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Introduction
  • Epidemiology
    • increasingly common due to aging population
    • women > men
    • whites > blacks
    • United states has highest incidence of hip fx rates worldwide
    • most expensive fracture to treat on per-person basis
  • Mechanism
    • high energy in young patients
    • low energy falls in older patients
  • Pathophysiology
    • healing potential
      • femoral neck is intracapsular, bathed in synovial fluid
      • lacks periosteal layer
      • callus formation limited, which affects healing
  • Associated injuries
    • femoral shaft fractures
      • 6-9% associated with femoral neck fractures  
      • treat femoral neck first followed by shaft
  • Prognosis
    • mortality
      • ~25-30% at one year (higher than vertebral compression fractures)  
    • predictors of mortality
      • pre-injury mobility is the most significant determinant for post-operative survival 
      • in patients with chronic renal failure, rates of mortality at 2 years postoperatively, are close to 45%   

 

Anatomy
  • Osteology
    • normal neck shaft-angle 130 +/- 7 degrees
    • normal anteversion 10 +/- 7 degrees
  • Blood supply to femoral head  
    • major contributor is medial femoral circumflex (lateral epiphyseal artery)
    • some contribution to anterior and inferior head from lateral femoral circumflex
    • some contribution from inferior gluteal artery
    • small and insignificant supply from artery of ligamentum teres
    • displacement of femoral neck fracture will disrupt the blood supply and cause an intracapsular hematoma (effect is controversial) q q
Classification
 
Garden Classification
(based on AP radiographs and does not consider lateral or sagittal plane alignment)

Type I Incomplete, ie. valgus impacted  
Type II Complete fx. nondisplaced  
Type III Complete, partially displaced  
Type IV Complete, fully displaced  
Posterior roll-off and/or angulation of femoral head leads to increased reoperation rates
 
Simplified Garden Classification
Nondisplaced Includes Garden I and II
Displaced Includes Garden IIII and IV
 
Pauwels Classification
 
(based on vertical orientation of fracture line)

Type I < 30 deg from horizontal

Type II 30 to 50 deg from horizontal

Type III > 50 deg from horizontal (most unstable with highest risk of nonunion and AVN)

