John Au Liz Abbott Dr Diana Perriman Prof. Paul Smith AO Classification of Pelvic Ring Fracture Educational Package 2013 (version 2) John Au Liz Abbott Dr Diana Perriman Prof. Paul Smith

= Need to know Need to know = For your interest For your interest

Why Classify? Accurate identification and classification of pelvic fracture guides treatment, is potentially crucial to patient survival and is necessary for data collection.

Pelvic Fractures can be divided into: 1) Acetabular Fractures AO Classification Letournel & Judet Classification 2) Pelvic Ring Fractures Young & Burgess Classification 3) Sacral Fractures Denis Classification

Pelvic Fractures classification systems include: 1) Acetabular Fractures AO Classification Letournel & Judet Classification 2) Pelvic Ring Fractures Young & Burgess Classification 3) Sacral Fractures Denis Classification Isler Classification

At Canberra Hospital and Internationally: 1) Acetabular Fractures AO Classification Letournel & Judet Classification 2) Pelvic Ring Fractures Young & Burgess Classification 3) Sacral Fractures Denis Classification Need to know Know how to classify acetabular # & pelvic ring # using X-rays & CT scans

AO classification

AO Classification: 5 components

A 1 1 B 2 2 C 3 3 AO Classification: 5 components Bone Segment Fracture Type Fracture Group Fracture Subgroup A 1 1 B 2 2 C 3 3

A 1 1 B 2 2 C 3 3 # Localisation # Morphology Bone Segment Fracture Type Fracture Group Fracture Subgroup A 1 1 B 2 2 C 3 3

Now focusing on Pelvic Ring fractures

AO classification Young & Burgess classification Pelvic Ring Fracture AO classification Young & Burgess classification

AO classification Young & Burgess classification Need to know Pelvic Ring Fracture AO classification Young & Burgess classification

Need to know With respect to pelvic ring #, there are some definitions to keep in mind.

Pelvic ring has two arches: (a) Posterior arch is behind acetabular surface and includes sacrum, sacroiliac joints and their ligaments and posterior ilium, and (b) Anterior arch is in front of acetabular surface and includes pubic rami bone and symphyseal Joint. Orthopaedic Trauma Association Classification, Database and Outcomes Committee (2007) Fracture and Dislocation Classification Compendium, JOT, 21(10), supplement

Unilateral: only 1 hemipelvis involved posteriorly Bilateral: both hemipelvis involved posteriorly Contralateral: side opposite the major posterior lesion Ipsilateral: the side of the more severe lesion Orthopaedic Trauma Association Classification, Database and Outcomes Committee (2007) Fracture and Dislocation Classification Compendium, JOT, 21(10), supplement

AO Classification: Pelvic Ring Bone Segment Fracture Type Fracture Group Fracture Subgroup A 1 1 61 = pelvic ring B 2 2 C 3 3

AO Classification: Pelvic Ring Bone Segment Fracture Type Fracture Group Fracture Subgroup A 1 1 B 2 2 C 3 3

Need to know A B C

AO Classification is based on fracture stability Need to know AO Classification is based on fracture stability

= = = A B C STABLE PARTIALLY STABLE UNSTABLE Lesion sparing the posterior arch; pelvic floor intact and able to withstand normal physiological stresses without displacement = PARTIALLY STABLE Posterior osteoligamentous integrity partially maintained and pelvic floor intact = UNSTABLE Complete loss of posterior osteoligamentous integrity; pelvic floor disrupted A B C

are more frequently associated with HAEMORRHAGE pelvic # are more frequently associated with HAEMORRHAGE UNSTABLE

Therefore, it is important NOT to miss an unstable #

“Although the anterior structures, the symphysis pubis and the pubic rami, contribute approximately 40% to the stiffness of the pelvis, clinical and biomechanical studies have shown that the posterior sacroiliac complex is more important to pelvic-ring stability.” “Therefore, the AO classification of pelvic fractures is based on the stability of the posterior lesion.”

