A Fairfax County orthopedic surgeon whose office was vandalized and defaced with swastikas a week ago was struck on the head in the same office Sunday night by a man wielding a paperweight, Fairfax County police said yesterday.

Dr. James J. Scheiner, 41, whose office is at 8301 Arlington Blvd., was admitted to Jefferson Memorial Hospital in Alexandria for treatment of what a hospital spokesman called a probable concussion. Scheiner was listed in fair condition yesterday and was unavailable for comment.

Scheiner told police he was in a back room at his office in the Boulevard Medical Center when he was hit from behind by a man who appeared to be in his 20s. Police said no suspect has been apprehended.

On the weekend of March 25-26, vandals carved swastikas on the walls and office furniture in Scheiners office. Police estimated damage to X-ray equipment and other medical equipment at several thousand dollars. Police said there appeared to be no damage or theft at the doctor's office in Sunday's incident.

Scheiner has said his office has been broken into six times in the past nine years, but that the most recent vandalism was the first involving the Nazi symbol.