Hip Fracture

Description

• Intracapsular
  • Femoral neck, subcapital, or transcervical
  • Intracapsular femoral neck fractures may disrupt blood supply, resulting in avascular necrosis (1).
• Extracapsular
  • Intertrochanteric: fracture between the neck of the femur and the lesser trochanter
  • Subtrochanteric: fracture below the lesser trochanter
• 90% caused by a low-impact fall or twist on planted foot (2)
• System(s) affected: musculoskeletal, neurologic, vascular
• Synonym(s): subcapital fracture; trochanteric fracture; femoral neck fracture

Epidemiology

• Predominant age: 80% occur in patients ≥60 years.
• Average age: 80 years
• 80% of all hip fractures are in women.
• Hip fractures in men are associated with greater mortality (up to 38% in the 1st year) (3).

Incidence

• In the United States, 320,000 elderly patients sustain hip fractures annually—this is expected to increase as the population ages (4).
• In the United States, women >75 years; 1% annual incidence
• 4.5 million people worldwide are disabled from hip fractures each year with an estimated 21 million people in the next 40 years (5).

Prevalence
Lifetime prevalence: 20% for women; 10% for men (1)

Etiology and Pathophysiology

Increased bone resorption increases risk of osteoporosis and hip fracture.

• Osteoporosis
• Direct blunt trauma
• Pathologic conditions (e.g., bone cancer)
• Stress fracture caused by overtraining
• Avascular necrosis

Genetics
No known genetic factor

Risk Factors

• Age >65 years
• Female sex
• Low socioeconomic status
• History of previous fracture (>50 years) or history of a low-impact fracture
• Family history of osteoporosis
• Gait, sensory, or visual impairment
• Low body mass or deconditioning
• Sedentary lifestyle (on feet <4 hours a day)
• Environmental hazards, such as throw rugs, loose cords, or inadequate lighting in the home
• Foot deformity
• Cigarette smoking
• ≥3 alcoholic beverages a day
• Osteoporosis: low bone mineral density (BMD)
• Osteoarthritis or rheumatoid arthritis
• Hyperthyroidism or diabetes mellitus
• Metastatic bone cancer
• Severe renal disease with secondary hyperparathyroidism
• Polypharmacy (use of ≥4 chronic medications)
• Glucocorticoid use
• Psychoactive medications (SSRIs, benzodiazepines, anticonvulsants)
• Long-term proton pump inhibitor therapy (high doses)
• High-dose levothyroxine
• Antihypertensives: The first 45 days after initiating treatment in the elderly have the highest risk of orthostatic syncope/fall.

General Prevention

Minimize risk factors:

• Address disordered eating or overtraining if concern for female athlete triad.
• Fall prevention
  • Avoid long-acting sedatives and hypnotics in the elderly.
  • Use ambulatory aids (canes or walkers) if patient has unsteady gait.
  • Use sturdy rails in bathrooms, stairs, or ramps; avoid throw rugs and slippery surfaces; ensure adequate lighting. Home safety assessment can reduce falls by 39% (6)[A].
  • Exercise with balance training or tai chi reduces the risk for falls (6)[A].
  • Annual vision exams for elderly
  • Minimize polypharmacy.
• Prophylactic treatment for osteoporosis (3,4)[C]:
  • Magnesium supplementation improves calcium metabolism.
  • Vitamin D supplementation: 800 to 4,000 IU/day PO decreases hip fracture risk (6)[A].
• Ultrasound (US) and/or BMD measurements quantitatively assess bone health; at age 65 years (age 60 years if risk factors)
• Treatment of osteoporosis
  • Treatment with bisphosphonates is successful only if combined with weight-bearing exercise and vitamin D supplementation.
  • Bisphosphonates (adverse effect, esophagitis)
  • Alendronate (Fosamax): 35 (prevention) to 70 mg (management) PO weekly
  • Risedronate (Actonel): 150 mg PO monthly
  • Ibandronate (Boniva): 150 mg PO monthly
  • Zoledronic acid (Reclast): 5 mg IV yearly
  • Estrogen replacement prevents decrease of BMD but has other risks (i.e., increased venous thromboembolism [VTE] and cancer risks).
  • Selective estrogen-receptor modulators decrease risk of vertebral fractures but increases VTE risk.
  • Parathyroid hormone (teriparatide [Forteo]) decreases the risk of vertebral fractures; treatment is limited by long-term safety concerns to 2 years.
  • RANKL inhibitor: denosumab (Prolia) 60 mg SC every 6 months

Commonly Associated Conditions

• Osteoporosis
• Metastatic malignancy
• Impaired cognition
• Gait instability
• Female athlete triad—low caloric intake, menstrual dysfunction, decreased BMD (stress fractures)