Part 2 of a lecture about acetabular fractures by Muhammad Abdelghani

1. Acetabular FracturesAcetabular Fractures
TreatmentTreatment
Muhammad Abdelghani

2. Goal of Treatment
 The goal of treatment is anatomic
restoration of the articular surface to
prevent posttraumatic arthritis.

3. Initial Management
The patient is usually placed in skeletal traction
to
1. allow for initial soft tissue healing,
2. allow associated injuries to be addressed,
3. maintain limb length, &
4. maintain femoral head reduction within the
acetabulum.

4. Non-operative treatment
Indications:
 Displacement <5mm in the dome, or articular step-off of
<2mm (with maintanance of femoral head congruency out of
traction, & absence of intraarticular osseous fragments).
N.B. If a fracture is displaced <2mm, no matter what the
anatomical type, nonoperative treatment should yield good
results.
 Distal anterior column or transverse (infratectal) fractures in
which femoral head congruency is maintained by the
remaining medial buttress.
 Maintenance of medial, anterior and posterior roof arcs >45°
(indicating fracture stability).

5. Roof arcs
 The medial, anterior, & posterior roof arcs are
measured on AP, obturator oblique, and iliac
oblique views, respectively.
 The roof arc is formed by the angle between
two lines, one drawn vertically through the
geometric center of the acetabulum, the other
from the fracture line to the geometric center.
 Roof arc angles are of limited utility for
evaluation of both column fractures and
posterior wall fractures.

6. Roof Arc Angles
 1. Medial Roof Arc (AP
pelvis)
 2. Anterior Roof Arc
(Obturator oblique)
 3. Posterior Roof Arc
(Iliac oblique)

7. Roof arc measurement

8. Operative treatment
Indications
 Head unstable and/or incongruous
 Guidelines to be correlated to patient factors.

9. Instability
 Hip dislocation associated with:
 Posterior wall or column fractures (posterior
instability)
 Major anterior wall fractures (anterior instability)
 Any fracture with significant size quadrilateral plate
fracture (Central instability)

10. Incongruity
 Alteration or inconsistency in relationship
between femoral head & acetabulum.
 Incongruity of the hip may result in early
degenerative changes & posttraumatic
osteoarthritis.
 Evaluation:
 Roof arc angle of Matta
 Roof arc measurement by CT.

11. 

12. Incongruity
 Displaced dome fractures:
 surgery is usually necessary to restore the weight-bearing surface.
 High transverse or T-type fractures
 These are shearing injuries that are grossly unstable when they involve the superior,
weight-bearing dome.
 Displaced both-column fractures (floating acetabulum): Surgery is indicated for
restoration of congruence if the roof fragment is displaced and secondary
congruence cannot be obtained or if the posterior column is grossly displaced.
 Retained osseous fragments may result in incongruity or an inability to maintain
concentric reduction of the femoral head..
 Femoral head fractures generally require ORIF to maintain sphericity and
congruity.
 Soft tissue interposition may necessitate operative removal of the interposed
tissues.
 Fractures through the roof or dome

13. Assessment of reduction
Assessment of reduction includes:
 Restoration of pelvic lines.
 Concentric reduction on all 3 views.
 The goal of anatomic reduction.

14. Operative treatment
Contraindications
Operative contraindications
 local or systemic infection,
 severe osteoporosis
Relative contraindications
 advanced age,
 associated medical conditions
 associated soft tissue and visceral injuries,
 multiply injured patient not stable for a big
acetabular surgery

15. Operative treatment
Timing
 Surgery should be performed within 2 weeks
of injury.
 It requires
 A well-resuscitated patient.
 Appropriate radiologic workup.
 Appropriate understanding of the fracture
pattern.
 Appropriate operative team.

16. Operative treatment
Timing
 Surgical emergencies include:
 Open acetabular fracture.
 New-onset sciatic nerve palsy after closed
reduction of hip dislocation.
 Irreducible posterior hip dislocation.
 Medial dislocation of femoral head against
cancellous bone surface of intact ilium.

