Patients looking for the safest care should hope for a surgeon aged between 35 and 50, according to a study published in the British Medical Journal today.

The findings suggest that people undergoing surgery were at higher risk of complications with inexperienced surgeons but also with those who have been in practice for 20 years or more.

The Royal College of Surgeons put the phenomenon down to evolving surgical techniques and technology, saying that older surgeons need to "constantly reinvent themselves" to keep up.

A research team, led by doctors Antoine Duclos and Jean-Christophe Lifante from the University of Lyon in France, studied 3,574 operations to remove a patient's thyroid gland by 28 surgeons. Two major complications were measured 48 hours after surgery and again at least six months after surgery.

Professor Mike Larvin, consultant general surgeon and director of education at the Royal College of Surgeons, said: "This study shows the importance of lifelong learning – something the RCS supports by running courses for trainees and consultants. We have also set out professional development for medical revalidation, a system of five-year checks on competence, which starts at the end of this year."