Hip fracture

Hip fracture
Classification and external resources
AP Hip projection demonstrating an Intertrochanteric fracture
ICD-10	S72.0
ICD-9	820
eMedicine	emerg/198 sports/48
MeSH	D006620

A hip fracture is a fracture in the proximal end of the femur (the long bone running through the thigh), near the hip joint.

The term "hip fracture" is commonly used to refer to four different fracture patterns and is often due to osteoporosis; in the vast majority of cases, a hip fracture is a fragility fracture due to a fall or minor trauma in someone with weakened osteoporotic bone. Most hip fractures in people with normal bone are the result of high-energy trauma such as car accidents.

In the UK, the mortality following a fractured neck of femur is between 20% and 35% within one year in patients aged 82, ± 7 years, of which 80% were women.^[1]

Classification

Many subtypes of fractures about the hip joint are colloquially known as 'hip fractures'. Although a true hip fracture involves the joint, the following four proximal femur fractures are commonly referred to as hip fractures. The differences between them are important because each is treated differently.

• Femoral head fracture denotes a fracture involving the femoral head. This is usually the result of high energy trauma and a dislocation of the hip joint often accompanies this fracture.
• Femoral neck fracture (sometimes Neck of Femur (NOF), subcapital, or intracapsular fracture) denotes a fracture adjacent to the femoral head in the neck between the head and the greater trochanter. These fractures have a propensity to damage the blood supply to the femoral head, potentially causing avascular necrosis. Widely used classifications were established by Pauwels and Garden.
• Intertrochanteric fracture denotes a break in which the fracture line is between the greater and lesser trochanter on the intertrochanteric line. It is the most common type of 'hip fracture' and prognosis for bony healing is generally good if the patient is otherwise healthy.
• Subtrochanteric fracture actually involves the shaft of the femur immediately below the lesser trochanter and may extend down the shaft of the femur.

Signs and symptoms

The classic clinical presentation of a hip fracture is an elderly patient who sustained a low-energy fall and now has pain and is unable to bear weight. On examination, the affected extremity is often shortened and externally rotated.

Risk factors

Most hip fractures occur as a result of low-energy falls in elderly patients. Falls are uncommon in young adults due to better balance and strength and when they do occur, they usually do not cause the "hip fracture" pattern of injury that is commonly seen in the elderly. It was formerly thought, but later disproved by Harvard medical scientists, that use of benzodiazepine increased the risk. A person with normal hips will not fracture them following a fall from standing. Hip fracture following a fall is likely to be a pathological fracture. The most common causes of weakness in bone are:

• Osteoporosis. Hip fractures are one of the most serious complications of osteoporosis; in fact a measure of success or failure of treatment of osteoporosis is the proportion of patients who sustain a hip fracture. Vitamin D deficiency is a common problem causing osteoporosis, and supplementing with vitamin D and calcium has been shown to reduce hip fractures by 43%.^[2]
• Homocysteine, a toxic 'natural' amino acid linked to the cause of heart disease, stroke and bone fractures, reduced by B-vitamins in this study^[3], it reduced the amount of hip fractures by 80% after 2 years. This was despite no differences in bone density and in the number of falls between the vitamin and the placebo groups.
• Other metabolic bone diseases such as Paget's disease, osteomalacia, osteopetrosis and osteogenesis imperfecta. Stress fractures may occur in the hip region with metabolic bone disease.
• Benign or malignant primary bone tumours are rare causes of hip fractures.
• Metastatic cancer deposits in the proximal femur may weaken the bone and cause a pathological hip fracture.
• Infection in the bone is a rare cause of hip fracture.

Another element in the risk of sustaining a hip fracture is the risk of falling. Fall prevention is an area if interest with concerns in the area of providing a safe environment for people at risk, custodial care, walking aids, medication issues etc. Hip protectors are padded plastic shields that can be placed over the trochanters of people at risk of falling or of sustaining a fragility fracture. However, they are not effective in reducing the likelihood of a hip fracture and compliance is poor.

In a study of 135,000 people 50 or older, those taking high doses of a proton pump inhibitor (PPI) (for example, Protonix, Prevacid, Prilosec) for longer than one year have been found to be 2.6 times more likely to break a hip. Those taking smaller doses for 1 to 4 years were 1.2 to 1.6 times more likely to break a hip.

Diagnosis

X-rays of the affected hip usually make the diagnosis obvious; AP and lateral views should be obtained.

In situations where a hip fracture is suspected but is not obvious on x-ray, a CT scan with 3D reconstruction may be helpful. MRI has gained importance in the diagnosis of occult fractures of the femoral neck. Within 24 hours changes can be seen on MRI. Bone scan is less useful because it may take up to 1 week to demonstrate changes especially in the elderly.