17. Morel–Lavallé lesion
(Skin Degloving Injury(
 A closed degloving injury over the greater trochanter.
 Results from the blunt trauma that caused the fracture.
 The subcutaneous tissue is torn away from the underlying
fascia, and a significant cavity results
 Cavity contains hematoma and liquified fat.
 These areas must be drained and debrided before or during
definitive fracture surgery to decrease the chance of infection.
 Advisable to leave this area open through the surgical incision
or a separate incision.
 Dressing changes and wound packing are sometimes needed
for a prolonged period of time.
 Primary excision of the necrotic fat and closure over a drain
has not been routinely successful.

18. Surgical Approaches
 Kocher-Langenbeck (Posterior): best access to posterior column
(prone)
 ilioinguinal (Anterior): best access to anterior column and inner aspect
of innominate bone (supine)
 Extended iliofemoral (Lateral): best simultaneous access to the two
columns (lateral)
Combined approaches performed concurrently or
successively is less desirable
No single approach provides ideal exposure of all fracture types.
Proper preoperative classification of the fracture configuration is
essential to selecting the best surgical approach.

19. Kocher-Langenbeck Approach

20. Kocher-Langenbeck Approach
Anatomische Skizze der
Weichteilstrukturen bei
Kocher-Langenbeck-
Zugang
1 M. glutaeus maximus
2 M. glutaeus medius
3 M. glutaeus minimus
4 M. piriformis
5 M. gemellus
Superior
6 M. obturatorius internus
7 M. gemellus inferior
8 M. quadratus femoris
9 Lig. Sacrotuberale
10, N.,A.,V., glutea
inferior
11 N.,A.,V., glutea
superior

21. Kocher-Langenbeck Approach
Indications
 Posterior wall fractures
 Posterior column fractures
 Posterior column/posterior wall
fractures
 Juxtatectal/infratectal transverse or
transverse with posterior wall fractures
 Some T-type fractures

22. Areas accessible by Kocher-
Langenbeck approach
• Entire posterior
column
•Greater & lesser
sciatic notches
•Ischial spine
•Retroacetabular
surface
•Ischial
tuberosity
•Ischiopubic
ramus

23. The room is set up such that the x-rays and CT scans are
available for viewing during the procedure. The patient is
prone on a radiolucent table with SCD’s in place.

24. The affected extremity is positioned with a distal femoral
pin to allow for traction on the table with the hip in slight
extension and the knee flexed to relax the sciatic nerve.

25. The incision is midline over the femur, and angles
posteriorly at the posterior aspect of the greater trochanter
to end slightly superior to the posterior iliac spine.

26. The incision is midline over the femur, and angles posteriorly at the
posterior aspect of the greater trochanter to end slightly superior to
the posterior iliac spine.
GREATER
TROCHANTER

27. The skin incision is brought down to the level of the tensor
fascia lata, which is divided in line with the incision. The
gluteus maximus fascia is then divided.
GLUTEUS FASCIA
TENSOR
FASCIA
LATA

28. The gluteus maximus muscle is identified.
GLUTEUS MAXIMUS

29. The maximus muscle is gently separated digitally until
the first traversing branches of the nerve are visible.

31. GLUTEAL NERVE BRANCH
Dividing the gluteus maximus too far proximally
will denervate a significant portion of it.

32. GLUTEUS MAXIMUS
TROCHANTERIC BURSA
The trochanteric bursa is divided.

34. QUADRATUS
FEMORIS
View of the deep musculature with the Charnley retractor in place.
VASTUS LATERALIS
GLUTEUS
MEDIUS
SHORT EXTERNAL
ROTATORS

35. With gentle retraction anteriorly of the gluteus
medius, the piriformis tendon comes into view.
PIRIFORMIS
GLUTEUS
MEDIUS

36. OBTURATOR INTERNIS PIRIFORMIS
After minimal dissection along the posterior aspect of the
short external rotators the obturator internis tendon is identified
between the gamelli.

37. TAG SUTURES
Both the piriformis and obturator internis are tagged and resected
approximately 1cm away from their insertion in the femur. It is helpful
before this is performed to identify the sciatic nerve in an area of healthy
tissue, usually at the level of the quadratus femorus.

38. The piriformis and obturator internis are
being gently elevated using the sutures.
OBTURATOR
INTERNIS
PIRIFORMIS

39. With the piriformis being held back digitally, the sciatic nerve
is visualized running posterior to the obturator internis tendon.
OBTURATOR
INTERNIS
SCIATIC NERVE

40. Knowing that the nerve is safe and can be protected by the
obturator internis muscle, a Letournel retractor, or blunt
cobra, is placed anteriorly to the obturator internus tendon
into the lesser sciatic notch.

