The broken leg that 8-year-old Xzayvion Riley suffered four months before his alleged beating death in 2012 was caused by a “twisting” of the bone, not a fall, and would have been extremely painful, the doctor who operated on the Baton Rouge boy testified Wednesday.

Dr. Joseph Broyles testified at a hearing in the first-degree murder case of Michael Anthony Robertson, the boy’s father. His testimony came a day after the child’s mother, Lavaughn Riley, testified she heard Xzayvion’s leg pop in February 2012 when he tried to get away from Robertson — her then boyfriend — during what Riley described as horseplay.

Xzayvion told medical personnel he fell from a bunk bed, but Broyles said such a fall would not have caused the spiral fracture of the boy’s right femur. The femur is the largest, longest and heaviest bone in the human body, extending from the hip to the knee.

“No, it’s not consistent with a blunt force impact,” Broyles, an orthopedic surgeon at the Bone and Joint Clinic in Baton Rouge, testified of Xzayvion’s fracture while being questioned by East Baton Rouge Parish Assistant District Attorney Will Morris.

Broyles, however, acknowledged under questioning by Elizabeth Coe, one of Robertson’s court-appointed attorneys, that his medical report from 2012 said the leg break was consistent with a fall. The doctor said he no longer takes that position.

“A twisting injury causes a spiral fracture,” he said to Coe.

Broyles also stressed that Xzayvion would have been in extreme pain.

“Someone would immediately begin screaming in pain,” he said.

In addition to Riley testifying she heard the bone pop, the boy’s oldest sister has told investigators she heard her brother scream on that day in February 2012.

“Would somebody be able to hear that fracture?” Morris asked Broyles.

“Absolutely,” the doctor replied.

State District Judge Don Johnson is presiding over the hearing, which began Tuesday and will resume Thursday, to determine whether prosecutors will be allowed to introduce at Robertson’s trial evidence of incidents — including the February 2012 incident — leading up to Xzayvion’s death.

Robertson’s attorneys contend the alleged incidents are inadmissible and would only prejudice the jury.

Robertson, 48, and Riley, 34, both of Baton Rouge, are charged with first-degree murder in Xzayvion’s death. They were indicted together, but will be tried separately.

Another doctor, pediatric emergency room physician Dr. Brian Stout, testified Wednesday that Riley raised his hands to his own neck in August 2010 to show how Robertson allegedly choked him at that time.

“He basically brought his hands up to his neck like this,” Stout, a physician at Our Lady of the Lake Regional Medical Center, said while putting his hands over his neck. “I found it unusual. I’ve never had a patient demonstrate like that.”

Xzayvion was 6 when he was brought to OLOL in August 2010 by state investigators and his mother.

Stout said Xzayvion had abrasions on his neck and bruises on his arms, leg and groin area.

“I asked him who did this to him. He said, ‘Tony,’ ” the doctor testified.

Stout said he considered the boy’s injuries non-accidental.

A former state investigator testified earlier Wednesday that the boy told her Robertson choked and punched him and put his head into a toilet in August 2010.

“Xzayvion said his father, Tony, had choked him, punched him and put his head in a toilet,” Nikole Smith, a former state Office of Community Services investigator, testified.

OCS is now called the Department of Children and Family Services.

After photographing abrasions on Xzayvion’s neck and interviewing several people, including the boy, Smith said a safety plan was put in place disallowing Robertson from coming into the boy’s home or disciplining him. The plan was agreed to by the boy’s mother, Smith said.

Some time later, Smith said she was finally able to speak with Robertson, who indicated he possibly wanted to terminate his parental rights.

“He said he wanted to wash his hands of Xzayvion,” she testified.

Smith said she also interviewed Xzayvion’s oldest sister, who told her she witnessed Robertson punch her brother on more than one occasion.

Riley admitted Tuesday that, several days before Xzayvion broke his leg, she spanked him so hard with a belt that she left marks on him.

East Baton Rouge Parish Coroner Beau Clark concluded Xzayvion’s death was a homicide, finding the boy died of “overwhelming infection” caused by a ruptured bowel from blunt-force trauma to his abdomen. An autopsy also showed 60 external signs of recent and old trauma, including abrasions, bruises and a human bite mark.