GARDNER, Mass. (AP) – Heywood Hospital in Gardner is reviewing policies and procedures after a surgeon operated on the wrong knee of a patient who needed arthroscopic surgery.

Hospital officials say they are investigating factors that may have contributed to the error.

Hospital President and CEO Daniel Moen apologized in a statement and said the hospital is committed to making sure it doesn’t happen again.

Neither the name of the orthopedic surgeon nor the patient were released.

The hospital acknowledged responsibility for the error and did not bill the patient, who is not expected to experience any long-term problems.