Hip Fracture
Normal Anatomy
The hip joint functions as one of the most important joints in the human body. Designed for both mobility and stability, the hip allows the entire lower extremity to move in three planes of motion, while providing an important shock absorption function to the torso and upper body. The hip is a ball and socket joint, uniting the femur (thigh bone) with the pelvis. As a result of this configuration, the leg moves forwards and backwards, side to side, and rotates to the right and left.
The pelvis features two cup-shaped depressions called the acetabulum, one on either side of the body. The femur, or thigh bone, is the longest bone in the body and connects to the pelvis at the hip joint. The head of the femur, shaped like a ball, fits tightly into the acetabulum, forming the ball and socket joint of the hip.
Embedded within the acetabulum of the pelvis lies an important structure known as articular cartilage; this cartilage has two very important functions. First, the smooth, low friction surface of the cartilage allows the hip joint to move freely in all planes of movement. Second, the articular cartilage cushions the hip during weight bearing activities, providing an important shock absorption function to the entire lower extremity.
The hip joint also features a complex system of ligaments that provide stability for the pelvis and lower extremity. The ligaments of the hip joint connect the femur to the pelvis and are essential to keeping the hip from moving outside of its normal planes of movement.
The muscles of the hip joint have dual responsibilities. They provide the dynamic functions necessary to raise and lower the lower extremity as well as the stabilizing functions required during standing, walking, or other weight-bearing exercises. This complex system of muscles works synergistically to provide the power for the hip to move in all directions, as well as to stabilize the entire lower extremity during weight-bearing activities.
Pathology
Hip fractures are breaks in the upper part of the thigh bone (femur) and are the second-most common break in the human body after wrist fractures under the age of 75 years and the most common fracture after 75 years of age. Hip fractures usually occur in older patients with weaker bone. The upper part of the femur underneath the ball and socket joint will separate from the lower part of the femur. These fractures usually occur from a fall from a standing height. Younger patients can also get hip fractures, but these usually occur as a result of high-energy trauma such as a motor vehicle or motorcycle accident. X-rays show the break, its location and pattern. A physical examination is important to check for injuries to other structures, such as muscles or nerves.
Treatment
Fractures of the hip are usually complete fractures and often require surgery. Surgery ensures that the bone is aligned in the correct position assuring bone healing and that the patient can begin to put weight on the leg immediately to prevent the leg from getting weaker from lack of use. Therapists help patients perform exercises to improve motion, strength, and to get the patient back to walking normally and with confidence. If the upper part of the femur (femoral neck) is broken but still in good alignment, pins can be placed in the bone through small incisions. If the femoral neck is broken severely, the patient may need a partial hip replacement in order to stabilize the thigh bone so the patient can walk right away. When the region of the femur at the base of the femoral neck or just below is broken, it is referred as an intertrochanteric or subtrochanteric femur fracture, respectively. These surgeries used to be done with long incisions using plates and screws. Now special slender metal rods can be placed inside the bone through small incisions. After surgery, therapists work with the patient to start moving the hip, working on strengthening the muscles around the hip and leg, and to begin walking again. Once the fracture is healed, most patients are able to return to their activities with or without limitations, based on their pre-injury level of ambulation and function.