The proper definition is to look at the whole person and deal with the effects of the disease to the whole person. A broken ankle will incapacitate a person by various degrees depending on the severity and at what time you look. Alternatives would need to be worked out for bathing, transport to work, mobility with crutches, parking changes if required, work site modifications so that a person can get into their desk and have their foot up. There may well be some psychological problems related to having some lack of mobility and lack of being able to take care of things like laundry and so forth. This is a bit vague, but I hope you get the idea. The idea is that you are dealing with a person not a broken ankle.