Pathogenesis

  • 90% of hip fractures in elderly are caused by fall from standing
  • A fall from standing position effects enough force to fracture a hip
  • Normally, such a fall doesn’t result in fracture because the faller will catch himself
  • Hip fractures from falling indicate intrinsic bone pathology or a condition predisposing to fall
  • Some clinicians are not sure whether porous bone is the problem per se or is it just an indicator of the "Dwindles theory"
  • Dwindles theory : osteoporosis can be part of diminishing body abilities, as well as comorbidities, that make falling more likely or protecting oneself during a fall less likely

Aetiology

  • Insufficient bone maintenance
    • Osteoporosis
    • Hyperparathyroidism
    • Metastasis
    • Paget’s disease
  • Increased falling
    • Peripheral neuropathy, causing frequent tripping
    • Vasculopathy; e.g. CVA or TIA causing sudden LOC
    • Neurodegenerative dementia causing ataxia, vision degeneration
  • Poor self-protection during fall : slowed reflexes secondary to aging

Associations

  • Increased frequency with
    • Age
    • Dementia
    • Malignancy
    • Chronic illness
  • Decreased frequency with
    • Long term physical activity
    • Supplemental Vitamin D and calcium
    • HRT

Nutritional factors

  • Vitamin D and Ca supplementation helps to prevent bone loss
  • Vitamin D has not shown to be helpful in hip fracture not secondary to osteoporosis

Prevention

  • External hip protectors (pillows) reduce hip fractures in the elderly by 50%
  • Prescribe non-sedative alternatives for medical conditions in elderly
  • Use the lowest effective dose of sedative medications, when necessary

Natural History

  • 310,000 adults hospitalized with hip fractures in U.S in 2003
  • Lifetime risk
    • Women 17.5%
    • Men 6%
  • Average age for first femoral neck fracture
    • Women 77 years
    • Men 72 years
  • High risk women
    • Post-menopausal
    • Low BMI
    • Android body habitus (less adipose at hip)
  • 15-24% 1-year mortality

Clinical Presentation

  • Painful, swollen hip with a history of fall
  • Reduced range of motion of hip joint
  • Missed/ late cases may present with complications

Differential Diagnosis

  • Hip fractures
    • Acetabulum
    • Femur head
    • Femur neck
  • Hip osteoarthritis
  • Osteonecrosis
  • Trochanteric bursitis
  • Meralgia paresthetica
  • AV occlusive disease

Psychosocial impact of disease

  • Decreased mobility may lead to feeling of vulnerability / loss of sense of self-efficacy
  • Family may label the patients too frail to care for  themselves and send them to nursing homes
  • The patient may become more susceptible to dementia and depression

Imaging and Diagnostic Studies

X-Ray

  • On AP view, with femur maximally internally rotated, the usual S and reverse S formed by the femoral neck and head may be disrupted in a displaced neck fracture
  • On lateral view, if the angle between medial femoral shaft and trabecular lines going from shaft to head is <160° or >170° neck fracture is suggested
  • Hip may appear normal on X-Ray in
    • Non-displaced neck fracture
    • Stress fracture
    • Incomplete fracture

MRI

  • 100% specificity
  • Indicated in
    • Suspicious cases with normal X-Ray
    • Investigating the underlying process; e.g. metastasis

Laboratory evidence

  • Not diagnostic of fracture, but may give clue about fracture aetiology
  • For example, CBC may provide clue to a primary cancer; e.g. myeloma, leukemia or lymphoma

Treatment

Non-operative management

  • Selected only in rare (< 5%) patients, not up to the challenge of surgery
  • Bed rest and pain medications are recommended

Surgery

  • Open reduction and internal fixation
  • Joint replacement

Outcome

  • 1/3 recover
  • 1/3 lose a level of function
  • 1/3 die within 1 year

Complications

  • Typical complications of surgery
    • Infection
    • Hemorrhage
    • Anesthesia-related mortality/morbidity
  • AVN of femoral head
    • Seen in 10-40% of cases
    • Risk increases to 53% if Garden’s alignment index is 155-180 degrees
  • Complications of long period of bed rest
    • Atelectasis
    • DVT
    • PE
    • CVA
  • Non-union : more common in vertical than transverse neck fractures
  • Parker’s meta-analysis found
    • Internal fixation causes less operative trauma to the hip
    • Arthroplasty results in fewer revisions and lower risk of AVN and non-union