Actually, for folks above a certain age ~ especially women, although maybe the fact that women live so much longer skews the statistics ~ a broken hip is very serious, and while it may not be cited as the "cause" of death, it is often followed by death not long afterwards.

My great-grandmother lived into her early nineties and was quite healthy and independent until she broke her hip (walking down the icy front steps in winter, setting out on her daily one-block walk to 6am Mass). She passed away within less than a month.