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Updated: Sep 24 2024

Intertrochanteric Fractures

Images
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  • Summary
    • Intertrochanteric Fractures are common extracapsular fractures of the proximal femur at the level of the greater and lesser trochanter that are most commonly seen following ground-level falls in the elderly population.
    • Diagnosis is made with orthogonal radiographs of the hip. MRI is most helpful to evaluate occult hip fractures.
    • Treatment is generally operative with sliding hip screw versus cephalomedullary nail depending on fracture stability. 
  • Epidemiology
    • Incidence
      • account for ~50% of hip fractures 
      • 150,000 intertrochanteric fractures per year in US
      • 500 per 100,000 population per year for elderly female
      • 200 per 100,000 population per year for elderly male
    • Demographics
      • age
        • average ~80 years old
          • typically older age than femoral neck fractures
      • female: male ratio between 2:1 and 8:1
    • Risk factors 
      • proximal humerus fractures increase risk of hip fracture for 1 year
      • osteoporosis
      • advancing age
      • increased number of comorbidities
      • increased dependency with ADLs
  • Etiology
    • Pathophysiology
      • mechanism
        • elderly
          • low energy falls in osteoporotic patients
        • young
          • high energy trauma
    • Associated conditions
      • osteoporosis
      • recurrent falls
        • dementia
        • parkinsons
        • unsteady gait
        • visual impairment
        • medications
  • Anatomy
    • Osteology
      • neck shaft angle 130 +/- 7 degrees
      • anteversion 10 +/- 7 degrees
      • intertrochanteric area exists between greater and lesser trochanters
      • calcar femorale
        • vertical wall of dense bone that extends from posteromedial aspect of femoral shaft to posterior portion of femoral neck
        • level of involvement helps determine stable versus unstable fracture patterns
      • radius of curvature of femur
        • average 114-120 cm
        • factors that decrease radius of curvature (increased bowing)
          • elderly
          • asian 
          • short stature
    • Muscles
      • deforming forces on proximal segment
        • flexion
          • iliopsoas
          • sartorius
          • rectus femoris
          • pectineus
        • external rotation
          • piriformis
          • superior gemellus
          • obturator internus
          • inferior gemellus
          • quadratus femoris
        • abduction
          • gluteus maximus
          • gluteus medius
          • gluteus minimus
          • tensor fascia lata
      • deforming forces on distal segment
        • adduction and shortening
          • adductor longus
          • adductor brevis
          • adductor magnus
          • gracilis
        • overall varus alignment
    • Blood supply
      • rich collateral circulation reduces risk of nonunion 
        • trochanteric anastomosis
          • ascending branch of medial circumflex femoral artery (MFCA)
          • ascending branch of lateral circumflex femoral artery (LFCA) 
          • deep branch of superior gluteal artery
          • inferior gluteal artery
        • transverse branch of LFCA and MFCA
        • periosteum and surrounding muscles 
    • Biomechanics
      • Ward's triangle
        • area of lowest BMD in femoral neck bordered by 3 main compressive/tensile trabeculae
          • primary compressive trabeculae
            • extends from medial femoral head along calcar and excellent support to proximal femur
            • vertically oriented with a triangular configuration
          • principal tensile trabeculae 
            • forms an arc through the superior cortex of the femoral head and neck
            • extends from greater trochanter to inferior aspect of femoral head below fovea
          • secondary compressive trabeculae
            • fan-like configuration crossing from greater trochanter to lesser and also comprises calcar
  • Classification
    • Stability  
      • most commonly used and reliable classification 
      • two types
        • stable
          • definition
            • intact posteromedial cortex
          • clinical significance
            • will resist medial compressive loads once reduced
        • unstable
          • definition
            • fracture will collapse into varus or shaft will displace medially 
          • examples
            • large or comminuted posteromedial cortex
              •  i.e. lesser trochanteric fragment 
            • reverse obliquity or transtrochanteric 
              • fracture line extending from medial cortex out through lateral cortex
            • subtrochanteric extension 
          • other considerations
            • lateral wall thickness
              • measured from 3 cm distal from innominate tubercle at 135 degrees to the fracture site
