Gerhard Johannes Paul Domagk discovered Sulfanilamide arond 1936, and it became a soldiers saviour during the second world war, American soldiers were taught to pour Sulfa Powder on any open wounds from bullets or shrapnel to prevent infection, and sulfa powder/tablets where one of the main items a combat medic would have. Sulfa based drugs are still used today for antibacterial purposes. Although penicillin was discovered in 1906, it hadn't really become a widely used and recognized drug until a company called Pfizer picked up the drug and began perfecting it. Later the americans saw the potential of such a drug and commisioned 19 factories to produce the penicillin using Pfizers perfected techniques, and it is still one of the most commonly used antibiotics of today. Blood Plasma was discovered by a man called Dr. Charles Drew, and by 1940 was appointed for the Blood for Britain project to help all the wounded from the war, where 14,500 units of plasma where used in just 5 short months. these are just some of the important progressins in medicine that where forced into discovery during the second world war.
The Germans as far as I know learnt to use the metal stick inside the bone instead of long plaster cast support to make the bone heal better.