Hip fracture

This article is about proximal femoral fractures. For fractures of the hip bone, see Pelvic fracture.

Hip fracture

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

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.

• 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. It may be classified into four Pipkin's degrees.
• Femoral neck fracture (sometimes Neck of Femur (NOF), subcapital, or intracapsular fracture)
• 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 unnaturally, externally rotated compared to the unaffected leg.

Risk factors

Hip fracture following a fall is likely to be a pathological fracture. The most common causes of weakness in bone are:

• Osteoporosis.
• Homocysteine, a toxic 'natural' amino acid linked to the cause of heart disease,
• 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.

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 not obvious on x-ray, an MRI is the next test of choice. If an MRI is not available or the patient can not be placed into the scanner a CT may be used as a substitute. MRI sensitivity for radiographically occult fracture is greater than CT. Bone scan is another useful alternative however substantial drawbacks include decreased sensitivity, early false negative results, and decreased conspicuity of findings due to age related metabolic changes 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

File:Femoral neck fracture, right hip.jpg

Femoral neck fracture three months after surgery.

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.

British orthopaedic surgeon Robert Symon Garden described a classification system for this type of fracture, referred to as the Garden classification and consisting of four grades:

• Type 1 is a stable fracture with impaction in valgus.
• Type 2 is complete but non-displaced.
• Type 3 is partially displaced (often externally 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 metal screws. Common practice is to use repair Garden 1 and 2 fractures with screws, and to replace Garden 3 and 4 fractures with arthroplasty, except in young patients in whom screw repair is attempted first, followed by arthroplasty if necessary. This is done in an effort to conserve the natural joint since prosthetic joints ultimately wear out and have to be replaced.

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.

Intertrochanteric Fracture Classification EVANS CLASSIFICATION

    Type 1 : Fracture line extends upwards and outwards from the lesser trochanter (STABLE)
    1A: Undisplaced two fragment fracture
    1B: Displaced two fragment fracture
    1C: Three Fragment fracture without posterolateral support, owing to displacement of greater trochanter fragment.
    1D: Three Fragment fracture without medial support, owing to displacement of lesser trochanter or femoral arch fragment.
    1E: Four Fragments fracture without posterolateral and medial support.
    Type 2 : Fracture line extends downwards and outwards from the lesser trochanter 

Ramadier's classification

a: Cervico-trochanteric fractures
b: Simple pertrochanteric fractures
c: Complex pertrochanteric fractures
d: Pertrochanteric fractures with valgus displacement
e: Pertrochanteric fractures with an intertrochanteric fracture line
f: Trochantero-diaphyseal fractures
g: Subtrochanteric fractures 

Briot's grading of diaphyseo-trochanteric fractures

A Evans' reversed obliquity fracture
B "Basque roof" fractures
C Boyd's "steeple" fracture
D Fractures with an additional fracture line ascending to the intertrochanteric line
E Fractures with additional fracture lines radiating through the greater trochanter

Ender's classification

Trochanteric eversion fractures
-1 Simple fractures
-2 Fractures with a posterior fragment
-3 Fractures with lateral and proximal displacement
Trochanteric inversion fractures
-4 With a pointed proximal fragment spike
-5 With a rounded proximal fragment beak
-6 Intertrochanteric fractures
Subtrochanteric fractures
-7 and 7a Transverse or reversed obliquity fractures
-8 and 8a Spiral fractures

Boyd and Griffin's classification

Linear intertrochanteric line fractures
Intertrochanteric line fractures with comminution
Subtrochanteric fractures
Fractures of the trochanteric region and the proximal shaft 

Tronzo's classification

Type 1: Incomplete fractures
Type 2: Uncomminuted fractures, with or without displacement; both trochanters fractured
Type 3: Comminuted fractures, large lesser trochanter fragment; posterior wall exploded; neck beak impacted in shaft
Type 3 Variant: As above, plus greater trochanter fractured off and separated
Type 4: Posterior wall exploded, neck spike displaced outside shaft
Type 5: reverse obliquity fracture, with or without greater trochanter separation 

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 the elderly. 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 rehabilitation professionals such as occupational therapy and physical therapy (physiotherapy). Skeletal traction pending surgery is not supported by the evidence.

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 rehabilitation and nursing to avoid pressure sores and DVT/pulmonary embolism Most people will be bedbound for several months. Non-operative treatment is no longer an alternative in developed countries with modern health care.

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 or intracapsular 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.

Traction is contraindicated in femoral neck fractures due to it affecting blood flow to the head of the femur.

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

Main article: 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 result 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 common 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 delirium or accentuate pre-existing 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.

References:

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 cruches 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 reduce future fracture risk by up to 50%.

Epidemiology

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

Alcohol use

An international study of almost 6,000 men and 11,000 women found that persons who reported that they drank more than 2 units of alcohol a day had an increased risk of fractures compared to non-drinkers. For example, those who drank over 3 units a day had nearly twice the risk of a hip fracture.

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