Hip Fractures: Intracapsular Neck of Femur Fractures

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Definition of an intracapsular neck of femur fracture (#NOF)

• Intracapsular neck of femur fractures (#NOF)  occur within the capsule of the hip joint
• The blood supply to femoral head travels in a retrograde direction via the capsule. As such, any fracture within the capsule could be likely to damage this blood supply (see below, complications)

 

Epidemiology of intracapsular neck of femur fractures

• The classic patient is an elderly female with a low body mass index
  • This is an example of an insufficiency fracture and therefore most likely to occur in those with other comorbidities
• In young patients this is more often the result of high energy trauma such as road traffic accidents or falls from a height.
  • As such ATLS principles and investigation for coexisting injury must occur in these patients

 

 

Risk factors for neck of femur fractures

• The commonest cause in the elderly is generally a fall onto the side of the fracture
• The primary risk factors is osteoporosis but also other age-related issues which might make a frail patient likely to fall (i.e. poor vision, poor proprioception, arthritis, dementia)

 

Presentation of neck of femur fractures

• Fall followed by pain in the groin with referred pain to the thigh
• Limited ability to weight bear
• Limited range of movement (particularly straight leg raise)
• External rotation with shortening of the limb length in displaced fractures

 

 

Differential diagnosis of intracapsular neck of femur fractures

• Extracapsular neck of femur fractures
• Severe osteoarthritis of the hip/fracture osteophytes
• Femoral shaft fractures
• Acetabular/pelvic fractures (including pubic symphysis fractures)
• Septic arthritis of the hip
• Radicular pain from spinal pathology
• Psoas abscess

 

Classification of intracapsular neck of femur fractures

• The most common classification is the Garden classification:
  • Garden I: incomplete and undisplaced fracture
  • Garden II: Complete but undisplaced fracture
  • Garden III: Complete fracture with partial displacement
  • Garden IV: Complete fracture with 100% displacement

 

 

Initial management of intracapsular neck of femur fractures

• ABC approach
  • Bloods, including clotting and G&S
  • Fluids +/- RBC if shocked (a lot of blood can be lost into the hip following fracture)
• AP and lateral radiographs of the pelvis and affected hip
  • Full length femur radiographs should be obtained if there is any suspicion of a pathological fracture (such as malignancy)
• Once fracture determined
  • Po analgesia +/- a fascia iliaca block
  • Discuss with the orthopaedic on call team

 

Further management of intracapsular neck of femur fractures

• This depends on the performance status of the patient as well as the displacement of the fracture
• Non-displaced fractures (Garden I+II)
  • Relatively young patients (either chronologically or more important, physiologically) should have urgent internal fixation via 3 or 4 parallel partially threaded cancellous screws
• Displaced fractures (Garden III+IV), or even non-displaced fractures in the context of patients unlikely to tolerate non-weight bearing
  • Replacement of the femoral head to obviate the risks of avascular necrosis (see below)
  • This is most often via a hemiarthroplasty
    • Younger, fitter patients are being offer a primary total hip replacement (THR) in centres able to provide the service

 

Complications following intracapsular neck of femur fractures

• General risks
  • Anaesthetic risks
  • Blood loss in theatre
  • Venous thromboembolic disease
    • Give anticoagulation +/- thromboembolic prevention stockings as per local protocol
• Internal fixation
  • Avascular necrosis
  • Mal-union or non-union of the fracture
  • Infection of metalwork

·        Hemiarthroplasty

• Dislocation of prosthesis
• Peri-prosthetic fractures
• Metalwork  failure or acetabular erosion and consequent need for revision

 

Prognosis of intracapsular neck of femur fractures

• The presence of a hip fracture increase mortality for the first year
• After this period and levels return back to near normal

 

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