Anatomy Review Posterior Anterior Ligamentous structures are major contributors to the stability of the posterior arch Iliolumbar Ligament Posterior Anterior Posterior Sacroiliac Ligaments Anterior Sacroiliac Ligament Sacrospinous Ligament SacrotuberousLigament

AO Classification: Pelvic Ring Bone Segment Fracture Type Fracture Group Fracture Subgroup A 1 1 B 2 2 C 3 3

A = no pelvic ring instability Need to know A A B C A = no pelvic ring instability

Need to know A B B C B = Rotationally unstable but Vertically stable

Need to know A B C C C = Grossly Unstable

AO Classification: Pelvic Ring Bone Segment Fracture Type Fracture Group Fracture Subgroup A 1 1 B 2 2 C 3 3

A = no pelvic ring instability

For your interest A A B C

For your interest A A B C

For your interest A A B C

A B B C B = Rotationally unstable but Vertically stable

For your interest A B B C

For your interest A B B C

For your interest A B B C

A B C C C = Grossly Unstable

For your interest A B C C

For your interest A B C C

For your interest A B C C

For your interest

In Summary

Stable Rotationally unstable, vertically stable Rotationally unstable, Need to know TYPE GROUP HEMIPELVIS DISPLACEMENT STABILITY Type A Intact posterior arch A1, Pelvic Ring fracture (avulsion) None Stable A2, Pelvic Ring fracture (direct blow) A3, Transverse Sacral fracture Type B Partial posterior arch disruption B1, Open-book injury; Unilateral partial posterior arch disruption External rotation Rotationally unstable, vertically stable B2, Lateral Compression, Unilateral partial posterior arch disruption Internal rotation B3, Bilateral partial posterior arch disruption Bilateral Type C Complete posterior arch disruption C1, Unilateral complete posterior arch disruption Vertical (cranial)   Rotationally unstable, vertically unstable (Grossly Unstable) C2, Ipsilateral complete, contralateral incomplete posterior arch disruption Ipsilateral vertical (cranial), contralateral internal or external rotation C3, Bilateral complete posterior arch disruption Bilateral vertical (cranial) Modified from: https://www2.aofoundation.org/wps/portal/!ut/p/c0/04_SB8K8xLLM9MSSzPy8xBz9CP0os3hng7BARydDRwN39yBTAyMvLwOLUA93I4MQE_2CbEdFAF3RnT4!/?segment=Ring&bone=Pelvis&soloState=true&popupStyle=diagnosis&contentUrl=srg/popup/decision_support/61-Emergency/Tile_classification.jsp

Part 3: Sacral Fractures For your interest

Part 3: Sacral Fractures For your interest Part 3: Sacral Fractures Denis classification Isler classification

Part 3: Sacral Fractures For your interest Part 3: Sacral Fractures Denis classification Isler classification

For your interest Denis, F., Davis, S. & Comfort, T. (1988) Sacral Fractures: An Important Problem. Retrospective Analysis of 236 Cases. CORR 227: 67-81

Zone 1 Zone 2 Zone 3 # Location Frequency of neurologic injury For your interest # Location Frequency of neurologic injury Zone 1 The region of the ala (Lateral to the sacral foramina) 5.9 percent, usually L5 root Zone 2 The region of the sacral foramina 28.4 percent, predominately sciatica with rare bladder or bowel involvement Zone 3 The central sacral canal region (Medial to the sacral foramina) ≥50 percent; most involve bowel, bladder, or sexual dysfunction Denis, F., Davis, S. & Comfort, T. (1988) Sacral Fractures: An Important Problem. Retrospective Analysis of 236 Cases. CORR 227: 67-81

X-rays & CTs

Inlet view (Pelvic Ring #) Inlet Views is good for assessing: AP shear/Translation of hemipelvis Iliac Spines Source: Up to date

Inlet view Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

Outlet view (Pelvic Ring #) Outlet Views is good for assessing: Vertical shear & translation Obturator Foramina Sacral Foramina Source: Up to date

Outlet view

Sacral Arcuate Lines (eyebrows) The arcuate lines represent the inferior surfaces of the costal elements that form the roofs of the anterior sacal canals (foramina) and neural grooves Sacral Arcuate Lines (eyebrows) Jackson, H., Kam, J., Harris, J.H. & Harle, T.S. (1982) The sacral arcuate lines in upper sacral fractures. Radiology 145, 35-39

CT reconstruction CT reconstruction is a powerful tool for imaging difficult #’s.

