Femoral Neck Fractures Brian Boyer, MD. Anatomy Physeal closure age 16 Neck-shaft angle 130° ± 7°...

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


• 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


• 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


• Bipolar– Disadvantages

• Cost

• Dislocation often requires open reduction

• Loss of motion interface (effectively unipolar)

• Polyethylene wear/ osteolysis not yet studied for Bipolars


– 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


• 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


• Treatment– Elderly patients

• Arthroplasty– Results typically not as good as primary elective

arthroplasty

• Girdlestone Resection Arthroplasty– Limited indications

– deep infection?


• 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


• 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


• Treatment– Elderly patients

» Only 30-37% patients require reoperation

• Arthroplasty– Results not as good as primary elective

arthroplasty

• Girdlestone Resection Arthroplasty– Limited indications


• 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


• 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


• 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

Return to Lower Extremity

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Femoral Neck Fractures Brian Boyer, MD. Anatomy Physeal closure age 16 Neck-shaft angle 130° ± 7°...

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