As the patients most often require an operation, full pre-operative general investigation is required. This would normally include blood tests, ECG and chest x-ray.

Femoral neck

Garden Type 1 Fractured Neck of Femur

Femoral neck fractures involve the narrow neck between the round head of the femur and the shaft. This fracture often disrupts the blood supply to the head of the femur.

Garden classified this fracture into four types:

• Type 1 is a stable fracture with impaction in valgus.
• Type 2 is complete but non-displaced.
• Type 3 is displaced (often rotated and angulated) with varus displacement but still has some contact between the two fragments.
• Type 4 is completely displaced and there is no contact between the fracture fragments.

The blood supply of the femoral head is much more likely to be disrupted in Garden types 3 or 4 fractures.

Surgeons may treat these types of fracture by replacing the fractured bone with a prosthesis arthroplasty. Alternatively the treatment is to reduce the fracture (manipulate the fragments back into a good position) and fix them in place with three metal screws.

A serious but common complication of a fractured femoral neck is avascular necrosis. The vasculature to the femoral head is easily disturbed during fractures or from swelling inside the joint capsule. This can lead to strangulation of the blood supply to the femoral head and death of the bone and cartilage.

Intertrochanteric

Intertrochanteric fractures occur between the greater and lesser trochanters. They are usually fixed with a sliding hip screw and plate. Healing is usually good when the patient is healthy.

Hip fractures are treated in one of two ways: Traction or orthopedic surgery.

Management

Most hip fractures are treated by orthopedic surgery, which involves implanting an orthosis. The surgery is a major stress on the patient, particularly in older people. Pain is significant, forcing the patient to remain immobilized. Since prolonged immobilization can be more of a health risk than the surgery itself, post-op patients are encouraged to become mobile as soon as possible, often with the assistance of physical therapy(physiotherapy).

If operative treatment is refused or the risks of surgery are considered to be too high the main emphasis of treatment is on pain relief. Skeletal traction may be considered for long term treatment. Aggressive chest physiotherapy is needed to reduce the risk of pneumonia and skilled nursing to try to avoid pressure sores and DVT/pulmonary embolism Most patients will be bedbound for several months. Non-operative treatment is no longer an alternative in developed countries with modern health care^{citation needed}.

Fractured neck of femur

Medial fracture in a 92-year-old woman

Fracture treated with cannulated screws

For low-grade fractures (Garden types 1 and 2), standard treatment is fixation of the fracture in situ with screws or a sliding screw/plate device. This treatment can also be offered for displaced fractures after the fracture has been reduced.

In elderly patients with displaced fractures many surgeons prefer to undertake a Hemiarthroplasty, replacing the broken part of the bone with a metal implant. The advantage is that the patient can mobilize without having to wait for healing.

Intertrochanteric fracture

Intertrochanteric hip fracture in a 17-year-old male

Fracture supported by dynamic hip screw

An intertrochanteric fracture, below the neck of the femur, has a good chance of healing. Treatment involves stabilizing the fracture with a lag screw and plate device to hold the two fragments in position. A large screw is inserted into the femoral head, crossing through the fracture; the plate runs down the shaft of the femur, with smaller screws securing it in place.

The fracture typically takes 3–6 months to heal. As it is only common in elderly, removal of the dynamic hip screw is usually not recommended to avoid unnecessary risk of second operation and the increased risk of re-fracture after implant removal. The most common cause for hip fractures in the elderly is osteoporosis; if this is the case, treatment of the osteoporosis can well reduce the risk of further fracture. Only young patients tend to consider having it removed; the implant may function as a stress riser, increasing the risk of a break if another accident occurs.

Hip replacement

In some hip fractures, the doctor completely removes the head and neck of the femur, and replaces it with a prosthetic implant.

Complications

Nonunion, failure of the fracture to heal, is common (20%) in fractures of the neck of the femur, but much more rare with other types of hip fracture. The rate of nonunion is increased if the fracture is not treated surgically to immobilize the bone fragments.

Malunion, healing of the fracture in a distorted position, is very common. The thigh muscles tend to pull on the bone fragments, causing them to overlap and reunite incorrectly. Shortening, varus deformity, valgus deformity, and rotational malunion all occur often because the fracture may be unstable and collapse before it heals. This may not be as much of a concern in patients with limited independence and mobility.

Avascular necrosis of the femoral head occurs frequently (20%) in fractures of the neck of femur, because the blood supply is interrupted. It is rare after intertrochanteric fractures.

Hip fractures rarely results in neurological or vascular injury.

