We use a slightly strange construction when we talk about fractured limbs. We make it sound as if it is the person's fault!
He broke his leg.
She broke her arm.
He's broken five ribs.
Obviously, the person did not injure those parts of their anatomy themselves (unless they are suffering from Munchausen's Syndrome), but that is how we generally say it.
Context will tell you if it means "We are talking about Gary and Gary now has a broken leg" or "We are talking about Gary who attacked Nigel and now Nigel has a broken leg, courtesy of Gary".
Gary attacked Nigel and broke his leg. Nigel is now in hospital.
Gary attacked Nigel and, in the process, broke his leg. Gary is now in hospital.