The family members of a handicapped man are asking for the public's help in identifying an assailant they believe pushed him from his wheelchair and caused his hip to break.

Alan Halderman, 56, of Newport Beach was coming home from the pharmacy in his electric wheelchair when he and another man had some kind of altercation about 3:15 p.m. Monday in front of the Old Spaghetti Factory on the Balboa Peninsula, his sister Sharon Frost and brother Larry Halderman said.

Alan Halderman had a stroke three years ago and is unable to write or speak, but can answer yes or no to questions, Frost said.

Using those types of questions, Alan Halderman described his attacker as a white man, with a medium build and height, and possibly sandy-colored hair.

Initially Alan Halderman's injuries seemed to be just a scraped knee, but it ended up being a broken hip, Frost said. His family also believes he was struck twice in the head.

Although he used a motorized wheelchair as transportation, he was able to walk before his alleged altercation and now he cannot.

A stroke in 2009 paralyzed his right arm, and after Monday's incident, Halderman's movement is limited to some use of his left arm, Frost said.

"He can't even move himself to the edge of the bed," she said.

Family members said the motive is unknown, but said none of Alan Halderman's belongings seemed to be missing.

He underwent surgery Wednesday at Hoag Hospital to repair his hip.

Newport Beach police said anyone with information is asked to call the department at (949) 644-3717.

lauren.williams@latimes.com

Twitter: @lawilliams30