41. Knowing that the nerve is safe and can be protected by the
obturator internis muscle, a Letournel retractor, or blunt
cobra, is placed anteriorly to the obturator internus tendon
into the lesser sciatic notch.
BLUNT COBRA
RETRACTOR
OBTURATOR INTERNIS
SCIATIC
NERVE

42. Once in the lesser sciatic notch, posterior leverage on the retractor
allows exposure of the posterior aspect of the acetabulum while
protecting the nerve.
BLUNT COBRA
RETRACTOR
OBTURATOR INTERNIS
SCIATIC
NERVE

43. POSTERIOR ACETABULUM

44. FEMORAL
HEAD
DISPLACED POSTERIOR WALL
The femoral head and displaced portion
of the posterior wall are easily identified.

45. After the fracture and fracture bed are cleaned, the posterior
wall is reduced and fixed in place with a buttress plate.

46. After the fracture and fracture bed are cleaned, the posterior
wall is reduced and fixed in place with a buttress plate.
REDUCED FRACTURE

47. Ilioinguinal approach

48. Ilioinguinal Approach
Weichteilstrukturen bei
ilioinguinalem Zugang
1 M. psoas major
2 M. iliacus
3 Pecten ossis pubis
4 A. iliaca communis
5 A. iliaca interna
6 A. iliaca externa
7 Aa. Vv. Testiculares
8 V. iliaca communis
9 V. iliaca externa
10 N. ilioinguinalis
11 N. genitofemoralis
12 N. obturatorius
13 N. femoralis
14 N. cutaneus femoris lateralis
15 Ductus spermaticus
16 Ductus deferens

49. Ilioinguinal Approach
Indications
 Anterior wall
 Anterior column
 Transverse with significant anterior
displacement
 Anterior column/posterior hemitransverse
 Both-column

50. Setup: The patient is supine on a radiolucent
table with skeletal traction holding the affected
extremity in slight flexion. A perineal post is used
to allow for traction if needed.

51. Figure 6 Figure 7

52. ASIS
SYMPHYSIS
ASIS
A
The incision is drawn out. Figure A shows the location of the incision with
respect to the symphysis and ASIS. Figure B shows the patient from the
side as one would observe during surgery. The incision is curvilinear
towards the posterior aspect of the ilium. The surgery begins by
approaching the iliac crest along the area shown in figure B.
B

53. ASIS
SYMPHYSIS
ASIS
Figure 6 Figure 7
The incision is drawn out. Figure A shows the location of the incision with
respect to the symphysis and ASIS. Figure B shows the patient from the
side as one would observe during surgery. The incision is curvilinear
towards the posterior aspect of the ilium. The surgery begins by
approaching the iliac crest along the area shown in figure B.

54. Sharp retractors are used to identify the interval
between the abductor and abdominal musculature.

55. The iliac crest is indicated by purple lines. The interval between the
abdominal and abductor musculature occurs towards the posterior
aspect of the iliac crest as the abdominal musculature hangs over
the crest (dotted line)

56. The interval is taken with a Bovie down to the iliac crest
and the abdominal musculature is reflected anteriorly.

57. Closeup of previous image.

58. After the iliacus is released from the inside of the ilium a
large key elevator is used to elevate subperiosteally to
the SI joint.
ILIUM
ILIACUS

59. After this dissection is complete, the posterior aspect of the
iliac fossa is packed off with a lap and attention to brought
to the anterior portion of the incision.

60. Gelpi retractors are used to retract the skin and soft
tissue after the external oblique fascia is identified.
EXTERNAL OBLIQUE
FASCIA

61. The external oblique fascia is divided in line with
the incision and the fascia is reflected distally.
EXTERNAL
OBLIQUE
FASCIA

63. VAS DEFERENS, SPERMATIC
CORD, + ILIOINGUINAL NERVE
EXTERNAL
OBLIQUE
FASCIA
INGUINAL LIGAMENT
EXTERNAL
OBLIQUE
FASCIA
After this is performed, the vas deferens, spermatic cord, and ilioinguinal
nerve are identified and protected with a Penrose drain. Allis clamps are
used to retract the the external oblique fascia.

