Hip Fractures
Background: Fracture of the hip can have devastating consequences. This is particularly true in older persons, who often suffer this calamity. Aside from considerable risks of morbidity and death, hip fracture causes loss of mobility and can significantly reduce the patient's quality of life. Athletes rarely return to their premorbid level of activity and ability following a hip fracture.
Pathophysiology: The healthy femur, with angular anatomy. Hip fractures involve fracture of any aspect of proximal femur, from the head to the first 4-5 cm of the subtrochanteric area.
The hip joint is a large ball-and-socket synovial joint. It is enclosed in a thick, synovium-lined articular capsule that extends from the acetabulum to the intertrochanteric line anteriorly. Posteriorly it covers the proximal half to two thirds of the femoral neck. Contiguous with and reinforcing this capsule are 3 strong ligaments: iliofemoral (Y ligament of Bigelow), pubofemoral, and ischiofemoral. The joint is supported further by numerous large muscles that cross it.
Vascular supply
Vascular supply to the hip is tenuous. It consists of perforating branches of the medial and lateral circumflex femoral arteries, the inferior and superior gluteal arteries, and the posterior branch of the obturator artery. These branches form the 3 main vascular structures that supply the femoral neck and head: the vascular ring around the base of the neck, ascending cervical interosseous and intracapsular vessels that emanate either partially or entirely from the vascular ring, and vessels of the ligamentum teres. In most people, the foveal artery that enters the femoral head with the ligamentum teres is insufficient to nourish the entire head.
Fractures of the neck, especially displaced fractures, often lead to avascular necrosis of the femoral head from disruption of interosseous vascular channels and intracapsular vessels, which lie against the periosteum of the femoral neck.
Classifying fractures
Hip fracture classifications most often are based on their anatomic locations: head, neck, intertrochanteric, trochanteric, and subtrochanteric. Subclassification represents significant differences in emergent referral and treatment.
In classifying the fracture, note whether it is intracapsular or extracapsular, as this has a significant impact on healing. Femoral head and neck fractures are considered intracapsular, while trochanteric, intertrochanteric, and subtrochanteric fractures are considered extracapsular. Intracapsular hip fractures, like all other intracapsular fractures, frequently have complicated healing. Surrounded by the thick capsule, these fractures are separated from adjacent soft tissue and its abundant capillaries and have impaired callous formation. Thus, nonunion is an added complication of these fractures.
Femoral head fractures
These usually are associated with hip dislocations. Superior femoral head fractures normally are associated with anterior dislocations, while inferior femoral head fractures are associated with posterior dislocations.
- Type 1 - Single fragment fractures
- Type 2 - Comminuted fractures
Femoral neck fractures
- Type 1 - Stress fractures or incomplete fractures
- Type 2 - Impacted fractures
- Type 3 - Partially displaced fractures
- Type 4 - Completely displaced or comminuted fractures
Intertrochanteric fractures
- Type 1 - Single fracture line; no displacement; considered stable
- Type 2 - Multiple fracture lines or comminution; displacement; unstable
Trochanteric fractures
- Type 1 - Nondisplaced fractures
- Type 2 - Displaced fracture; greater than 1 mm displacement for greater trochanteric fractures and greater than 2 mm displacement for lesser trochanteric fractures
Subtrochanteric fractures
- Stable - Bony contact of medial and posterior femoral cortices
- Unstable
Frequency:
In the US: Hip fracture occurs in approximately 80 per 100,000 persons or approximately 250,000 persons each year. Incidence of hip fracture increases with age; with current population projections, the number of fractures per year is expected to double by 2040. US frequency, when age and sex are adjusted, is highest in the world.
Internationally: Western Europe and New Zealand also have reported high rates. Lowest rates occur in South African Bantu people and in East Asian countries.
Mortality/Morbidity:
- Reported overall mortality rate of hip fractures is 15-20%, yet in older persons that can increase to 36% over the year following hip fracture. Rate of mortality is greatest in the first few months following injury but remains high for up to 1 year. It then returns to the same rate for age- and sex-matched people without hip fracture.
- Morbidity associated with hip fracture is staggering, especially in older persons. Morbidity from immobilization includes development of deep vein thrombosis, pulmonary embolism, pneumonia, muscular atrophy, and associated rehabilitation problems. Morbidity from surgical procedures includes anesthetic morbidity, postoperative infection, loss of fixation, malunion or nonunion, and all possible complications associated with immobilization as outlined above.
