During war medical advancements happen often faster than if during times of peace. With so many wounded to treat it becomes inevitable that progress would be made in medical treatments.
While antibiotics had been around for some time there had not been widespread use of them until WW2 and antibiotics are credited for saving millions of lives during the war and also lead to creations of new treatment methods.
With thousands of soldiers receiving burn wounds and gruesome injuries the treatment of burns and life altering injuries changed during WW2 to the point that many soldiers would have complete recoveries from burns with minimal scarring and plastic surgeries became less invasive and repairing gruesome injuries once thought unrepairable now started to become a reality as new techniques were found to deal with these life altering injuries.
Rehabbing took major strides forward as again new ways of rehabbing soldiers appeared reducing the time they would spend in hospitals and recovery clinics.
German doctors started using metal plates to to repair broken bones as it was found that using metal plates to stabilize the break reduced the recovery by almost half.
There were many other advances in medicine and these are but a few of those advances.
Please feel free to add to this list.