64. VAS DEFERENS SPERMATIC
CORD ILIOINGUINAL NERVE
EXTERNAL
OBLIQUE
FASCIA
INGUINAL LIGAMENT
EXTERNAL
OBLIQUE
FASCIA
It is helpful to include some subcutaneous tissue in the clamps to
protect the external oblique fascia from tearing. This exposes the
inguinal ligament, which is a reflection of the external oblique fascia.

65. An incision is made in the inguinal ligament, allowing
1 to 2mm of the ligament to reflect medially with the
musculature (dotted line).

66. Incision through the inguinal ligament.

68. ASIS
LATERAL FEMORAL
CUTANEOUS NERVE

69. ASIS
LATERAL FEMORAL
CUTANEOUS NERVE
As the dissection extends toward the ASIS, one needs
to identify the lateral femoral cutaneous nerve, which is
immediately under the inguinal ligament.

70. ASIS
LATERAL FEMORAL
CUTANEOUS NERVE
The nerve is typically located approximately 1cm medial
to the ASIS but is variable and may be more than one branch.

72. ASIS
PSOAS FEMORAL
NERVE
ILIOPECTINEAL
FASCIA
EXTERNAL
ILIAC
VESSELS

73. ASIS
PSOAS FEMORAL
NERVE
ILIOPECTINEAL
FASCIA
EXTERNAL
ILIAC
VESSELS
At this point, the identification of the iliopectineal fascia is performed,
allowing for retraction of the exteral iliac vessels and lymphatics medially.

74. ASIS
PSOAS FEMORAL
NERVE
ILIOPECTINEAL
FASCIA
EXTERNAL
ILIAC
VESSELS
The psoas muscle and femoral nerve are retractedlaterally. The army-
navy retractor protects the vasculature while the Allis clamp is holding
the iliopectineal fascia.

76. TRUE PELVIS
ILIOPSOAS
MUSCLE
FEMORAL NERVE
ILIOPECTINEAL
FASCIA
Closeup of previous image.

77. PSOAS FEMORAL NERVE
Closeup of the iliopectineal fascia demonstrating the psoas and femoral
nerve on the lateral side of the fascia in the false pelvis. The true pelvis
is located medial to the iliopecineal fascia over the pelvic brim.

78. PSOAS FEMORAL NERVE
Once the iliopectineal fascia is excised, access to the true pelvis is
obtained. The medial window of the approach is utilized when buttress
plating to the symphyseal body or symphyseal fixation is necessary.

79. PSOAS FEMORAL NERVE
In this case, the reduction and fixation was
performed through only the lateral and middle
windows.

81. LATERAL FEMORAL
CUTANEOUS NERVE
ILIAC FRACTURE
View from the opposite side of the table demonstrating
the lateral window and iliac wing fracture.

83. PSOAS
LATERAL FEMORAL
CUTANEOUS NERVE
VESSELS
PELVIC BRIM
View of the middle window demonstrating the pelvic brim.

84. PSOAS
LATERAL FEMORAL
CUTANEOUS NERVE
VESSELS
PELVIC BRIM
View of the middle window demonstrating the pelvic brim.

85. The following sequence will demonstrate the
view from the surgeon’s side of the table.

87. SI JOINT
ILIOPSOAS
This figure demonstrates the lateral window and exposure of
the anterior column from the iliac crest and SI joint proximally
to the psoas gutter and pelvic brim distally.

89. PELVIC
BRIM
PSOAS
VESSELS
This figure demonstrates the pelvic brim and displacement
of the fracture as seen through the middle window.

90. PELVIC
BRIM
PSOAS
VESSELS
This figure demonstrates the pelvic brim and displacement
of the fracture as seen through the middle window.

