What Is It?

The hip is the joint between the upper end of the thighbone (femur) and its socket in the pelvis. When a hip fractures (breaks), the injury is always in the femur. The upper end of the femur can fracture in any one of the following places:

• The head of the femur - The rounded surface at the very end of the bone that fits into a socket in the pelvis.

• The neck of the femur - A somewhat horizontal stretch of bone at the top of the femur that gives this bone the shape of an inverted "L".

• Between or below the greater and lesser trochanters - The femur has a natural bend at the lower boundary of the hip, angling toward the knee. At this bend, two bony humps protrude along the outside edge of the femur. These ridges are the greater trochanter and lesser trochanter.

Falling is the most common cause of hip fractures. Usually, this occurs in people older than 50. Older people are at risk of hip fractures because of osteoporosis, a disease that weakens bones and may be age-related. A hip also may be fractured during trauma, such as an automobile accident.

The severity of the fracture is determined by the degree to which the bone has moved from its original position (its displacement). Fractures can be:

• Nondisplaced, in which the bone has cracked but not separated

• Minimally displaced, in which the bone has shifted slightly along or away from a break

• Displaced, in which a part of the bone has become completely detached

Symptoms

A hip fracture can cause hip pain, swelling, bruising or a deformed look to the hip. It may be difficult to move the hip, especially to turn the foot outward or bend at the hip. The fracture may make the hip seem too weak to lift the leg. People usually have pain in the groin when they put weight on the hip. Walking or even standing can cause the fracture to extend further, which may worsen the pain. In severe cases, a person with a hip fracture is in too much pain to move. In rare cases, usually in people who are bed-bound and do not put weight on their hips, a hip fracture may not cause any symptoms.