                • <20.5 mm suggest risk of postoperative lateral wall fracture
                  • should be treated with cephalomedullary nail (CMN) rather than sliding hip screw (SHS)
              • key role in stabilizing proximal femur by providing lateral buttress  
      • AO/OTA Classification
      • 31A -A1
      • peritrochanteric simple two part
      • intact lateral cortex
      • 31A-A2
      • pertrochanteric with separate posteromedial fragment
      • intact lateral cortex
      • 31A-A3
      • fracture extends through lateral and medial cortex 
      • Evans classification (based on post-reduction stability)
      • Stable fracture 
      • posteromedial cortex intact or minimal comminution
      • able to resist compressive loads
      • Unstable fracture
      • greater comminution of posteromedial cortex 
      • can be converted to a stable pattern if medial cortical opposition obtained
      • Reverse obliquity
      • unstable due to medial displacement of femoral shaft due to adductors
  • Presentation
    • History
      • mechanism of injury 
        • low-energy most common in elderly
        • higher-energy may be associated with other injuries
      • pre-injury functional status
        • predictor of postoperative functional status 
      • antecedent hip pain
        • presence of OA or pathological fracture 
      • history of anticoagulation 
        • factors into surgical timing 
      • list of comorbidites (ASA classification) 
    • Symptoms
      • acute onset of hip pain
      • inability to ambulate
    • Physical Exam
      • inspection 
        • shortened, externally rotated lower extremity
      • palpation
        • tenderness over greater trochanter
      • motion
        • pain with log roll and axial load
        • unable to perform active straight leg raise
      • assess thigh compartments
      • neurovascular assessment 
  • Imaging
    • Radiographs
      • recommended views
        • AP pelvis
        • AP hip
        • cross table lateral
        • full length femur
      • optional
        • traction internal-rotation view
          • improve accuracy of fracture classification with direct impact on surgical planning 
      • findings 
        • AP pelvis
          •  compare to contralateral hip and assess neck shaft angle
        • AP hip
          • defines fracture pattern 
        • cross-table lateral
          • helps assess for posterior cortex comminution
        • full length femur 
          • assess subtrochanteric extension
          • possibility of pathological fracture
          • estimate length of intramedullary nail
          • assess femoral bowing
          • assess canal diameter
    • CT 
      • indication 
        • second line imaging to evaluate for occult fracture 
          • no access or contraindication to MRI
      • views
        • thin, 1-2 mm slice cuts 
      • diagnostic accuracy 
        • sensitivity 86%
        • specificity 98%
    • MRI
      • indication
        • occult hip fracture 
          • AAOS recommendation: moderate strength 
        • isolated greater trochanteric fracture to evaluate for intertrochanteric extension
      • findings 
        • bone marrow edema STIR or fat-suppressed T2
        • line of decreased intensity on T1 coronal view corresponding with signal on T2 and STIR
      • diagnostic accuracy
        • sensitivity 
          • T1-weighted 100% (most sensitive) 
          • T2-weighted 84%
    • Bone scan
      • indication
        •  contraindication to MRI
          • rarely used
            • improved access to MRI and CT
            • delay in care
            • false negative up to 72 hours from injury
      • diagnosis accuracy
        • variable with sensitivity up to 98%
  • Treatment
    • Nonoperative
      • protected weight bearing
        • indications
          • nonambulatory patients
          • high risk for perioperative mortality
          • skin breakdown at surgical site
          • incomplete fractures
        • techniques
          • non-weight bearing with early mobilization from bed to chair
        • outcomes
          • high mortality rate
            • 84.4% at 1-year
          • higher rates of pneumonia, UTI, decubitus ulcers, and DVT
          • low risk of displacement with occult fracture 
    • Operative
      • closed reduction and intramedullary nail fixation (IMN)
        • indications
          • stable fracture patterns
            • AAOS recommendation: strong for use of either SHS or CMN
          • unstable fracture patterns
            • AAOS recommendation: strong for use of CMN 
          • reverse obliquity fractures
            • AAOS recommendation: strong for use of CMN 
            • 56% failure rate when treated with SHS
          • subtrochanteric extension
            • AAOS recommendation: strong for use of CMN 
          • lack of integrity of femoral wall
            • associated with increased displacement and collapse when treated with SHS
            • increased risk of lateral wall fracture with decreasing lateral wall thickness
