Femoral Neck Fractures
Brian Boyer, MD
Anatomy
• Physeal closure age 16• Neck-shaft angle
130° ± 7°• Anteversion
10° ± 7°• Calcar Femorale
Posteromedial
dense plate of bone
Blood Supply• Lateral epiphysel artery
– terminal branch MFC artery– predominant blood supply to
weight bearing dome of head
• Artery of ligamentum teres– from obturator artery– supplies anteroinferior head
• Lateral femoral circumflex a.– less contribution than MFC
Blood Supply
fracture displacement=vascular disruption
• revascularization of the head– intact vessels– vascular ingrowth across fracture site
• importance of quality of reduction
– metaphyseal vessels
Epidemiology
• 250,000 Hip fractures annually– Expected to double by 2050
• At risk populations– Elderly: poor balance&vision, osteoporosis, inactivity,
medications, malnutrition• incidence doubles with each decade beyond age 50
– higher in white population
– Other factors: smokers, small body size, excessive caffeine & ETOH
– Young: high energy trauma
Classification
• Pauwels [1935]
– Angle describes vertical shear vector
Classification
• Garden [1961]
I Valgus impacted or
incomplete
II Complete
Non-displaced
III Complete
Partial displacement
IV Complete
Full displacement
** Portends risk of AVN and Nonunion
I II
III IV
Classification
• Functional Classification – Stable
• Impacted (Garden I)
• Non-displaced (Garden II)
– Unstable• Displaced (Garden III and IV)
Treatment
• Goals– Improve outcome over natural history– Minimize risks and avoid complications– Return to pre-injury level of function– Provide cost-effective treatment
Treatment
• Options– Non-operative
• very limited role
• Activity modification
• Skeletal traction
– Operative• ORIF
• Hemiarthroplasty
• Total Hip Replacement
TreatmentDecision Making Variables
• Patient Characteristics– Young (arbitrary physiologic age < 65)
• High energy injuries– Often multi-trauma
• High Pauwels Angle (vertical shear pattern)
– Elderly• Lower energy injury• Comorbidities• Pre-existing hip disease
• Fracture Characteristics– Stable– Unstable
TreatmentYoung Patients(Arbitrary physiologic age < 65)
– Non-displaced fractures• At risk for secondary displacement
• Urgent ORIF recommended
– Displaced fractures• Patients native femoral head best
• AVN related to duration and degree of displacement
• Irreversible cell death after 6-12 hours
• Emergent ORIF recommended
TreatmentElderly Patients
• Operative vs. Non-operative– Displaced fractures
• Unacceptable rates of mortality, morbidity, and poor outcome with non-operative treatment [Koval 1994]
– Non-displaced fractures • Unpredictable risk of secondary displacement
– AVN rate 2X
– Standard of care is operative for all femoral neck fractures
• Non-operative tx may have developing role in select patients with impacted/ non-displaced fractures [Raaymakers 2001]
TreatmentPre-operative Considerations
• Skin Traction not beneficial– No effect on fracture reduction– No difference in analgesic use– Pressure sore/ skin problems– Increased cost– Traction position decreases capsular volume
• Potential detrimental effect on blood flow
TreatmentPre-operative Considerations
• Regional vs. General Anesthesia– Mortality / long term outcome
• No Difference
– Regional • Lower DVT, PE, pneumonia, resp depression, and
transfusion rates
– Further investigation required for definitive answer
TreatmentPre-operative Considerations
• Surgical Timing– Surgical delay for medical clearance in
relatively healthy patients probably not warranted
• Increased mortality, complications, length of stay
– Surgical delay up to 72 hours for medical stabilization warranted in unhealthy patients
ORIF
Hemi
THR
Non-displaced Fractures
• ORIF standard of care• Predictable healing
