Femoral Neck Fractures

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

• Greater fracture displacement = greater risk of vascular disruption to femoral head

• 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 – 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

• 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

Open Reduction or Closed Reduction?

Open reduction can be considered for any displaced femoral neck fractures that are treated with reduction and internal fixation

Open reduction is indicated after an attempt at gentle closed reduction results in a non-anatomic reduction

Primary open reduction is preferred in young patients with a displaced femoral neck fracture

Approach For Open Reduction

Smith-Peterson• Anterior approach

• Best for transcervical and subcapitol fractures

• Fixation is performed through a second approach

Approach For Open ReductionWatson-Jones• Anteriolateral exposure

• Best for basalar neck and IT patterns

• Allows placement of sliding hip screw through same incision

What Reduction Is Acceptable?

• Ideal reduction is Anatomic– Acceptable: < 15º valgus < 10º AP angulation

• Any varus is unacceptable

• 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

Screw Fixation• Screw location

– Avoid posterior/ superior quadrant» Blood supply

» Cut-out

– Biomechanical advantage to inferior/ calcar screw

[Booth 1998]

Sliding Compression Screw Fixation

• 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

Intracapsular Hematoma

• incidence- 75% have some intracapsular pressure– no difference displaced/nondisplaced

• sensitive to leg position– extension + internal rotation= bad

• animal models: intracapsular pressure = perfusion• Theoretical benefit with NO clinical proof

– but it doesn’t hurt

Case Example 42 yo male, MVC

Open reduction via Smith-Pete approach, screw fixation placed through separate incision

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– Significant 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 osteotomy 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