92. SUPERIOR RAMUS
FRAGMENT
DISPLACED ANTERIOR
COLUMN
Closeup of the fracture.

93. SUPERIOR RAMUS
FRAGMENT
DISPLACED ANTERIOR
COLUMN
Closeup of the fracture.

94. Extended iliofemoral approach

95. Extended Iliofemoral Approach
Operationssitus bei
erweitertem iliofemoralen
Zugang
1 M. gemellus superior
2 M. obturatorius internus
3 M. gemellus inferior
4 M. piriformis
5 M. quadratus femoris
6 Sehne des M. obturatorius
externus
7 Tuber ischiadicum
8 A. circumflexa femoris
medialis, tiefer Abzweig
9 N. ischiadicus

96. Extended iliofemoral approach
Indications
 Transtectal transverse + posterior wall or T-
shaped fractures
 Transverse fractures with extended posterior
wall
 T-shaped fractures with wide separations of
the vertical stem of the ‘T’ or those with‌
associated pubic symphysis dislocations
 Certain associated both column fractures
 Associated fracture patterns or transverse
fractures operated on >21 days following injury

97. Extended iliofemoral approach
Extended iliofemoral approach has the
highest incidence of ectopic bone
formation (HO) and longest
postoperative recovery

98. Other approaches
 Stoppa approach (supine): Allows
access to the medial wall of
acetabulum, quadrilateral surface, &
sacroiliac joint
 Triradiate approach (prone): Alternate
exposure to the external aspect of
innominate bone, with almost same
exposure as iliofemoral but visualization
of the posterior part of ilium is not as
good

99. Reduction Techniques
Special instruments.
 Essential instruments include pointed fracture
forceps, reduction clamps, fracture pushers,
and other standard fracture clamps.
 Special pelvic reduction clamps are extremely
helpful. The pelvic reduction clamp is screwed
directly to the bone using two 4.5-mm cortical
screws or 6.5-mm cancellous screws. This
clamp can be extremely helpful by applying
direct forces to the fracture.

101. Reduction Techniques
Traction.
 Traction on the femoral head is essential in
obtaining a reduction.
 Traction may be obtained by the use of a
traction table, which must be adaptable,
allowing the prone as well as the supine
position.
 An unscrubbed surgeon or technician is needed
to control the leg rotation.

102. Helpful Hints for Reduction
 The articular surface of the joint must
be adequately visualized by a wide
capsulorrhaphy in most cases.

103. Helpful Hints for Reduction
 Most patients can be managed
without a traction table, but direct
traction on the femoral head is
essential. This can be obtained by:
 a corkscrew in the femoral neck to
allow better retraction of the femoral
head and visualization of the articular
surface.
 A sharp hook over the greater
tuberosity can give the same effect.

104. Helpful Hints for Reduction
 A 5- or 6-mm Schantz pin with
a T-handle should be inserted
into the ischial tuberosity in
high transverse or T-type
fractures to allow rotation of
the posterior column, which in
some instances cannot be
reduced by any other method.

105. Helpful Hints for Reduction
 Holes should be drilled to accept the pointed
forceps.

106. Helpful Hints for Reduction
 Washers with
extensions have been
developed for use with
the pointed forceps.

107. Helpful Hints for Reduction
 Work within the fracture.
 In visualizing impacted fragments from either an
anterior or posterior approach, it is important to
move the major fracture out of the way so that the
impacted fragment can be visualized.
 This is akin to the tibial plateau fracture where the
lateral fragment is retracted like a book to allow
reduction of the impacted fragment.
 Therefore, work within the fracture where
possible.
 Marginally impacted fractures must be reduced in
this way.

108. Cerclage wires
 Cerclage wires inserted through the greater sciatic notch
and around the anterior inferior iliac spine may greatly
facilitate derotation & reduction of the columns, esp. if
either the posterior or anterior column is “high” on the
greater sciatic notch

109. Implants
Screws
– 6.5-mm cancellous lag screws
– 4.0-mm cancellous lag screws and 3.5 mm cortical screws
(lengths up to 120 mm)
– 6.5-mm fully threaded cancellous screws
 For fixation of the plate to bone, fully threaded cancellous
screws are desirable, the 6.5-mm screw for the large
reconstruction plate (4.5-mm) and the 3.5-screw for the
3.5-mm reconstruction plate.
 Cannulated screws may also be helpful.