        • technique
          • cephalomedullary (CMN) device indicated in IT fractures
            • short CMN
            • long CMN
        • outcomes
          • stable fracture pattern 
            • similar clinical and radiographic outcomes for SHS vs CMN 
          • unstable fracture pattern 
            • lower reoperation rate with CMN  
          • CMN use has significant increased over last decade
      • open reduction and internal fixation (ORIF)
        • indications
          • stable fracture pattern
            • AAOS recommendation: strong for use of either SHS or CMN 
        • techniques
          • sliding hip compression (SHS) screw (most common)
          • proximal femur locking plate
          • 95 degree blade plate (rarely used) 
        • outcomes
          • similar outcomes for stable fracture patterns when compared to CMN
      • arthroplasty
        • indications (rare) 
          • salvage for failed internal fixation
          • severely comminuted fractures
          • preexisting severe degenerative hip arthritis
          • severely osteoporotic bone that is unlikely to hold internal fixation
  • Techniques
    • Closed reduction with intramedullary fixation (IMN)
      • indications
        • pros vs. ORIF
          • biologically friendly with potentially closed technique
          • less estimated blood loss (EBL)
          • can be used in unstable fracture patterns
          • decreased bending strain on implant
            • load sharing device with shorter lever arm on implant
            • intramedullary buttress limits shaft medialization  
        • cons vs. ORIF
          • periprosthetic fracture
          • higher implant cost than ORIF with sliding hip screw
          • violation of hip abductors for insertion
      • approach
        • supine on fracture table 
        • lateral decubitus on radiolucent table
      • technique
        • short vs long CMN
          • controversial 
            • AAOS recommendation: limited  
          • short CMN
            • advantage
              • ease of use
              • decreased OR time
              • decreased EBL
              • lower implant cost
          • long CMN
            • advantage
              • theoretical benefit of protecting entire femur
            • disadvantage
              • increased OR time
              • increased EBL
              • increased postoperative blood transfusion 
              • increased radiation exposure
              • possible mismatch of implant bow and femur
          • outcomes 
            • similar functional outcomes, peri-implant fracture, and cutout rate 
              • short nail can tolerate up to 3-4 cm of subtrochanteric extension
        • lag screw versus helical blade
          • controversial 
          • lag screw
            • proven track record
            • femoral head rotation during insertion
          • helical blade 
            • theoretical benefit of compacting cancellous bone around blade during insertion
              • avoids removal of bone with reamer
            • biomechanical studies showing higher cutout resistance
      • complication
        • lag screw or helical blade cutout
          • cut-out defined as anterocranial perforation of the femoral head by the blade/screw with subsequent varus collapse
          • cut-through defined as central perforation of the femoral head by the blade/screw without subsequent collapse
            • helical blade constructs have much higher rates of cut-through when compared to lag screw constructs
        • anterior perforation of femur
        • perimplant fracture 
    • Open reduction and internal fixation (ORIF)
      • techniques
        • sliding hip compression screw
          • technique
            • must obtain correct neck-shaft relationship
            • lag screw with tip-apex distance <25 mm is associated with reduced failure rates
            • 4 hole plates show no benefit clinically or biomechanically over 2 hole plates
          • pros
            • allows dynamic interfragmentary compression
            • lower implant cost
            • no violation of hip abductors
          • cons
            • open technique
            • increased blood loss
            • not advisable in unstable fracture patterns
              • excessive fracture collapse
              • limb shortening
              • medialization of shaft
            • anterior spike malreduction in left-sided, unstable fractures due to screw torque
              • place derotational wire or screw prior to lag screw insertion
        •  proximal femoral locking plate
          • indication
            • infrequently used
              • consider in young patient with unstable fracture
          • pros 
            • allow for intraoperative fracture compression 
            • avoid excessive postoperative fracture compression
            • maintain limb length
            • avoid shaft medicalization 
          • cons
            • limited evidence
