Newswise — LOS ANGELES — Feb. 27, 2018 — Orthopaedic surgeon Robert Klapper, MD, co-director of the Joint Replacement Program at Cedars-Sinai, spends his days repairing worn-out hip joints. But examining the hip joint of an animal extinct for more than 12,000 years presented an entirely new challenge—and shed light on a long-running debate within paleontology about saber-toothed cats.

Klapper is working with the paleontologists at the La Brea Tar Pits and Museum to unravel the mystery of how these giant cats lived and roamed. Using Cedars-Sinai’s most advanced CT scan machines, Klapper studied the pelvis and femurs of an extinct cat. "The most modern technology allowed these bones to speak to us, and they had a lot to say," Klapper said.

One bone specimen held particular interest for Klapper. Originally, scientists speculated the bone’s owner died of infection. But Klapper’s analysis of the CT scan showed that the animal was born with dysplasia, an abnormal development of the hip joint. 

That finding, and the fact that this particular cat lived into adulthood, revealed that the animal had been limping since birth and survived only because it lived with a pack. The finding answered a long-debated question over whether saber-toothed cats hunted alone or in packs.

Now Klapper will use the cat's CT scans to create a prosthetic hip joint that will help him treat dysplasia in the tallest human patients. "What if you’re 7'1"? We don't have prostheses that fit that height," Klapper said.  "What we’re doing is taking a CT scan to build the anatomy and then a prosthesis."

Officials at the La Brea Tar Pits and Museum are continuing their collaboration with Klapper and are developing an exhibit based on his findings. 

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