Hip Fractures

Overview

Definition

A hip fracture is a disruption in the cortex of the femur at the hip joint, either between the greater and lesser trochanters (intertrochanteric) or at the femoral neck.

Anatomy

The hip is a ball-and-socket joint made up of the femoral head and acetabulum (socket). Blood supply to the femoral head is from the circumflex artery.

Classification

Hip fractures are classified by anatomic location and fracture type. Recognizing these fractures is important for surgical management.

• Intracapsular (femoral neck) hip fracture:
  • Pauwel classification is used to divide fractures into 3 groups based on the angle of the fracture from the horizontal plane:
    • Type I: < 30 degrees
    • Type II: 31–50 degrees
    • Type III: > 50 degrees
  • Garden classification is more commonly recognized:
    • Type 1: impaction fracture
    • Type 2: complete fracture, nondisplaced
    • Type 3: complete fracture with partial displacement
    • Type 4: complete fracture with complete displacement
  • Intracapsular fractures have higher rates of nonunion and malunion.
  • More likely to lead to avascular necrosis (AVN) of the femoral head
• Extracapsular (intertrochanteric) hip fracture:
  • 2018 AO/OTA is the standard classification for fractures used by trauma surgeons and physicians dealing with musculoskeletal orthopedic trauma care:
    • A1: stable, fracture has 2 parts
    • A2: unstable, comminuted fracture
    • A3: unstable, reverse/transverse fracture
  • Extracapsular fractures have a lower risk of complications.

Epidemiology

• Prevalence: 
  • One of the most frequent fractures in patients presenting to EDs
  • 15% of women and 5% of men will sustain a hip fracture in their lifetime due to osteoporosis.
• Incidence:
  • Approximately 550/100,000 women per year in the US
  • Approximately 200/100,000 men
• Average age of presentation: 80 years
• 5% of affected individuals have no history of trauma.

Etiology

• High-energy trauma in healthy adults: 
  • Motor vehicle accidents involving passengers or pedestrians
  • Fall from a significant height
  • Victim of violence or gunshot
• Low-energy trauma in the elderly due to falls and/or osteoporosis:
  • Risk factors for falls:
    • Prior history of falls
    • Gait abnormalities
    • Use of walking aids
    • Vertigo
    • Parkinson’s disease
    • Epilepsy
  • Risk factors for osteoporosis:
    • Smoking
    • Older age
    • Hormone deficiency (menopause in women and hypogonadism in men)
    • Use of steroids (glucocorticoid therapy)
    • Low body weight
    • Smoking
    • Excess alcohol intake
• Pathological fractures caused by a disease process (not related to trauma):
  • Osteoporosis
  • Paget’s disease of bone
  • Bone tumors: 
    • Osteosarcoma
    • Multiple myeloma
  • Metastatic lesions: Bone metastasis can occur in any bone, but more commonly occurs in the spine, pelvis, and thigh.
    • Breast cancer
    • Prostate cancer
    • Lung cancer
    • Renal cell carcinoma
    • Thyroid cancer

Pathophysiology

The general principle behind all fractures is that the bone is subjected to a load that overwhelms its bearing capacity, resulting in a loss of structural integrity. 

• With intertrochanteric fractures, blood supply to the femoral head is preserved and the fracture can be surgically repaired.
• With fractures of the femoral neck, the blood supply may be interrupted:
  • May cause AVN of the femoral head
  • Surgical treatment with hemiarthroplasty may be indicated.

Clinical Presentation and Diagnosis

The presentation of a patient with a hip fracture depends on the clinical situation.

History

• Usually presents with groin pain
• Falls in the elderly: Determining the reason for the fall is also important. The following comorbidities should be addressed:
  • Syncope
  • Stroke
  • Vertigo
  • Arrhythmia
  • Seizure
• Mechanism of injury:
  • A fall directly onto the lateral hip
  • A twisting mechanism in which the patient’s foot is planted and the body rotates
  • A sudden, spontaneous completion of a fragility fracture, which then causes a fall (instead of a fall causing a fracture)
  • Some patients may report no trauma at all (5%).
• High-impact trauma:
  • Motor vehicle accidents: Patients may have multiple traumatic injuries.
  • Fall from a great height such as from a roof or tree
  • A fall down the stairs
  • Gunshot injuries

Physical examination

• Tenderness to palpation over the greater trochanter 
• Immobility due to pain/inability to support weight
• Deformity of the lower limb
• Limb length discrepancy
• External rotation of the affected limb
• Ecchymosis over the fracture site
• Altered mental status: Elderly patients may experience delirium.
• The skin may have lacerations, posing a risk for infection.

