Why is limping so common, especially in the elderly? Dirschl : There are four basic reasons why people develop a limp. Something is painful, stiff or weak—or one leg is substantially different. That last option is responsible for only a small percentage of limps, so I will focus on the first three. Any one of these, or any combination, could cause someone to limp. Let’s begin with pain. In younger people the primary cause is physical trauma, such as sports injuries or motor vehicle accidents. The most common cause of pain in older people, however, is arthritis, which causes pain as well as stiffness. If someone already has a limp, inflammation makes it even more pronounced. Pain can affect any of the limping-related joints: hip, knee, ankle or foot. Discomfort in any of those locations is common and is likely to be experienced by more and more people as they age. Each specific location causes a slightly different kind of limp. Diagnosing the cause of a limp is ba...