Surgical

Deep or superficial wound infection has an approximate incidence of 2%. It is a serious problem as superficial infection may lead to deep infection. This may cause infection of the healing bone and contamination of the implants. It is difficult to eliminate infection in the presence of metal foreign bodies such as implants. Bacteria inside the implants are inaccessible to the body's defence system and to antibiotics. The management is to attempt to suppress the infection with drainage and antibiotics until the bone is healed. Then the implant should be removed, following which the infection may clear up.

Implant failure may occur; the metal screws and plate can break, back out, or cut out superiorly and enter the joint. This occurs either through inaccurate implant placement or if the fixation does not hold in weak and brittle bone. In the event of failure, the surgery may be redone, or changed to a total hip replacement.

Mal-positioning: The fracture can be fixed and subsequently heal in an incorrect position; especially rotation. This may not be a severe problem or may require subsequent osteotomy surgery for correction.

Medical

Many of patients are unwell before breaking a hip; it is not uncommon for the break to have been caused by a fall due to some illness, especially in the elderly. Nevertheless, the stress of the injury, and a likely surgery, does increase the risk of medical illness including heart attack, stroke, and chest infection.

Blood clots may result. Deep venous thrombosis (DVT) is when the blood in the leg veins clots and causes pain and swelling. This is very common after hip fracture as the circulation is stagnant and the blood is hypercoagulable as a response to injury. DVT can occur without causing symptoms. A pulmonary embolism (PE) occurs when clotted blood from a DVT comes loose from the leg veins and passes up to the lungs. Circulation to parts of the lungs are cut off which can be very dangerous. Fatal PE may have an incidence of 2% after hip fracture and may contribute to illness and mortality in other cases.

Mental confusion is extremely common following a hip fracture. It usually clears completely, but the disorienting experience of pain, immobility, loss of independence, moving to a strange place, surgery, and drugs combine to cause or accentuate dementia.

Urinary tract infection (UTI) can occur. Patients are immobilized and in bed for many days; they are frequently catheterised, commonly causing infection.

Prolonged immobilization and difficulty moving make it hard to avoid pressure sores on the sacrum and heels of patients with hip fractures. Whenever possible, early mobilization is advocated; otherwise, alternating pressure mattresses should be used.

• "Fractures of the Femoral Neck". Wheeless' Textbook of Orthopaedics. Duke University School of Medicine. http://www.wheelessonline.com/ortho/fractures_of_the_femoral_neck. Retrieved 27 January 2008. 
• "Intertrochanteric Fractures". Wheeless' Textbook of Orthopaedics. Duke University School of Medicine. http://www.wheelessonline.com/ortho/intertrochanteric_fractures. Retrieved 27 January 2008. 
• "Damage Control Orthopaedics: Patient Stabilization, Early Mobilization". 74th Annual Meeting of the American Academy of Orthopaedic Surgeons briefing. Medical News Today. 18 Feb 2007. http://www.medicalnewstoday.com/articles/63321.php. Retrieved 27 January 2008. 

Prognosis

Hip fractures are very dangerous episodes especially for elderly and frail patients. The risk of dying from the stress of the surgery and the injury in the first few days is about 10%. If the condition is untreated the pain and immobility imposed on the patient increase that risk. Problems such as pressure sores and chest infections are all increased by immobility. The prognosis of untreated hip fractures is very poor.

Post operation

Among those affected over the age of 65, 40% are transferred directly to long-term care facilities, long-term rehabilition facilities, or nursing homes; most of those affected require some sort of living assistance from family or home-care providers. 50% permanently require walkers, canes, or some other such device for mobility; all require some sort of mobility assistance throughout the healing process.

Among those affected over the age of 50, approximately 25% die within the next year due to complications such as blood clots (deep venous thrombosis, pulmonary embolism), infections, and pneumonia.

Patients with hip fractures are at high risk for future fractures including hip, wrist, shoulder, and spine. After treatment of the acute fracture, the risk of future fractures should be addressed. Currently, only 1 in 4 patients after a hip fracture receives treatment and work up for osteoporosis the underlying cause of most of the fractures. Current treatment standards include the starting of a bisphosphonate to prevent future fracture risk by up to 50%.

Epidemiology

Approximately 320,000 hospitalizations occur each year due to hip fractures in the US.

References

External links

• Orthopedics.com article on hip fractures
• Fractures of the Femoral Neck Wheeless Textbook of Orthopaedics
• Intertrochanteric Fractures Wheeless' Textbook of Orthopaedics
• National Hip Fracture Database National Hip Fracture Database
• Proximal femoral fracture Musculoskeletal Radiology of Fractures
• National Osteoporosis Society National Osteoporosis Society