 
Presentation
  • Symptoms
    • impacted and stress fractures
      • slight pain in the groin or pain referred along the medial side of the thigh and knee
    • displaced fractures
      • pain in the entire hip region
  • Physical exam
    • impacted and stress fractures
      • no obvious clinical deformity
      • minor discomfort with active or passive hip range of motion, muscle spasms at extremes of motion
      • pain with percussion over greater trochanter
    • displaced fractures
      • leg in external rotation and abduction, with shortening
Imaging
  • Radiographs
    • recommended views
      • obtain AP pelvis and cross-table lateral, and full length femur film of ipsilateral side
      • consider obtaining dedicated imaging of uninjured hip to use as template intraop
      • traction-internal rotation AP hip is best for defining fracture type q
      • Garden classification is based on AP pelvis
  • CT
    • helpful in determining displacement and degree of comminution in some patients
  • MRI 
    • helpful to rule out occult fracture q
    • not helpful in reliably assessing viability of femoral head after fracture
  • Bone scan
    • helpful to rule out occult fracture
    • not helpful in reliably assessing viability of femoral head after fracture
  • Duplex Scanning
    • indication
      • rule out DVT if delayed presentation to hospital after hip fracture 
Treatment
  • Nonoperative
    • observation alone
      • indications
        • may be considered in some patients who are non-ambulators, have minimal pain, and who are at high risk for surgical intervention
  • Operative
    • ORIF
      • indications
        • displaced fractures in young or physiologically young patients
          • ORIF indicated for most pts <65 years of age
    • cannulated screw fixation 
      • indications
        • nondisplaced transcervical fx
        • Garden I and II fracture patterns in the physiologically elderly
        • displaced transcervical fx in young patient
          • considered a surgical emergency
          • achieve reduction to limit vascular insult
          • reduction must be anatomic, so open if necessary
    • sliding hip screw   
      • indications
        • basicervical fracture
        • vertical fracture pattern in a young patient
          • biomechanically superior to cannulated screws
      • consider placement of additional cannulated screw above sliding hip screw to prevent rotation
    • hemiarthroplasty   
      • indications
        • controversial
        • debilitated elderly patients
        • metabolic bone disease
    • total hip arthoplasty q q    
      • indications
        • controversial
        • older active patients
        • patients with preexisting hip osteoarthritis
          • more predictable pain relief and better functional outcome than hemiarthroplasty
        • arthroplasty for Garden III and IV in patient < 85 years
Techniques
  • General Surgical Consideration
    • time to surgery
      • controversial
        • reduction method and quality has more pronounced effect on healing than surgical timing
      • elderly patients with hip fractures should be brought to surgery as soon as medically optimal 
        • the benefits of early mobilization cannot be overemphasized
          • improved outcomes in medically fit patients if surgically treated less than 4 days from injury 
    • treatment approach based on
      • degree of displacement
      • physiologic age of the patient (young is < than 50
      • ipsilateral femoral neck and shaft fractures 
        • priority goes to fixing femoral neck because anatomic reduction is necessary to avoid complications of AVN and nonunion
    • fixation with implants that allow sliding
      • permit dynamic compression at fx site during axial loading
      • can cause shortening of femoral neck
        • prominent implants
        • affects biomechanics of hip joint
        • lower physical function on SF-36
        • decreased quality of life
      • anatomic reduction with intraop compression and placement of length stable devices decrease shortening
    • open versus closed reduction 
      • worse outcomes with displacement > 5 mm (higher rate of osteonecrosis and nonunions)
      • no consensus on which reduction approach is superior
      • multiple closed reduction attempts are associated with higher risk of osteonecrosis of the femoral head
  • ORIF
    • approach
      • limited anterior Smith-Peterson 
        • 10cm skin incision made beginning just distal to AIIS
        • incise deep fascia
        • develop interval between sartorious and TFL
        • external rotation of thigh accentuates dissection plane
        • LFCN is identified and retracted medially with sartorius
        • identify tendinous portion of rectus femoris, elevate off hip capsule
        • open capsule to identify femoral neck
      • Watson-Jones
        • used to gain improved exposure of lower femoral neck fractures
        • skin incision approx 2cm posterior and distal to ASIS, down toward tip of greater trochanter
        • incision curved distally and extended 10cm along anterior portion of femur
        • incise deep fascia
        • develop interval between TFL and gluteus medius
        • anterior aspect of gluteus medius and minimus is retracted posteriorly to visualize anterior hip capsule
        • capsule sharply incised with Z-shape incision
        • capsulotomy must remain anterior to lesser trochanter at all times to avoid injury to medial femoral circumflex artery
      • reduction (method may vary)
        • evacuate hematoma
        • place A to P k-wires into femoral neck/head proximal to fracture to use as joysticks for reduction
        • insert starting k-wire (for either cannulated screw or sliding hip screw) into appropriate position laterally, up to but not across the fracture
        • once reduction obtained, drive starting k-wire across fracture
        • insert second threaded tipped k-wire if adding additional fixation
  • Cannulated Screw Fixation
    • technique
      • three screws if noncomminuted (3 screw inverted triangle shown to be superior to two screws)
      • order of screw placement (this varies)
        • 1-inferior screw along calcar
        • 2-posterior/superior screw
        • 3-anterior/superior screw
      • obtain as much screw spread as possible in femoral neck
      • inverted triangle along the calcar (not central in the neck) has stronger fixation and higher load to failure 
      • four screws considered for posterior comminution
        • clear advantage of additional screws not proven in literature
      • starting point at or above level of lesser trochanter to avoid fracture
      • avoid multiple cortical perforations during guide pin or screw placement to avoid development of lateral stress riser
  • Hemiarthroplasty
    • approach
      • posterior approach has increased risk of dislocations
      • anterolateral approach has increased abductor weakness
    • technique
      • cemented superior to uncemented
      • unipolar vs. bipolar
  • Total Hip Replacement
    • technique
      • should consider using the anterolateral approach and selective use of larger heads in the setting of a femoral neck fracture
    • advantages
      • improved functional hip scores and lower re-operation rates compared to hemiarthroplasty 
    • complications
      • higher rate of dislocation with THA (~ 10%)
        • about five times higher than hemiarthroplasty 
 
Complications
  • Osteonecrosis 
    • incidence of 10-45% q q
    • recent studies fail to demonstrate association between time to fracture reduction and subsequent AVN
    • increased risk with
      • increase initial displacement
        • AVN can still develop in nondisplaced injuries
      • nonanatomical reduction
    • treatment
      • major symptoms not always present when AVN develops
      • young patient
        • > 50% involvement then treat with FVFG vs THA
      • older patient
        • prosthetic replacement (hemiarthroplasty vs THA)
  • Nonunion
    • incidence of 5 to 30%
      • increased incidence in displaced fractures
      • no correlation between age, gender, and rate of nonunion
    • varus malreduction most closely correlates with failure of fixation after reduction and cannulated screw fixation. 
    • treatment
      • valgus intertrochanteric osteotomy   
        • indicated in patients after femoral neck nonunion
          • can be done even in presence of AVN, as long as not severely collapsed
          • turns vertical fx line into horizontal fx line and decreases shear forces across fx line q
      • free vascularized fibula graft (FVFG)
        • indicated in young patients with a nonviable femoral head 
      • arthroplasty  
        • indicated in older patients or when the femoral head is not viable
        • also an option in younger patient with a nonviable femoral head as opposed to FVFG
      • revision ORIF
  • Dislocation
    • higher rate of dislocation with THA (~ 10%)
      • about seven times higher than hemiarthroplasty
  • Failure rates q
    • high early failure rates in fixation group, which stabilizes after 2 years
      • 2-year follow-up (elderly population >70 years) with displaced femoral neck fractures
        • 46% with fixation techniques
        • 8% with arthroplasty techniques
      • 2-to-10 year follow-up
        • failure rate approx. 2-4%, respectively
    • overall failure rates still higher in fixation vs. arthoplasty at 10-year follow-up
 

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