How should pelvic ring # X-rays be approached?

X-ray interpretation Be systematic Front to back, then as a whole Need to know Be systematic Front to back, then as a whole Anterior structures Posterior sturctures Pelvic Ring Hemipelvis

X-ray interpretation Anterior Pubic Symphysis Rami Femur Need to know Anterior Pubic Symphysis Rami Femur Iliac Crests & Wings ASIS & AIIS Normal Pelvic X-ray

Widened pubic symphysis X-ray interpretation Need to know Anterior Pubic Symphysis widening? overlap? Vertical alignment: is it in line with tip of coccyx in the midline? Normal symphysis: 4 to 5mm in width & does not exceed 1cm Rami Obturator Ring: disruption? Femur Head, Neck, GT, LT & shaft #? hip dislocation? Iliac Crests & Wings #? ASIS & AIIS Avulsion #? Widened pubic symphysis Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

Sclerotic line representing iliac wing # X-ray interpretation Need to know Anterior Pubic Symphysis widening? overlap? Vertical alignment: is it in line with tip of coccyx in the midline? Normal symphysis: 4 to 5mm in width & does not exceed 1cm Rami Obturator Ring: disruption? Femur Head, Neck, GT, LT & shaft #? hip dislocation? Iliac Crests & Wings #? ASIS & AIIS Avulsion #? Sclerotic line representing iliac wing # Superior pubic ramus # Inferior pubic ramus # Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

X-ray interpretation Avulsion ASIS fragment Anterior Pubic Symphysis Need to know Anterior Pubic Symphysis widening? overlap? Vertical alignment: is it in line with tip of coccyx in the midline? Normal symphysis: 4 to 5mm in width & does not exceed 1cm Rami Obturator Ring: disruption? Femur Head, Neck, GT, LT & shaft #? hip dislocation? Iliac Crests & Wings #? ASIS & AIIS Avulsion #? Avulsion ASIS fragment Avulsion ASIS fragment Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

X-ray interpretation Posterior Sacroiliac joint Sacrum L5 TP Need to know Posterior Sacroiliac joint Sacrum L5 TP Normal Pelvic X-ray

X-ray interpretation Posterior Sacroiliac joint (SIJ) Sacrum Need to know Posterior Sacroiliac joint (SIJ) Widening? Hinging? Vertical Shear? Overlap? joints should be symmetrical joint space less than 2 to 4mm in width Sacrum #? Sacral arcuate lines (eyebrows) – disruptions? Which zone? 1, 2 or 3? (implications for neurological involvement) L5 TP (attachment of the iliolumbar ligament) “A fracture of the transverse process of L5 in the presence of a pelvic fracture is associated with an increased risk of instability of the pelvic fracture” (Starks et al. 2011, JBJS Br) Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

X-ray interpretation Posterior Sacroiliac joint (SIJ) Normal SIJ Need to know Posterior Sacroiliac joint (SIJ) Normal SIJ Widened SIJ Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

Widened Pubic Symphysis X-ray interpretation Need to know SIJ diastasis Widened Pubic Symphysis Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

X-ray interpretation Pelvic Ring Need to know Pelvic Ring Follow ring formed by the inferior portion of the sacrum and the medial ilium and ischium, sweeping down the pubic bone to the pubic symphysis and back up the opposite side. This should follow a continuous ring. Normal Pelvic Ring Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

X-ray interpretation Hemipelvis UNSTABLE Need to know Hemipelvis Cranial displacement is consistent with a vertical shear # Vertical Shear # Vertically unstable, Rotationally unstable UNSTABLE Cranial displacement of the right hemipelvis Pubic Rami # Slater, S.J. & Barron, D.A. (2010) Pelvic Fractures – a guide to classification and management, 74, 16-23.

How should pelvic ring # CTs be approached?

