after raising concerns following dignity at work reviews which sets out conditions for employees.
The suspended surgeons felt that their efforts to raise their own dignity at work concerns had been stifled.
An investigation was also launched by the General Medical Council after damning reports on Aberdeen Royal Infirmary and other hospitals across the NHS Grampian region were published in December 2014.
One of the reviews, carried out by Healthcare Improvement Scotland (HIS), conducted a review of Aberdeen Royal Infirmary and also an unannounced inspection of services for older people in acute hospitals in the NHS Grampian region.
And a separate review from the Royal College of Surgeons looked at General Surgery.
Eight doctors were investigated as part of the NHS watchdog probe who have now all been cleared.
The cost of paying the consultant salaries, legal payouts and hiring locum doctors during the investigation, which has lasted almost two years, could cost the health board at least £5 million.
A source, who did not want to be named, said: “Ultimately, this is wasting millions which should be directed towards improved patient care.
“Instead, specialities are left uncovered with procedures carried out haphazardly by those not previously practising or fully trained in areas.”
The GMC investigation was triggered by one of the scathing reports which identified issues in the management of the busy hospital which was having an impact on patient safety and care.
Low morale was reported as well as the unprofessional behaviour of medical staff coupled with poor relationships between senior staff and management.
NHS Grampian chief executive Richard Carey took early retirement shortly before the reports were published and Bill Howatson also stepped own from his told as chairman.
Yesterday the GMC confirmed that their investigation had now concluded.
Niall Dickson, Chief Executive of the General Medical Council, said: “We have closed these cases based on a careful review of all the evidence available to us. That evidence included an independent report by the Royal College of Surgeons of England which was shared with us by the Health Board. Patient safety is our first priority and we acted appropriately in our duty to look at those concerns further.
“This was a complex investigation, made more so by the requirement to seek responses and advice from a range of experts and advisers, while respecting the administrative processes of other bodies which some doctors were engaged with.
“However, we are confident that we have closed this matter in an appropriate length of time while ensuring all concerned were treated fairly. We will continue to work with managers, doctors and others at Aberdeen Royal Infirmary to support high quality medical education and practice.”
Three of the surgeons investigated by the GMC are believed to be still working at the health board although five staff, including top surgeon professor Krukowski have left NHS Grampian.