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
- 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
- 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