– Nonunion < 5%
• Minimal complications– AVN < 8%
– Infection < 5%
• Relatively quick procedure– Minimal blood loss
• Early mobilization– Unrestricted weight bearing with assistive device PRN
ORIF
• Ideal reduction is Anatomic– Acceptable: < 15º valgus < 10º AP angulation * may need to open in order achieve reduction
• Fixation: Multiple screws in parallel – No advantage to > 3 screws– Uniform compression across fracture– In-situ pin impacted fractures * ↑ AVN with disimpaction [Crawford 1960]
– Fixation most dependent on bone density
ORIF• Screw location
– Avoid posterior/ superior quadrant» Blood supply
» Cut-out
– Biomechanical advantage to inferior/ calcar screw
[Booth 1998]
ORIF• Compression Hip Screws
– Sacrifices large amount of bone
– May injure blood supply
– Biomechanically superior in cadavers
– Anti-rotation screw often needed
– Increased cost and operative time
• No clinical advantage over parallel screws * May have role in high energy/ vertical shear
fractures
ORIFIntracapsular Hematoma
• incidence- 75% have some – no difference displaced/nondisplaced
• ? Amount of > 100 mm in 25%• sensitive to leg position
– extension + internal rotation= bad
• animal models: pressure= perfusion• Theoretical benefit with NO clinical proof
– but it doesn’t hurt
Displaced FracturesHemiarthroplasty vs. ORIF
• ORIF is an option in elderly** Surgical emergency in young patients **
• Complications• Nonunion 10 -33%
• AVN 15 – 33%• AVN related to displacement
• Early ORIF no benefit
• Loss of reduction / fixation failure 16%
Displaced FracturesHemiarthroplasty vs. ORIF
• Hemi associated with• Lower reoperation rate (6-18% vs. 20-36%)• Improved functional scores• Less pain• More cost-effective• Slightly increased short term mortality
• Literature supports hemiarthroplasty for displaced fractures [Lu-yao JBJS 1994]
[Iorio CORR 2001]
HemiarthroplastyUnipolar vs. Bipolar
• Bipolar theoretical advantages• Lower dislocation rate• Less acetabular wear/ protrusio• Less Pain• More motion
HemiarthroplastyUnipolar vs. Bipolar
• Bipolar– Disadvantages
• Cost
• Dislocation often requires open reduction
• Loss of motion interface (effectively unipolar)
• Polyethylene wear/ osteolysis not yet studied for Bipolars
HemiarthroplastyUnipolar vs. Bipolar
– Complications / Mortality / Length of stay• No Difference
– Hip Scores / Functional Outcomes• No significant difference• Bipolar slightly better walking speeds, motion, pain
– Revision rates• Unipolar 20% vs. Bipolar 10% (7 years)
– Unipolar more cost-effective
• Literature supports use of either implant
HemiarthroplastyCemented vs. Non-cemented
• Cement (PMMA)– Improved mobility, function, walking aids
– Most studies show no difference in morbidity / mortality
• Sudden Intra-op cardiac death risk slightly increased: – 1% cemented hemi for fx vs. 0.015% for elective arthroplasty
• Non-cemented (Press-fit)– Pain / Loosening higher
– Intra-op fracture (theoretical)
HemiarthroplastyCemented vs. Non-cemented
• Conclusion:– Cement gives better results
• Function
• Mobility
• Implant Stability
• Pain
• Cost-effective
– Low risk of sudden cardiac death
• Use cement with caution
TreatmentPre-operative Considerations
• Surgical Approach– Posterior approach to hip
• 60% higher short-term mortality vs. anterior
– Dislocation rate• No significant difference [Lu-Yao JBJS 1994]
Total Hip Replacement
• Dislocation rates:– Hemi 2-3% vs. THR 11% (short term)
• 2.5% THR recurrent dislocation [Cabanela Orthop 1999]
• Reoperation:– THR 4% vs. Hemi 6-18%
• DVT / PE / Mortality • no difference
• Pain / Function / Survivorship / Cost-effectiveness• THR better than Hemi [Lu –Yao JBJS 1994] [Iorio CORR 2001]
ORIF or Replacement?