CT interpretation Be systematic Need to know Be systematic For axial CTs, top to bottom, 3 locations: L5 vertebrae Iliac Wing Inferior Pelvis

CT interpretation L5 vertebrae (axial view) Need to know L5 vertebrae (axial view) L5 Transverse Process (attachment of the iliolumbar ligament) L5 TP #? Iliolumbar ligament is the last ligament to fail in disruptions to the posterior sacroiliac complex in pelvic ring # “A fracture of the transverse process of L5 in the presence of a pelvic fracture is associated with an increased risk of instability of the pelvic fracture” (Starks et al. 2011, JBJS Br) UNSTABLE Mulligan, M. & Talmi, D. (2009). Are pelvic radiographs needed in assault victims? Emerg Radiol 16(4): 299-301

CT interpretation Iliac wing (axial view) SIJ Ilium Sacrum Need to know Iliac wing (axial view) SIJ Ilium Sacrum

CT interpretation Iliac wing (axial view) SIJ Ilium Sacrum Need to know Iliac wing (axial view) SIJ Disruptions? e.g. Widening? Hinging? Ilium #? Avulsion #? Sacrum Vertical shear? Which zone is it in? Widened right SIJ Normal left SIJ

Unilateral complete disruption of posterior arch CT interpretation Need to know Iliac wing (axial view) SIJ Disruptions? e.g. Widening? Hinging? Ilium #? Avulsion #? Sacrum Vertical shear? Which zone is it in? UNSTABLE Unilateral complete disruption of posterior arch Widened right SIJ

CT interpretation Iliac wing (axial view) SIJ Ilium Sacrum Need to know Iliac wing (axial view) SIJ Disruptions? e.g. Widening? Hinging? Ilium #? Avulsion #? Sacrum Vertical shear? Which zone is it in? Normal Iliac wing Iliac wing #

Unilateral complete disruption of posterior arch CT interpretation Need to know Iliac wing (axial view) SIJ Disruptions? e.g. Widening? Hinging? Ilium #? Avulsion #? Sacrum Vertical shear? Which zone is it in? UNSTABLE Unilateral complete disruption of posterior arch Sacral #

CT interpretation Inferior pelvis (axial view) Ischial Tuberosities Need to know Inferior pelvis (axial view) Ischial Tuberosities Pubic Symphysis Pubic Rami Coccyx

Widened pubic Symphysis CT interpretation Need to know Inferior pelvis (axial view) Ischial Tuberosities #? Symmetry? Pubic Symphysis widening? overlap? Pubic Rami Coccyx Widened pubic Symphysis

Minimally displaced right superior pubic ramus # CT interpretation Need to know Inferior pelvis (axial view) Ischial Tuberosities #? Symmetry? Pubic Symphysis widening? overlap? Pubic Rami Coccyx Minimally displaced right superior pubic ramus #

Normal inferior pubic ramus CT interpretation Need to know Inferior pelvis (axial view) Ischial Tuberosities #? Symmetry? Pubic Symphysis widening? overlap? Pubic Rami Coccyx Normal inferior pubic ramus Inferior pubic ramus # Pubic rami # Spike # could pierce bladder (suggestive of internal rotation: B2) Transverse # (suggestive of external rotation, B1 ‘open book’)

NOTE: Even though we have divided the educational package into pelvic ring & acetabular #s, the two types of #s can occur together. Therefore, in clinical practice, you need to assess the landmarks for both acetabular* & pelvic ring #s * See acetabular # educational package

For Example UNSTABLE Complete disruption SIJ Complete disruption SIJ Acetabular # Femoral Head Fracture Inferior pubic ramus # Inferior pubic ramus #

When there are more than 1 #s in the pelvis, you would classify the #s in that patient based on the individual #s (e.g. Right 61B1 & Left 61A1). However, the main # is the more severe one.

