According to police paperwork, Angela Goss, 28, dragged the child across a hallway floor after the girl urinated on herself and the floor.
Investigators said while Goss was dragging the girl, the child hit her leg on an entertainment center, causing her to break her left tibia.
Investigators said after the child was hurt, Goss went to a methadone appointment instead of taking her child to a hospital.
"It's heartbreaking to know that a child is suffering through this painful injury and is not going to get the attention she needs," said Trooper John Matchik.
Goss spoke to Channel 11's Timyka Artist on Tuesday, who denied the accusations.
"I take care of my kids. I love them. I'm a mom. That's all there is to it," said Goss.
Matchik said the child was taken to the hospital four hours after suffering the injury. He said the girl's grandmother took her to see a doctor while Goss waited in the car.
"She wanted the grandmother to go inside with the 4-year-old while she waited outside and passed out in the car," Matchik said.
Goss is facing aggravated assault and child endangerment charges.