- Hip fracture resulting from major trauma often is associated with other bone and soft-tissue injuries, intra-abdominal and intrapelvic injuries, major blood loss, head and neck injuries, and other extremity injuries. Morbidity associated with an inability to return to a prefracture level of mobility results in a loss of independence, reduction in quality of life, and depression, particularly in older persons.
Race: Incidence of hip fracture is 2-3 times greater in whites than in nonwhites, primarily because of the increased rate of osteoporosis in whites.
Sex:
- Rate of hip fracture is 2-3 times greater in women than in men. At least 75% of all hip fractures occur in women.
- Lifetime risks of hip fracture in white women and men are 15% and 5%, respectively.
- Femoral neck fractures are more frequent in women than men by about 4:1. Intertrochanteric fractures are more frequent in women than men by about 5:1
Age:
- Rate of hip fracture increases with age; after age 50 years, it doubles with each decade. Nearly 50% of all hip fractures occur in adults older than 80 years. Hip fracture at a young age is not common and is usually the result of a major traumatic event or, rarely, is related to bone pathology.
- Femoral head fractures are more common in younger patients, because the same mechanism of injury is more likely to cause femoral neck fracture in older persons.
- Trochanteric fractures are uncommon and affect younger patients more often than older persons.
- Femoral neck fractures are rare in younger patients; the average age is 74-78 years.
- Intertrochanteric fractures also are rare in younger patients; the average age is 75-81 years.
- Subtrochanteric fractures have a bimodal age distribution and are seen most often in those aged 20-40 years in association with high-energy trauma and in patients older than 60 years.
History:
- In older persons, hip fracture most often results from a simple fall; in a small percentage, it occurs spontaneously in the absence of a fall.
- Patient complains of pain and inability to move the hip.
- With stress fractures in young athletes and nondisplaced fractures, patient may complain of pain in hip or knee and may be ambulatory.
- Patient may have a history of other osteoporotic fractures, such as Colles or vertebral fractures.
Physical:
- In patients who experienced trauma, perform a primary survey and stabilize as needed.
- Take a detailed secondary survey because of the high likelihood of other associated injuries. As many as 69% of patients with femoral head fracture-dislocations had major associated injuries, including other extremity injuries, intra-abdominal or intrapelvic injuries, neck injuries, and head injuries.
- Pay particular attention to vital signs and secondary manifestations of shock such as changes in skin, mental status, and urine output. Hip fractures are associated with blood volume losses of up to 1500 cc.
- Inspect and palpate for deformity, hematoma formation, laceration, and asymmetry.
- Observe the natural position of the extremity, as this alone often indicates the type of injury the patient has sustained.
- Femoral head fracture: Most often, this occurs as a result of hip dislocation; therefore, the position of the extremity is abduction, external rotation, and flexion or extension for anterior dislocation. With posterior dislocation (most common type), the extremity is held in an adducted and internally rotated position.
- Femoral neck fracture: Extremity is held in a slightly shortened, abducted, and externally rotated position, unless the fracture is only a stress fracture or severely impacted. In this case, the hip is held in a natural position.
- Intertrochanteric fracture: Extremity is held in a markedly shortened and externally rotated position.
- Subtrochanteric fracture: Proximal femur usually is held in a flexed and externally rotated position.
- Trochanteric fracture
- No deformities are noted on observation.
- Apply lateral to medial pressure on hips through greater trochanters.
- In assessing range of motion (ROM), first test external and internal rotation with extremity in extension. If the patient has a fracture, especially a displaced one, the remainder of ROM exam is extremely painful, of limited diagnostic use, and potentially dangerous. If the patient has pain with the initial ROM exam, obtain x-ray prior to completing.
- Perform a detailed distal neurovascular exam.
- If patient is a trauma victim, assess for pelvic fracture by stressing pelvis anteriorly to posteriorly through iliac crests and symphysis pubis, and laterally to medially through iliac crests.
Causes:
- in young persons, trauma associated with significant kinetic energy is required to cause a hip fracture. For example, 75% of all femoral head fractures, more common among young patients, occur as a result of motor vehicle accidents.
- In older persons, more than 90% of these fractures result from trauma or torsion associated with a minor fall. They also can occur in the absence of an obvious traumatic event.
- Osteoporosis greatly increases risk of fracture.
- Other risk factors for hip fracture include the following:
- Dementia
- Cigarette smoking
- Institutional living
- Maternal history of hip fracture
- Previous hip fracture
- Previous Colles or vertebral fracture attributed to osteoporosis
- Physical inactivity
- Low body weight
- Tall stature
- Alcohol abuse
- Impaired vision
- Use of psychotropic medications and drugs that decrease bone mass, including furosemide, corticosteroids, thyroid hormone, phenobarbital, and phenytoin
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