Two operations and less than 200 appointments had to be cancelled by hospital chiefs locally when junior doctors took strike action on Tuesday.
Ahead of the walk out, when junior doctors who are union members were only providing emergency care for 24 hours, patients were warned that some routine appotinments and surgery may have to be cancelled.
Letters were sent to patients who may have been affected ahead of the strike by West Herts Hospitals NHS Trust, which runs Hemel Hempstead, Watford and St Albans Hospitals.
There are around 330 junior doctors based across the three sites.
Following the industrial action, the government and British Medical Association have resumed talks over changes to contracts, which have sparked patient safety fears over longer working hours and a pay dispute.
Further action is planned for January 26 and a full walk-out is proposed for Wednesday, February 10.
A spokesman for the trust said: “Planning is already underway, including discussions to identify lessons learned from this week’s stike day.”