The high cost of malpractice insurance and billing restrictions in Massachusetts are causing increasing numbers of young doctors to leave the Bay State after they complete their training, according physicians, hospital administrators and a recent poll.

The Harvard-affiliated teaching hospitals report that this year, as many as 21 of 26 graduating residents in orthopedics, obstetrics, and neurosurgery--high liability specialties--plan to leave the state or continue their education rather than practice medicine in Massachusetts.

"There are very few residents who would consider staying here," said Waldo Floyd, a 31-year-old resident in orthopedics at Massachusetts General Hospital (MGH) who will graduate this year and practice in Georgia.

The development appears to be part of a two-year trend, according to physicians and administrators at MGH, Brigham and Women's Hospital, and Beth Israel Hospital. Before last year, most graduating residents remained in the area, said spokesman for the hospitals.

None of the five residents in orthopedic surgery graduating this June from training programs at Harvard affiliated hospitals plan to remain in Massachusetts permanently, according to the program's spokesman, Linda Perullo.

"They probably would want to leave," Perullo said. "It used to be that this was a mecca. Now they're thinking about leaving."

Additionally, none of the orthopedic residents who graduated in 1985 have established practices in Massachusetts, according to recently collated data, said MGH Assistant Clinical Professor of Orthopedic Surgery Edwin T. Wyman. In 1984, more than one-quarter of all orthopedic residents chose to work in the state.

Four of the 10 obstetricians who will graduate in June from residency programs at Harvard-affiliated hospitals plan to begin practices in Massachusetts, and none of the four neurosurgical residents scheduled to conclude their four-year residencies this year plan to stay, according to spokesmen for the hospitals' programs.

Harvard administrators and physicians yesterday attributed the development to concerns over Massachusetts' troubled medical malpractice situation.

The medical malpractice crisis reached a head last February when several hundred Massachusetts physicians in the three high-liability specialties refused to treat patients or accept new cases. Physicians planned the job action to protest skyrocketing malpractice insurance premiums and a Massachusetts law that prohibits doctors from charging more than health insurance allocates. Harvard doctors generally did not participate in the job action because the university offers them substantially less expensive insurance.

"They can't afford to practice here. They wouldn't have enough to live on," Perullo said. Perullo said that the so-called balanced billing law prevents Massachusetts doctors from passing the higher insurance costs on to their patients.