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 Artery of ligamentum teres 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 At risk populations 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 Unstable 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 Operative very limited role Activity modification Skeletal traction Operative ORIF Hemiarthroplasty Total Hip Replacement

Treatment Decision 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

Treatment Young 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

Treatment Elderly 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]

Treatment Pre-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

Treatment Pre-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

Treatment Pre-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

Hemi ORIF 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 No clinical advantage over parallel 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

ORIF Intracapsular 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 Fractures Hemiarthroplasty 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 Fractures Hemiarthroplasty 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]

Hemiarthroplasty Unipolar vs. Bipolar Bipolar theoretical advantages Lower dislocation rate Less acetabular wear/ protrusio Less Pain More motion

Hemiarthroplasty Unipolar vs. Bipolar Disadvantages Cost Dislocation often requires open reduction Loss of motion interface (effectively unipolar) Polyethylene wear/ osteolysis not yet studied for Bipolars

Hemiarthroplasty Unipolar 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

Hemiarthroplasty Cemented 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)

Hemiarthroplasty Cemented 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

Treatment Pre-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: Reoperation: 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]

Keating et al OTA 2002 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

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 Bone Scan MRI 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 Tension sided Callus / fracture at inferior aspect femoral neck Tension sided Callus / fracture at superior aspect femoral neck Displaced

Stress Fractures Treatment 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 Displaced

Stress Fractures Complications 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 Neck Nonunion Clinical presentation Imaging 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 Neck Nonunion Treatment Elderly patients Arthroplasty Results typically not as good as primary elective arthroplasty Girdlestone Resection Arthroplasty Limited indications deep infection?

Femoral Neck Nonunion Young patients Varus alignment or limb shortened (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 Fractures Complications 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 Fractures Complications 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 Fractures Complications 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 Index