An independent review of the work of Julian Upton, 62, who was employed at the Musgrove Park Hospital in Taunton for 38 years, concluded that his management of patients was "not adequate".
The review, published yesterday, was ordered by the Taunton and Somerset NHS Trust after colleagues raised concerns about Mr Upton's work last October. Mr Upton retired on medical advice in March.
Of 1,200 patients whose cases have so far been examined, 45 were identified as requiring further surgical treatment and a further 22 needed further investigation.Some of the affected patients are seeking compensation.
Edward McNally, chief executive of the trust, said yesterday: "The trust regrets that some patients have received treatment which was not adequate for their condition, and the trust apologises to those patients for any anxiety or distress caused by that treatment."
The review would take six months to complete, Mr McNally said, by which time 2,000 case records would have been examined.