Femoral Neck Fracture

Introduction

The femur bone (thigh bone) is the strongest bone in the body; it extends from the hip joint to the knee joint and is responsible for weight-bearing function and gait stability. The femur bone consists of proximal and distal ends and a femoral shaft. The proximal end of the femur bone consists of the femoral head, femoral neck, and greater and lesser trochanter. The femoral neck is pyramid shaped and, at the proximal end, attaches the femoral head and the femoral shaft and is considered the weakest part of the femur bone. The femoral artery is a major branch of the external iliac artery that supplies the femur bone. The main source of vascular supply to the femoral head is the medial femoral circumflex artery; the shaft and the distal end are supplied by the perforating branches of the deep femoral artery. The femur bone is located within the anterior compartment of the thigh muscles and mainly helps in hip flexion and knee extension.

What Is a Femoral Neck Fracture?

A break or discontinuity in the neck of the femur bone (one or two inches from the hip joint) is called a femoral neck fracture. It is one of the common types of hip fractures, mainly seen in elderly individuals, especially women with low bone density. In young adults, it may be seen due to high-energy trauma or in individuals not being used to strenuous activity. Some femoral neck fractures may also be associated with femoral shaft fractures.

What Are the Types of Femoral Neck Fractures?

Based on the fracture location along the femoral neck, these fractures can be classified as;

• Subcapital Fractures: Fractures located at the junction of the head and neck of the femur bone.

• Transcervical Fractures: Fractures located at the midportion of the femoral neck.

• Basicervical Fractures: At the base of the femoral neck.

Subcapital and transcervical fractures are intracapsular fractures, and basicervical are considered intracapsular or extracapsular fractures.

What Are the Causes of Femoral Neck Fractures?

Some causes of femoral neck fractures include the following;

• In young individuals, especially athletes, it may occur due to repetitive activities or overuse, leading to stress and the development of tiny cracks in the bone that extend over time.

• These fractures can occur due to high-energy trauma such as vehicle accidents, collisions, and falls during sports activities such as football, hockey, rugby, etc.

• In elderly people with osteoporosis (weak and brittle bones), it may occur due to tripping or falls on the hip joint.

What Are the Signs and Symptoms of Femoral Neck Fractures?

Some signs and symptoms of femoral neck fractures include;

• Severe stabbing pain in the area immediately following the injury.

• Pain in the groin area and in front of the thighs.

• Difficulty in bearing weight on the affected side.

• Pain increases on rotating the hip.

How Is a Femoral Neck Fracture Diagnosed?

A complete medical history is noted, followed by a thorough physical examination to check for the extent of injuries, deformity, skin breaks, bruises, and lacerations. Range of motion and touch sensation is also assessed. Blood tests, urine tests, chest X-rays, and ECG investigations are advised in the case of older patients to facilitate pre-operative and post-operative management. Radiological investigations include:

• X-rays of anterior-posterior (AP) views, lateral views, or sometimes X-rays of the full length of the femur bone are recommended to determine the type of fracture and its extent and to rule out any associated fractures. Stress fractures can be identified by the fracture line on the superior aspect of the femoral neck, and compression fractures usually occur on the inferior aspect of the femoral neck. Loss of contour can be observed from the medial edge of the femoral neck to the superior pubic ramus. Asymmetry can be noted in the lateral aspect of the femoral head or neck.

• Computed tomography (CT Scan) or magnetic resonance imaging (MRI) is recommended in cases wherein the fractures cannot be clearly determined by normal radiographs. CT scan is helpful in diagnosing the presence of displacement or degree of comminution of fractures. An MRI scan is usually accurate, especially in determining occult fractures (hidden or fractures that are not visible on a radiograph). Occult fractures are identified by a fracture line at the cortex, surrounded by a zone of inflammation in the medullary cavity.

How Is a Femoral Neck Fracture Managed?

The aim of the treatment is to restore the femur bone's normal function, avoid complications, and promote faster healing. Non-operative management is rarely employed in the treatment of femoral neck fractures. It is considered for comfort care in patients at high risk and non-ambulatory (unable to walk around) patients. The main focus must be on rest to prevent the aggravation of the condition through exercises and physical activities. Emphasis on early mobilization is essential to avoid complications such as deep vein thrombosis and embolism.

• Open reduction and internal fixation (ORIF) is preferred in young patients and patients with displaced femoral neck fractures. Sliding hip screws are used in case of displaced fractures, and cannulated screws can be used in non-displaced fractures.

• In elderly patients with displaced fractures, treatment is decided based on age and activity level. In the case of patients who are physically less active, hemiarthroplasty is preferred. During this surgery, the damaged femoral head is replaced by an implant which helps to stabilize the femur and also restores the function of the hip. This is performed by hollowing out the femur bone from the inside so as to place the metal stem or the prosthesis firmly.

• In the case of fully active individuals, total hip replacement is preferred over hemiarthroplasty. During this procedure, the femoral head and the hip socket are removed and replaced by metal implants. It is considered more resilient but is associated with a risk of dislocation compared to a hemiarthroplasty. Medications include non-steroidal anti-inflammatory drugs such as Acetaminophen, Ibuprofen, etc., to relieve pain and inflammation, followed by physical therapy and rehabilitation exercises.

What Are the Complications of Femoral Neck Fractures?

Some of the complications of femoral neck fractures include:

• Severe femoral neck fractures can cause damage to the blood vessels, leading to poor or lack of blood supply to the bone resulting in the death of the bone tissues, called avascular necrosis or osteonecrosis.

• Malunion (abnormal) or nonunion of the fractured fragments following treatment.

• Dislocation of the fractured bone may occur following a failure of hip arthroplasty.

• Long-term inactivity may lead to the formation of blood clots called deep vein thrombosis.

Conclusion

A fracture of the neck of the femoral bone is a femoral neck fracture; it is characterized by pain in the groin area and thighs and difficulty in weight bearing. It mainly occurs in young adults due to trauma or in athletes, due to repetitive physical activities, or due to falls in elderly individuals with osteoporosis. It is usually managed surgically by open reduction, internal fixation, or partial or complete hip arthroplasty, followed by rehabilitation. Proper emphasis on physical therapy and limitations following the surgery must be taken for a successful recovery.