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Hip Fractures in Adults

Anatomy

Unstable 4 part Pertrochanteric NOF
Unstable 4 part Pertrochanteric NOF

Bony

Normal

  • neck shaft angle
    • 130° ± 7°
  • femoral anteversion
    • 10° ± 7°
  • Femoral head diameter
    • 40 to 60mm
  • cartilage thickness
    • 4mm
    • tapering to 3mm on the periphery.

Vascular

The arterial supply to the femoral head

  • three sources
    1. Endosteal arteries
    2. round ligament
      • (ligamentum teres, a branch of the obturator or medial circumflex artery). 
      • This is significant in only around 1/3. 
      • also known as the medial epiphyseal vessels.
    3. extracapsular vessels.
      • arise predominantly from the medial circumflex femoral artery, a branch of the profunda femoris
        • lies just underneath the proximal margin of the quadratus femoris.
      • A lesser contribution comes from the lateral circumflex femoral artery
  • Extracapsular Arterial Ring
    • These two arteries ( MCFA & LCFA) give rise to an extracapsular arterial ring
      • located at the base of the femoral neck. 
    • ascending cervical arteries arise from this ring
      • also known as the retinacular arteries of Weitbrecht
      • run upward beneath the capsule
      • then underneath synovial reflections. 
      • most important branch is the lateral branch, known as the lateral epiphyseal artery.
    • At the margin of the articular cartilage
      • ascending cervical arteries form a subsynovial intraarticular arterial ring (so named by Chung). 
      • Epiphyseal branches arise from the ring that penetrate the head.

Epidemiology

  • incidence doubles with every decade over 50.
  • F:M 2-3:1

Risk factors

  1. Whites>blacks
  2. Urban dwellers
  3. Smokers
  4. Excessive alcohol or caffeine intake
  5. Physical inactivity
  6. Previous hip fracture
  7. Significant weight loss in midlife
  8. Use of psychotropic medication
  9. Senile dementia
  10. Postmenarche
  11. Institutionalization
  12. Osteoporosis
  13. Inadequate dietary calcium intake

Aetiology

  • High violence injury in young patients
  • Low violence injury in older patients (over 50).
  • Hip protectors may be protective, particularly in nursing home patients.

Classification

  • Extracapsular vs. intracapsular.

Investigations

  • MRI
    • more cost effective than bone scanning in detecting occult femoral neck fractures.

Prevention of thromboembolic disease

  • There is at least a 40% rate of TED in hip fracture patients without prophylaxis.
  • Subcutaneous LMWH has been shown to be an effective prophylaxis in patients with hip fracture.
  • Subcutaneous heparin has not been shown to be effective.
  • Lancet trial showed low dose aspirin was superior to placebo in preventing fatal PEs in hip fracture patients.

Functional recovery

  • 40-60% of elderly patients with hip fractures are able to return home immediately after hospitalization.
  • 10-20% become nonambulatory in the first year after fracture.

Mortality

  • 1 year mortality rate
    • 14 to 36%
    • higher than in age matched controls. 
  • majority of deaths occurs in the first 4-6 months
  • Once the patients get to 1 year their mortality parallels their peers without fractures. 
  • 50% of patients with femoral neck fractures survive 5 years.
  • lowest mortality rates are in community dwellers without dementia. 
  • Institutionalized patients with severe dementia have in hospital mortality rates of up to 50%.
  • A surgical delay of more than 3 days approximately doubled the risk of death before the end of the first postoperative year. 
  • Delay is only acceptable to stabilize medical conditions.
  • Use of spinal vs. general anaesthesia doesn’t appear to affect mortality.
  • mortality rate is slightly higher in patients treated with THR than with internal fixation in the first month, but by 3-4 months mortality is equivalent.

 

Webpage Last Modified: 28 January, 2010