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Updated: Feb 12 2024

Femoral Neck Fractures

Images
https://upload.orthobullets.com/topic/1037/images/Xray - AP - Garden II - emed_moved.jpg
https://upload.orthobullets.com/topic/1037/images/Xray - AP - Garden 1 - emed_moved.jpg
https://upload.orthobullets.com/topic/1037/images/Xray - AP - Garden III - emed_moved.jpg
https://upload.orthobullets.com/topic/1037/images/femoral_neck_fracture_-_valgus_impacted_1a.jpg
  • Summary
    • Femoral neck fractures are common injuries to the proximal femur associated with increased risk of avascular necrosis, and high levels of patient morbidity and mortality.
    • Diagnosis is generally made radiographically with orthogonal radiographs of the hip.
    • Treatment is generally operative with open reduction and internal fixation versus arthroplasty depending on the age of the patient, activity demands and pre-injury mobility. 
  • Epidemiology
    • Incidence
      • common
        • increasingly common due to aging population
    • Demographics
      • women > men
      • Caucasians > African Americans
      • United states has highest incidence of hip fx rates worldwide
  • Etiology
    • Pathophysiology
      • healing potential
        • femoral neck is intracapsular, bathed in synovial fluid
        • lacks periosteal layer
        • callus formation limited, which affects healing
    • Mechanism
      • high energy in young patients
      • low energy falls in older patients
    • Associated injuries
      • femoral shaft fractures
        • 6-9% associated with femoral neck fractures
        • treat femoral neck first followed by shaft
  • 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)
  • Classification
      • Garden Classification
      • (based on AP radiographs and does not consider lateral or sagittal plane alignment)
      • Type I
      • Incomplete fx (valgus impacted)
      • Type II
      • Complete fx, nondisplaced
      • Type III
      • Complete fx, partially displaced
      • Type IV
      • Complete fx, fully displaced
      • 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/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
        • AP
          • traction-internal rotation AP hip is best for defining fracture type
        • cross-table lateral
        • full-length femur
      • optional views
        • consider obtaining dedicated imaging of uninjured hip to use as template intraop
    • CT
      • indications
        • helpful in determining displacement and degree of comminution in some patients
    • MRI
      • indications
        • helpful to rule out occult fracture
        • not helpful in reliably assessing viability of femoral head after fracture
    • Bone scan
      • indications
        • helpful to rule out occult fracture
        • not helpful in reliably assessing viability of femoral head after fracture
    • Duplex Scanning
      • indications
        • 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
      • closed reduction with cannulated screw fixation
        • indications
          • nondisplaced transcervical fx
          • Garden I or II in the physiologically elderly
          • displaced transcervical fx in young patient
            • achieve reduction to limit vascular insult
            • reduction must be anatomic, so open if necessary
      • open reduction internal fixation (ORIF)
        • indications
          • displaced fractures in young or physiologically young patients
            • ORIF indicated for most pts <50 years of age
              • female sex associated with increased reoperation rate 
        • techniques
          • sliding hip screw
            • indications
              • basicervical fracture
              • vertical fracture pattern in a young patient
                • sliding hip screw biomechanically superior to cannulated screws (may not be clinically superior)
            • consider placement of additional cannulated screw above sliding hip screw to prevent rotation
        • indications
          • controversial
          • debilitated elderly patients
          • metabolic bone disease
        • techniques
          • cemented hemiarthroplasty
            • decreased intraoperative and postoperative fracture rates in elderly insufficiency fractures
            • improved short and medium term mobility 
        • indications
          • controversial
          • older active patients
          • patients with preexisting hip osteoarthritis
            • more predictable pain relief and better functional outcome than hemiarthroplasty
          • Garden III or IV in patient < 85 years
  • Techniques
    • General Technical Principles
      • 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 (preferably <24-48 hours)
          • the benefits of early mobilization cannot be overemphasized
            • improved outcomes in medically fit patients if surgically treated less than 4 days from injury
          • preoperative echocardiograms have been shown to delay the time to surgery without any effect on treatment decisions
      • anesthesia type
        • spinal versus general
          • no difference in postoperative delirium, mortality or ambulatory function at 60 days 
      • treatment approach based on
        • degree of displacement
        • physiologic age of the patient (young is < than 50 years old)
        • ipsilateral femoral neck and shaft fractures
    • Closed reduction with 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
    • Open reduction internal fixation (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 
        • 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
        • technique
          • 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
      • fixation
        • 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
    • Hemiarthroplasty
      • approach
        • posterior approach has increased risk of dislocations
        • anterolateral approach has increased abductor weakness
      • technique
        • cemented superior to uncemented in elderly population (decreased revision rates)
        • 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 and internal fixation
      • complications
        • higher rate of dislocation with THA (~ 10%)
          • about five times higher than hemiarthroplasty
  • Complications
    • Osteonecrosis
      • recent studies fail to demonstrate an association between time to fracture reduction and subsequent AVN
      • increased risk with
        • increase initial displacement
          • AVN can still develop in nondisplaced injuries
        • nonanatomical reduction
        • sliding hip screw
          • reported by the FAITH study
      • 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
        • free vascularized fibula graft (FVFG)
          • indicated in young patients with a viable 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
      • 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% failure with fixation techniques
          • 8% failure 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
      • sliding hip screw with lower reoperation rates compared to cannulated screws
        • displaced femoral neck fractures
        • basicervical femoral neck fractures
        • current smokers
    • Reducing complications with co-management service
      • orthopaedic geriatric co-management of trauma patients has been demonstrated to yield
        • decreased mortality, post-operative complications, time to surgery, length of stay (though conflicting results on length of stay)
        • improved post-operative mobility at 4 months
      • important to mitigate risks of hospital delirium which may lead to increased length of stay
    • Loss of independence
      • requiring walking aids and assisted living following fracture surgery
        • the timed up and go (TUG) test has been identified as a reliable predictor of a patient's need for post-operative assistive devices
          • Normal TUG is <12 seconds in all age groups
          • Persistent use of ambulatory aids is predicted if TUG > 26 seconds
      • associated factors
        • age >80 years
        • ASA class >1
        • prior walking aid use
        • current tobacco use
        • implant placement quality
        • nondisplaced fracture
        • not requiring revision surgery
  • Prognosis
    • Most expensive fracture to treat on per-person basis
    • 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%
      • mortality risk is decreased at 30 days and at 1 year post-op when surgical intervention is performed within 24 hours of admission
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