Now, Classifying Pelvic-ring fractures using X-rays & CTs

Is this X-ray normal? Source: up to date Courtesy of Jim Fiechtl, MD

61 A1 AP Pelvic X-ray Avulsion # of Left ASIS Common in immature skeleton Think about origin of muscles ASIS avulsion # Sartorius (small avulsion) TFL (bigger avulsion) or both AIIS avulsion # Rectus Femoris 61 A1 Source: up to date Courtesy of Jim Fiechtl, MD

? Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

Avulsion fragment of AIIS X-ray Avulsion # of Right AIIS Avulsion fragment of AIIS 61 A1 Broder, J. (2011) Diagnostic Imaging for the Emergency Physician – Chapter 13 Imaging of the pelvis and hip, 706-747

61 A3 X-ray Transverse sacral # Transverse Sacral # This is an isolated transverse fracture of the sacrum, approximately at the level of the inferior margin of the left SIJ. This runs through the neural foramen of the sacrum, so that the arcuate lines of the foramen do not form a complete circle. Because the fracture only separates the caudad portion of the sacrum from the cephalad portion, the sacrum continues to form a complete bridge between the iliac wings, and the pelvis remains stable. X-ray Transverse sacral # Transverse Sacral # Transverse Sacral # 61 A3

At least a Type B X-ray Widening of pubic symphysis Therefore, open book # Therefore, at least type B However, difficult to classify because of incomplete information (e.g. completeness of posterior arch disruption? involvement of one or both sides?) At least a Type B NB: diastasis at the pubic symphysis can cause significant haemorrhage. Emergent treatment consists of closing the # and stabilising the pelvis by applying a pelvic binder or tying a sheet tightly around the lower pelvis Source: up to date

61 B1 Schematic X-ray CT Widening of pubic symphysis Schematic representation of Pubic Symphysis disruption Ligamentous disruption X-ray Widening of pubic symphysis (Therefore not a type A, at least a type B) 61 B1 CT Partial disruption of posterior arch (Therefore type B) Unilateral (Therefore B1) Source: up to date

61 B2 X-ray (A) X-ray (B) X-ray (C) Bilateral sup. & inf. rami # Left Sacral # Lateral compression injury with internal rotation of the hemiplevis No vertical shear (Therefore not type C) No pubic symphysis diastasis (Therefore not B1) X-ray (B) Inlet view showing greater detail of the pelvic ring disruption X-ray (C) Outlet view showing greater detail of the sacral # & the bilateral rami # 61 B2 Source: up to date Courtesy of Jim Fiechtl, MD

Rotationally unstable but Vertically stable X-ray Widening of pubic symphysis (Therefore not a type A, at least a type B) Rami # Widening of right SIJ CT Bilateral partial posterior arch disruption Opening of right SIJ anteriorly Posterior right SIJ hinging Opening of left SIJ anteriorly Rotationally unstable but Vertically stable 61B3 Source: up to date Courtesy of Jim Fiechtl, MD

X-ray CT Type B, arguably Type C Tricky one! Pubic symphysis intact No vertical shear (Probably a type B) CT Complete posterior disruption Currently vertically stable (Type B) but has the potential to become vertically unstable (Type C) because of the complete posterior arch disruption Type B, arguably Type C

61C1 UNSTABLE Schematic X-ray CT Huge pubic symphysis disruption Schematic representation of Pubic Symphysis disruption Posterior arch disruption X-ray Huge pubic symphysis disruption (Therefore not a type A, at least a type B) 61C1 CT Complete disruption of posterior arch (Therefore, type C) Unilateral (Therefore, C1) UNSTABLE Source: up to date

61 C1 UNSTABLE Schematic X-ray CT reconstruction Pelvic Vertical Shear Schematic representation of Pubic Symphysis disruption Posterior arch disruption X-ray Pelvic Vertical Shear 61 C1 CT reconstruction Unilateral complete disruption of posterior arch UNSTABLE Source: up to date

61 C2 X-ray CT UNSTABLE Widening of pubic symphysis (Therefore not a type A, at least a type B) UNSTABLE 61 C2 CT Complete posterior arch disruption (Therefore, type C) Ipsilateral complete Contralateral incomplete (arrow) (Therefore, C2) Source: up to date

X-ray Pelvic Type C UNSTABLE Acetabular Type B1 Vertical Shear injury Right Rami # Left Sacral # Left Transverse Acetabular # Vertical Shear Pelvic Type C Transverse Acetabular # Acetabular Type B1 Need to know UNSTABLE Main Fracture is the Type C Pelvic Ring # because of it implications. It is associated with a left transverse acetabular # NB: need CT scans to provide more information about the #s Source: up to date Courtesy of Jim Fiechtl, MD

The end

Thank you for your attention, good luck with the test.