By some estimates, up to four people in five have one leg that is longer than the other. In most cases, this
leg-length discrepancy is not sufficiently pronounced to cause a problem. In others, it can cause the pelvis to tilt, which
leads to twisting of the spine and associated problems. Leg-length discrepancy can result from an anatomical or structural
shortening due to a fracture or an inherited abnormality. Or, it -may involve a functional difference in which leg lengths
may be equal, but a condition such as pronation (inward turn of the foot) causes one leg to strike first. With diagnosis and
appropriate treatment, either cause may be addressed so that it will cause no further strain and pain.
P.S. Many people do not have problems with leg-length discrepancy until a vigorous walking or running regimen
gives rise to leg pain as a result of the unequal distribution of pressure.