Please confirm topic selection

Are you sure you want to trigger topic in your Anconeus AI algorithm?

Please confirm action

You are done for today with this topic.

Would you like to start learning session with this topic items scheduled for future?

Updated: Oct 26 2020

Pediatric Hip Trauma Radiographic Evaluation

 Normal Anatomy
 Ossification of the hip
 Osteology & Attachments
  • Anterior view
  • Posterior view
  • Lateral view
  • Superior view
 Radiographic Views
 AP view
  • Positioning
    • patient
      • supine
      • leg IR 15-20°
    • beam
      • aim between ASIS + symphysis pubis
  • Critique
    • no rotation of pelvis
      • superimposition of ischial spine with pelvic brim
      • open obturator foramen
    • no visualization of lesser trochanters
      • too much external rotation of leg leads to increased visualization of lesser trochanter
      • superimposition of ischial spine with pelvic brim
 Lateral view
  • Positioning 
Rolled lateral
supine hip abducted 45° + knee flexed 90° mid-femoral neck

Horizontal ray/cross-table
supine contralateral hip flexed 90° + ipsilateral hip IR 15-20° femoral head
45° cephalad
Modified Dunn supine hip flexed 45° + abducted 20° 2.5 cm above pubic symphysis n/a
Frog leg
supine hip abducted 45° + knee flexed 30-40° 2.5 cm above pubic symphysis n/a
Lowenstein semi-lateral 45° on ipsilateral side hip flexed 90° mid-femoral neck 20-25° cephalad
False profile
erect hip flexed 90°pelvis ER 65° toward ipsilateral side femoral head
  • Indications
    • horizontal ray/cross-table
      • useful in trauma patients where positioning is limited by pain
    • modified dunn
      • better demonstrates relationship of femoral head with acetabulum
      • useful for confirming femoroacetabular impingement (alpha angle)
    • frog leg
      • better demonstrates shape of femoral head + head/neck transition
      • useful for confirming epiphysiolysis, SCFE, Perthes disease
    • lowenstein
      • useful as alternative to frog leg view, as it is technically easier to obtain
    • false profile
      • provides true lateral projection of femoral head/neck and oblique view of acetabulum
      • demonstrates anterior acetabular coverage of femoral head
      • useful for determining anterior center-edge angle
  • Critique 
    • horizontal ray/cross-table
      • visualization of greater trochanter
        • increased cephalad angle leads to increased visualization of greater trochanter off femoral neck but will distort/elongate femoral neck
      • no obstructing soft tissue artifact via adequate elevation of contralateral leg
    • modified dunn
      • no overhang of greater trochanter over posterior margin
      • visualization of lesser trochanter
    • frog leg/lowenstein
      • symmetrical obturator foramen + iliac wing concavity
      • superimposition of greater trochanter + femoral neck
    • false profile
      • visualization of lesser trochanter
        • too much ER leads to nonvisualization of lesser trochanter
      • demonstration of bullet sign = superimposition of ischial tuberosity
 Oblique view
  • Positioning 
Hsieh semi-prone contralateral hip elevated 40-45° femoral head
lateral decubitus on ipsilateral side pelvis tilted anteriorly 15° greater trochanter
semi-prone contralateral hip elevated 38° 2 cm above greater trochanter
12° cephalad
  • Indications
    • hsieh = posterior hip dislocation
    • lillenfeld = posterolateral pelvis
    • teufel = fovea capitis
  • Critique
 Normal Radiographic Findings


