Much of the trial has focused on Kelsey's broken legs.
Sullivan examined Kelsey on May 2, 2005, and found she had suffered spiral cracks to both shin bones. He is a children's orthopedic surgeon at the University of Oklahoma.
He testified Monday he thinks the legs were broken at different times. He looked at Kelsey after she was brought in by her paternal grandmother, Kathie Briggs.
The doctor said a spiral fracture can happen when the bone is twisted as someone slings a child by the leg in anger. He said three other experts at OU confirmed his finding of abuse.
"Dr. Sullivan, any doubt in your mind this was child abuse?” prosecutor Pattye High asked.
"Absolutely none,” he said.
Two broken legs
Jurors were told last week that Kelsey was taken to the emergency room of a Shawnee hospital on April 14, 2005, after supposedly falling at the zoo while with an aunt. She was diagnosed then with a sprained right ankle.
Her mother reported she had fallen at the zoo while wearing flip-flop shoes with platform soles, according to testimony.
Doctors at a Shawnee clinic on April 25, 2005, found both legs were broken after Kelsey had trouble walking. The doctor who put her in casts concluded she could have broken her right leg at the zoo and broken her left leg overcompensating, according to testimony. That doctor, Andrea Barrett, who has not testified, put Kelsey's legs in casts April 26, 2005.
In his testimony Monday, Sullivan said the right leg could not have been broken from such a fall. He said there is nothing in the professional medical literature that would support a theory the second leg broke when Kelsey overcompensated while trying to walk.
Prosecutors allege Kelsey's mother covered up the abuse, like the broken legs, by blaming injuries on falls and other accidents. Defense attorneys contend the broken legs cannot be blamed on Kelsey's mother because many people were around the girl during the time period she was hurt.
Raye Dawn Smith and Porter wed on April 18, 2005, at the courthouse in Shawnee. They divorced after Kelsey's death.
Porter, 27, is serving 30 years in prison and testified last week as a prosecution witness. He once was accused of sexually assaulting and murdering Kelsey but pleaded guilty to enabling child abuse. He told jurors he did not harm Kelsey but saw his ex-wife abuse her three times.