• Prospective, randomized study ORIF vs. cemented bipolar hemi vs. THA
• ambulatory patients > 60 years of age– 37% fixation failure (AVN/nonunion)– similar dislocation rate hemi vs. THA (3%)– ORIF 8X more likely to require revision surgery
than hemi and 5X more likely than THA – THA group best functional outcome
Keating et al OTA 2002Keating et al OTA 2002
Stress Fractures
• Patient population:– Females 4–10 times more common
• Amenorrhea / eating disorders common• Femoral BMD average 10% less than control
subjects
– Hormone deficiency– Recent increase in athletic activity
• Frequency, intensity, or duration• Distance runners most common
Stress Fractures
• Clinical Presentation– Activity / weight bearing related – Anterior groin pain– Limited ROM at extremes– ± Antalgic gait– Must evaluate back, knee, contralateral hip
Stress Fractures
• Imaging– Plain Radiographs
• Negative in up to 66%
– Bone Scan• Sensitivity 93-100%
• Specificity 76-95%
– MRI• 100% sensitivity / specificity
• Also Differentiates: synovitis, tendon/ muscle injuries, neoplasm, AVN, transient osteoporosis of hip
Stress Fractures
• Classification– Compression sided
• Callus / fracture at inferior aspect femoral neck
– Tension sided• Callus / fracture at superior aspect femoral neck
– Displaced
Stress FracturesTreatment
• Compression sided• Fracture line extends < 50% across neck
– “stable”– Tx: Activity / weight bearing modification
• Fracture line extends >50% across neck– Potentially unstable with risk for displacement– Tx: Emergent ORIF
• Tension sided• Unstable
– Tx: Emergent ORIF
• Displaced– Tx: Emergent ORIF
Stress FracturesComplications
• Tension sided and Compression sided fx’s (>50%) treated non-operatively
• Varus malunion
• Displacement– 30-60% complication rate
• AVN 42%
• Delayed union 9%
• Nonunion 9%
Femoral Neck Nonunion
• Definition: not healed by one year• 0-5% in Non-displaced fractures• 9-35% in Displaced fractures• Increased incidence with
– Posterior comminution– Initial displacement– Inadequate reduction– Non-compressive fixation
Femoral NeckNonunion
• Clinical presentation– Groin or buttock pain– Activity / weight bearing related– Symptoms
• more severe / occur earlier than AVN
• Imaging– Radiographs: lucent zones– CT: lack of healing– Bone Scan: high uptake– MRI: assess femoral head
viability
Femoral NeckNonunion
• Treatment– Elderly patients
• Arthroplasty– Results typically not as good as primary elective
arthroplasty
• Girdlestone Resection Arthroplasty– Limited indications
– deep infection?
Femoral NeckNonunion
• Young patients (must have viable femoral head)
– Varus alignment or limb shortened
• Valgus-producing osteotomy
– Normal alignment• Bone graft / muscle-pedicle
graft
• Repeat ORIF
Osteonecrosis (AVN)Femoral Neck Fractures
• 5-8% Non-displaced fractures
• 20-45% Displaced fractures
• Increased incidence with– INADEQUATE REDUCTION– Delayed reduction– Initial displacement– associated hip dislocation– ?Sliding hip screw / plate devices
Osteonecrosis (AVN)Femoral Neck Fractures
• Clinical presentation– Groin / buttock / proximal thigh pain– May not limit function– Onset usually later than nonunion
• Imaging– Plain radiographs: segmental collapse / arthritis– Bone Scan: “cold” spots– MRI: diagnostic
Osteonecrosis (AVN)Femoral Neck Fractures
• Treatment– Elderly patients
» Only 30-37% patients require reoperation
• Arthroplasty– Results not as good as primary elective
arthroplasty
• Girdlestone Resection Arthroplasty– Limited indications
Osteonecrosis (AVN)Femoral Neck Fractures
• Treatment– Young Patients
» NO good option exists
• Proximal Osteotomy– Less than 50% head collapse
• Arthroplasty– Significant early failure
• Arthrodesis– Sugnificant functional limitations
** Prevention is the Key **
Femoral Neck FracturesComplications
• Failure of Fixation– Inadequate / unstable reduction– Poor bone quality– Poor choice of implant
• Treatment– Elderly: Arthroplasty– Young: Repeat ORIF
Valgus-producing osteotmy Arthroplasty
Femoral Neck FracturesComplications
• Post-traumatic arthrosis• Joint penetration with hardware
• AVN related
• Blood Transfusions– THR > Hemi > ORIF
– Increased rate of post-op infection
• DVT / PE– Multiple prophylactic regimens exist
– Low dose subcutaneous heparin not effective
Femoral Neck FracturesComplications
• One-year mortality 14-50%
• Increased risk:– Medical comorbidities– Surgical delay > 3 days– Institutionalized / demented patient– Arthroplasty (short term / 3 months)– Posterior approach to hip
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