            • highly dependent on surgeon experience 
            • must obtain anatomic reduction 
    • Arthroplasty
      • technique
        • long stem with calcar-replacing prosthesis often needed
        • must attempt fixation of greater trochanter to shaft
      • pros
        • possible early return to unrestricted weight bearing
        • not reliant on internal fixation in osteoporotic bone
      • cons
        • increased blood loss and OR time
        • increased cost
        • may require prosthesis that some surgeons are less familiar with
  • Complications
    • Implant failure and cutout
      • incidence
        • occurs in 4-20%
        • usually occurs within first 4 months
      • risk factors
        • older age
        • osteoporosis
        • fracture type
        • quality of reduction 
        • tip-apex distance (TAD)
          • sum of distances from tip of lag screw to apex of femoral head on AP and lateral
            • after adjusting for magnification
          • goal TAD <25mm 
          • TAD >45 mm associated with 60% failure rate
      • treatment
        • young
          • corrective osteotomy and/or revision open reduction and internal fixation
        • elderly or articular injury from screw cutout
          • total hip arthroplasty
    • Nonunion and malunion 
      • incidence
        • <2%
          • uncommon due to good blood supply
        • varus malreduction can occur with excessively lateral starting point (>3mm)
          • leads to varus collapse and screw cutout 
      • diagnosis
        • hip pain with persistent radiolucent defect at fracture site 4-7 months after surgery
        • CT scan may help confirm diagnosis
        • rule out infection 
      • treatment
        • valgus intertrochanteric osteotomy + bone grafting
        • arthroplasty 
          • screw cutout has damaged hip joint
    • Peri-implant fracture
      • incidence 
        • 1-3% at 1 year
        • no significant difference between short and long CMN
        • short CMN typically fracture just distal to tip of nail
        • long CMN typically fracture more around the rod (as opposed to the tip) 
      • risk factors 
        • distal interlocking screw protective against fracture 
      • treatment
        • short CMN
          • distally inserted lateral femoral plate with cables
          • revise to long CMN
        • long CMN
          • closed reduction and insertion of distal locking screw
          • distal femoral plating (fracture distal to tip)
    • Anterior perforation of the distal femur
      • incidence
        • mostly seen with insertion of long CMN
        • decreased with improvements in nail radius of curvature to better match patient anatomy
      • risk factors
        • mismatch of the radius of curvature of the femur (shorter) and implant (longer)
        • posterior starting point on the greater trochanter
    • Postoperative anemia and transfusions
      • blood transfusion
        •  >30% postoperative transfusion rate
        • AAOS moderate recommendation 
          • transfusion threshold no higher than 8g/dL in asymptomatic postop hip fracture
      • transexamic acid (TXA) 
        • AAOS strong recommendation for use 
        • decrease EBL 
        • decrease postoperative blood transfusion 
  • Prognosis
    • General considerations
      • Anesthesia type (spinal vs. general)
        • No difference in postoperative delirium, mortality and ambulatory function at 60 days 
    • Mortality 
      • 15-30% mortality risk in the first year following fracture
      • 84.4% at one year with nonoperative treatment 
    • Factors that increase mortality
      • male gender (25-30% mortality) vs female (20% mortality)
      • higher in intertrochanteric fracture (vs femoral neck fracture)
      • operative delay of >2 days
      • age >85 years
      • 2 or more pre-existing medical conditions
      • ASA classification (ASA III and IV increases mortality)
    • Factors that decrease mortality
      • Surgery within 48 hours decreases 1 year mortality
        • AAOS moderate recommendation for hip fracture surgery within 24-48 hours of admission
      • early medical optimization and co-management with medical hospitalists or geriatricians 
        • AAOS strong recommendation for use of interdisciplinary care teams
        • In the absence of clear risk factors for valvular disease, arrhythmias, worsening heart failure, or coronary artery stenosis, an echocardiogram is unlikely to change peri-operative complications and has been shown to delay time to surgical fixation
    • Loss of independence 
      • community-dwelling ambulators at 1-year 
        • 41% maintain pre-injury ambulatory status
        • 40% more dependent on assistive devices
        • 12% became household ambulators
        • 8% became nonfunctional ambulators
      • One-third general rule
        • 1/3 regain function
        • 1/3 lose one level of independence
        • 1/3 mortality rate  
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