Diagnosis

The diagnosis of a hip fracture is made clinically and with diagnostic imaging. A hip fracture may be complicated by a dislocation depending on the degree of adduction at the time of impact, especially in motor vehicle accidents.

• X-ray: An anteroposterior (AP) X-ray of the hip is ideal.
  • Fracture description:
    • Location of fracture lines (extra or intracapsular)
    • Complete or incomplete
    • Displacement
  • Secondary findings:
    • Increased opacity of soft tissues (inflammation and edema)
    • Periosteal reaction/callus formation
• CT/MRI:
  • MRI is the gold standard.
  • Best visualization of pelvic and femoral anatomy 
  • CT is the best alternative if MRI is not available.
  • Unstable patients should NOT be taken for a scan.
• Laboratory tests:
  • CBC
  • Serum chemistry panel with renal function (creatinine and BUN)
  • PT and PTT
  • Type and cross for possible transfusion

Management

Definitive management depends on the type of fracture and requires consultation with an orthopedic surgeon.

Treatment

• Goals of treatment:
  • Stable fixation that always allows for immediate weight bearing
  • Maximization of the potential for return to the pre-fracture level of mobility
  • Minimization of the potential for implant failure (if present)
• Initial management:
  • Fluid replacement therapy
  • Blood transfusion, if indicated
  • Analgesia
  • Orthopedic consult
  • NO traction
  • Infection prophylaxis in the case of an open wound
• Nonoperative management:
  • Some debilitated patients may not be surgical candidates:
    • Nonambulatory/bedridden patients with mild pain
    • Unstable patients with major, uncorrectable comorbid disease
  • Patients at the end stage of a terminal illness 
• Orthopedic surgical management:
  • Definitive procedure depends on the fracture type (extracapsular/intracapsular).
  • Open reduction internal fixation is usually performed:
    • Improved outcomes over conservative management
    • May be performed with a regional nerve block
• Oncology consultation:
  • If the fracture is pathological in origin
  • Palliative procedures may be indicated in patients with bone malignancy:
    • Restore mobility 
    • Reduce pain 
• Rehabilitation care:
  • Deep vein thrombosis (DVT) prophylaxis:
    • Compression socks
    • Anticoagulation
  • Postoperative blood transfusion may be needed if Hb < 8 g/dL
  • Early mobilization is highly encouraged.
  • Intensive physical therapy to restore previous mobility

Complications

• Infection
• Nonunion: 1%–30%. Rates are lower with intertrochanteric fractures.
• Chronic pain
• AVN: 
  • Treatment is controversial.
  • May require surgical total hip arthroplasty
• Post-traumatic osteoarthritis
• DVT: 
  • Blood clots can form in the arm or leg veins after a period of immobility and decreased activity. 
  • Anticoagulants are indicated if the patient is at high risk for DVT.
• Fat embolism:
  • Possibly due to the introduction of fat globules into the systemic circulation after a fracture
  • Clinical presentation: 
    • Neurological abnormalities
    • Petechial rash
    • Hypoxia may mimic the presentation of pulmonary embolism.
  • Consequences are similar to those in thrombotic embolism.
  • Treatment is supportive.
• Delirium in the elderly

Prognosis

• 40%–60% of patients regain baseline mobility.
• 20%–60% of previously independent patients become dependent for at least 1 activity.
• Mortality:
  • 10% at 1 month
  • 30% at 1 year

Differential Diagnosis

• Osteoarthritis of the hip: the most common form of arthritis due to cartilage destruction and changes of the subchondral bone. The risk of developing osteoarthritis of the hip increases with age, obesity, repetitive joint use, or trauma.
• Acute hip dislocation: uncoupling of the femoral head from the acetabulum, usually due to trauma. Patients often present after an injury or accident. Diagnosis is made clinically and based on an X-ray. Management is with reduction or surgery.
• Pelvic fracture: a disruption in the cortex of the pelvic bone due to high-energy trauma or osteoporosis. Patients usually present with limb length discrepancy, intense pain on palpation, and mechanical instability. Diagnosis is made clinically and confirmed with diagnostic imaging. Management may be nonsurgical in fragility fractures due to osteoporosis, and surgical in patients who have undergone trauma.
• Osteosarcoma: a primary malignant tumor of the bone characterized by the production of osteoid or immature bone by tumor cells. Osteosarcoma is most common in children and young adults and most frequently affects the growth plates of long bones; however, any bone can be involved. Osteosarcoma can present with pain, swelling, a palpable mass, and, sometimes, a pathologic fracture. Diagnosis is established with imaging studies and biopsy. Treatment involves systemic chemotherapy and surgical resection.