The bone marrow aspirate injection Dwight Howard had on his knee Wednesday is described as “experimental” and based more in theory than “proven results,” doctors familiar with the procedure said.

Wednesday’s procedure is similar to the platelet-rich plasma treatment Howard underwent in December.

The big difference: The injection uses stem cells from his own bone marrow rather than plasma.

“It’s like injecting a teenager’s healing ability,” said Dr. Walter Lowe, who performed the 20-minute procedure.

Read more about this cutting edge procedure.