Leg-length discrepancy
AP line along inferior ischial tuberosity + line along superior aspect of lesser trochanter
0 cm
Neck-shaft angle
AP angle between femoral neck + femoral shaft


coxa vara < 120°; coxa valga > 140°
Lateral center-edge angle/angle of wiberg
AP angle between vertical line through femoral head + line along lateral acetabulum
25-40° assesses superolateral coverage: dysplasia < 20°; overcoverage > 40° 
Femoral head extrusion index
AP % of femoral head not covered by acetabulum < 25%  dysplasia > 25%
Acetabular depth
AP relationship of ilioischial line with acetabular floor vs. femoral head lateral
coxa profunda = acetabular floor touches/medial to ilioischial line; protrusion acetabuli = femoral head touches/medial to ilioischial line  
Acetabular inclination/acetabular roof angle of tonnis   AP angle between line through inferior sourcil parallel to inter-teardrop line + line from inferior to lateral sourcil
0-10°  hip instability > 10°; pincer-type FAI < 0°
Acetabular version 
AP crossover/figure-of-8 sign = relationship of anterior + posterior rim before reaching lateral sourcil 5-25° anteverted
anteverted = no crossover; retroverted = crossover, also deficient posterior wall (femoral head lateral to posterior acetabulum) + prominent ischial spine, increased by increased pelvic tilt/rotation
Hip center position
distance from medial femoral head to ilioischial line  < 10 mm  lateralized > 10 mm
Joint space width
AP weightbearing minimum distance between femoral head + acetabulum 4 mm  OA < 4 mm
Head-neck offset
AP vs. lateral relationship of anterior + posterior femoral head-neck junction symmetric radius of curvature decreased = anterior concavity > posterior; increased = anterior convexity
Head-neck offset ratio
lateral distance between line parallel to femoral neck through anterior femoral neck + anterior femoral head divided by diameter of femoral head > 0.15 cam lesion < 0.15
Alpha angle lateral angle between line from femoral head to anterolateral head-neck junction (where radius of femoral head becomes larger than neck) + line through femoral head/neck < 42° Cam lesion > 50-55°
Head sphericity
AP + lateral displacement of femoral head from reference circle < 2 mm aspherical > 2 mm
Anterior center-edge angle/angle of lequesne
false profile angle between vertical line through femoral head + line along femoral head/anterior acetabulum > 20° assesses anterior coverage; can have crossover sign but no posterior wall deficiency


 Radiographic Clinical Pearls
 Pediatric Hip Dislocation  
  • Classification
    • anterior 
      • pubic/superior = extended + ER
      • obturator/inferior = flexed + abducted + ER
    • posterior = flexed + adducted + IR
    • direct inferior/infracotyloid = luxatio erecta femoris
  • Recommended views
    • AP
      • most can be diagnosed on AP pelvis films
    • lateral
      • used to differentiate between anterior vs. posterior dislocation
      • scrutinize femoral neck to rule out fracture prior to attempting closed reduction
    • post reduction films
      • necessary to inspect for joint incongruity or nonconcentric reduction   
  • Findings
    • loss of congruence of femoral head with acetabulum   
  • Treatment criteria
    • nonoperative treatment acceptable in most cases
    • open reduction if
      • nonconcentric reduction 
      • intra-articular fragment
      • unstable acetabular rim fracture
      • irreducible by closed means
 Pediatric Proximal Femur Fractures 
  • Classification = Delbet
    Delbet Classification  
     Type Description Incidence AVN Nonunion  Images
    Type I Transphyseal (subclassify as without [IA] or with [IB] dislocation of epiphysis from acetabulum) <10%
    Type II Transcervical 40-50%
    28% 15%   
    Type III Cervicotrochanteric (or basicervical) 30-35% 18% 15-20%   
    Type IV Intertrochanteric 10-20% 5% 5%   
  • Recommended views
    • AP
    • cross-table lateral
  • Findings
    • break/offset of bony trabeculae near Ward triangle
      • indicates nondisplaced or impacted fracture
  • Treatment criteria
    • nonoperative treatment acceptable if nondisplaced type IA, II, III, IV AND < 4 years old
    • CRPP if displaced type IA, II, III or > 4 years old
    • ORIF if type IB
    • hip screw if displaced type IV or > 4 years old
Private Note

Attach Treatment Poll
Treatment poll is required to gain more useful feedback from members.
Please enter Question Text
Please enter at least 2 unique options
Please enter at least 2 unique options
Please enter at least 2 unique options