Neck of femur fracture overview

# Overview
Neck of femur fracture is an orthopedic emergency. Femoral neck fractures are a commonly encountered injury in orthopaedic practice and result in significant morbidity and mortality. It is becoming increasingly common due to aging population. United states has highest incidence of hip fracture rates worldwide. Women are more commonly affected than men. It is essential to recognize specific fracture patterns and patient characteristics that dictate the use of particular implants and methods to effectively manage these injuries. Neck of femur fracture must be differentiated from other causes of acute hip pain, restriction of movements, and deformity such as intertorchanteric hip fracture, osteoarthritis, avascular necrosis, septic arthritis, trochanteric bursitis, slipped capital femoral epiphysis and acute synovitis. Garden and Pauwels classification systems has remained the practical mainstay of femoral neck fracture characterization that help dictate the appropriate treatment. Operative interventions include in situ fixation using cannulated cancellous screws, closed or open reduction and internal fixation using sliding hip screw, hemiarthroplasty, and total hip arthroplasty.

# Historical Perspective
In 1600s, Ambrose Pare, a French surgeon described the neck of femur fracture. In 1825, Sir Astley Paston Cooper delineated between intracapsular fractures from other fractures about the hip. In 1858, Von-Langen Beck, the German surgeon performed the first internal fixation of the femoral neck fracture with silver-plated screws. In 1932, Johansson devised a guide pin for easy positioning of the nail. In 1936, Knowle advocated multiple threaded pins for stabilization of neck of femur fractures. In 1936, Mc Murray performed oblique osteotomy for non union fractures. In 1986, O.N. Nagi, V.K. Gautham and S.K. Smarya introduced cancellous screw fixation and fibular graft for comminuted femoral neck fractures.

# Classification
There are multiple classifications available for neck of femur fracture. The most common classification systems for neck of femur fracture include Anatomical, Garden's, Pauwel's and AO/OTA classification.

# Pathophysiology
The pattern of fracture and degree of comminution are the resultant of several factors or variables such as the nature of injury, the bone quality, the age and weight of the patient, the energy involved, and the position of the hip and leg at the time of impact. Various combinations of these variables lead to a variety of different fracture patterns.

# Causes
The most common cause of neck of femur fracture is trauma in form of motor vehicle accident and fall.

# Differentiating Neck of femur fracture from Other Diseases
Neck of femur fracture must be differentiated from other causes of acute hip pain, restriction of movements, and deformity such as intertorchanteric hip fracture, osteoarthritis, avascular necrosis, septic arthritis, trochanteric bursitis, slipped capital femoral epiphysis and acute synovitis.

# Epidemiology and Demographics
The incidence of neck of femur fracture is approximately 146 per 100,000 individuals worldwide. Neck of femur fracture showed bimodal distribution among women and a unimodal distribution among men. Men had an increasing incidence of fractures until 50 to 60 years of age, followed by a decline in incidence. Women showed a peak incidence between 20 and 30 years of age. The median age at diagnosis is 57.7 years  for women and 46.8 years for men. There is no racial predilection to neck of femur fracture. Women are more commonly affected by neck of femur fracture than men. Surgical management for neck of femur fracture is done in 92.1% of the cases.

# Risk Factors
Common risk factors in the development of neck of femur fracture include age, female gender, and health conditions.

# Screening
The risk of neck of femur fracture due to osteoporosis is threatening, affecting one out of two postmenopausal women and one out of five men older than 50 years. The 10-year risk for osteoporosis-related neck of femur fracture in a 65-year-old white woman with no other risk factor is 9.3%. According to the guidelines of USPSTF, all women  65 years old along with women < 65 years old with a high risk of fracture are the target of screening for osteoporosis, but there is not any recommendation to screen men for the disease. Dual energy x-ray absorptiometry (DXA) of both hip and lumbar spine bones and quantitative ultrasonography of the calcaneus are two major methods suggested for screening osteoporosis.

# Natural History, Complications, and Prognosis
If left untreated, 30% of patients with neck of femur fracture may progress to develop non union and avascular necrosis. Common complications of neck of femur fracture include infections and thromboembolism. Prognosis is generally poor, and the 1 year mortality rate of patients with neck of femur fracture is approximately 25-30%.

# Diagnosis

## Diagnostic Study of Choice
Computed tomography (CT) is the gold standard test for the diagnosis of neck of femur fracture. Computed tomography (CT) with two-dimensional reconstruction in the sagittal and coronal planes provides more detailed information than radiographs. CT helps in fracture fragment orientation and surgical planning.

## History and Symptoms
A positive history of pain, deformity, and restricted hip movements is suggestive of neck of femur fracture.

## Physical Examination
Patients with neck of femur fracture usually appears well. Physical examination of patients with neck of femur fracture is usually remarkable for swelling, tenderness, bruises, ecchymosis, deformity  and restricted range of motion of the leg.

## Laboratory Findings
There is a limited role for laboratory tests in the diagnosis of neck of femur fracture; however, elderly women may have some abnormal laboratory findings suggestive of osteoporosis.

## Electrocardiogram
There are no ECG findings associated with neck of femur fracture.

## X-ray
Radiographic imaging is important in diagnosis, classification, treatment and follow-up assessment of neck of femur fracture. The routine minimal evaluation for neck of femur fracture must include two views - an anteroposterior (AP) view and lateral view.

## Echocardiography and Ultrasound
There are no echocardiography/ultrasound findings associated with neck of femur fracture.

## CT scan
Computed tomography (CT) with two-dimensional reconstruction in the sagittal and coronal planes provides more detailed information than radiographs. CT also helps in fracture fragment orientation and surgical planning.

## MRI
MRI helps in identifying occult fracture of neck of femur.

## Other Imaging Findings
There are no other imaging findings associated with neck of femur fracture.

## Other Diagnostic Studies
There are no other diagnostic findings associated with neck of femur fracture.

# Treatment

## Medical Therapy
The mainstay of treatment for neck of femur fracture is surgery. Non-operative management is reserved for a very small proportion of patients.

## Interventions
There are no interventions associated with neck of femur fracture.

## Surgery
Surgery is the mainstay of treatment for neck of femur fracture. It is a surgical emergency as the risk of avascular necrosis and non union increases as time passes by. The decision-making process for determining the best surgical procedure uses both the fracture type and the patients activity level to choose between internal fixation and arthroplasty. The types of surgery include femoral pinning, sliding hip screw and prosthetic replacement.

## Primary Prevention
There are no established measures for the primary prevention of neck of femur fracture. Healthy diet and regular exercises like running and weight lifting help decrease the chances of fracture.

## Secondary Prevention
Effective measures for the secondary prevention of neck of femur fracture include early detection and management of osteoporosis.