110. Implants
Plates
 A 3.5-mm reconstruction plate is the implant of choice for acetabular
reconstruction.
 These plates can be molded in two planes and around the difficult areas
such as the ischial tuberosity.
 Also, precurved 3.5-mm plates are available for anterior column fixation.
 These plates are fixed with the 3.5-mm cancellous screws.
 In large individuals, and in pelvic fixation, the 4.5-mm reconstruction
plates are also useful, with fixation by the 6.5-mm fully threaded
cancellous screws; however, they are rarely used at this time.
The 3.5-mm and 4.5 mm
reconstruction plates for pelvic
fixation

111. Plates
Sites of Application
 The plates may be applied to the anterior column
from the inner table of the ilium to the symphysis
pubis.
 Plates may also be applied to the posterior column
and the superior aspect of the acetabulum.
 The distal screw should be anchored in the ischial
tuberosity.
 Great care should be taken to ensure that screws in
the central portion of the plate do not penetrate the
articular cartilage of the acetabulum.
 In most instances, no screws should be put into
that danger area, but if screws are necessary for
stable fixation, they should be directed away from
the joint. Screws within the joint are a not
uncommon cause of chondrolysis.
 Plates may be nested to buttress small fragments.

112. Internal fixation
 Stable fixation is best achieved by interfragmental
compression using lag screws.
 After provisional fixation of all fractures with K-wires,
or cerclage wires, screw fixation of the fractures is
essential. The joint must be visualized at all times to
ensure that anatomical reduction has been achieved
and that no screw penetrates the articular cartilage.
 After fixation by interfragmental lag screws, plates may
be used to neutralize the fracture.
 Plates may be placed either on the anterior or posterior
column, depending on the approach.

113. Internal fixation
 Adequate contouring of the plates is essential.
Otherwise, displacement of the opposite column
may occur.

114. Postoperative Care
 Indomethacin or irradiation: for heterotopic ossification
prophylaxis.
 A variety of treatments has been proposed to decrease the amount of
heterotopic bone including the use of diphosphonates, radiation and
indomethacin.
 Diphosphonates prevent the mineralisation of osteoid, but this begins again
after withdrawal of the drug, and their use has been questioned.
 There have been several reports of the use of indomethacin after operation for
acetabular fractures.
 Local radiation therapy has also been used after reports of successful results in
hip arthroplasty.
 Chemical prophylaxis, sequential compression devices, and
compressive stockings for thromboembolic prophylaxis.
 Mobilization out of bed is indicated as associated injuries allow.
 Full weight bearing on the affected extremity should be withheld
until radiographic signs of union are present (generally by 8-12 weeks
postoperatively).

115. Complications
 Surgical wound infection: Risk is increased secondary to the presence of
associated abdominal and pelvic visceral injuries.
 Nerve injury
 Sciatic nerve: Kocher-Langenbach approach with prolonged or forceful traction.
 Femoral nerve: Ilioinguinal approach may result in traction injury to femoral nerve. Rarely, the
nerve may be lacerated by an anterior column fracture.
 Superior gluteal nerve: most vulnerable in the greater sciatic notch. Injury during trauma or
surgery may result in paralysis of hip abductors with severe disability.
 Heterotopic ossification: Incidence is highest with extended iliofemoral
approach and second highest with Kocher-Langenbach. The highest risk is
a young male patient undergoing a posterolateral extensile approach in
which muscle is removed.
 Avascular necrosis: This devastating complication occurs mostly with
posterior types associated with high-energy injuries.
 Chondrolysis: This may occur with or without surgical intervention,
resulting in posttraumatic osteoarthritis. Concentric reduction with
restoration of articular congruity may minimize this complication.
 Thromboembolic complications

116. Case Study

117. Case Study
 An 18-year-old woman was
inadvertently struck on the lateral
aspect of the hip by a police officer
while marching in a homecoming
parade.

118. Case Study
Obturator
oblique
view
Iliac
oblique
view
AP, obturator oblique, and iliac oblique views show a both-column
acetabular fracture
The obturator oblique view shows the pathognomonic "spur-sign." Note that the spur represents
the iliac wing fragment, or the constant fragment, and the entire acetabulum has been
medialized.
None of the dome of the acetabulum remains attached to the iliac wing.

119. Case Study
Two- and three-dimensional CT scans show an ipsilateral
disruption of sacroiliac joint and extreme comminution through
the dome of the acetabulum.

120. Case Study
Two- and three-dimensional CT scans show an ipsilateral
disruption of sacroiliac joint and extreme comminution through
the dome of the acetabulum.
This patient also had disruption of the pubic symphysis, creating an
ipsilateral unstable hemipelvis with a both-column acetabular fracture.

121. Case Study
Final Reconstruction

122. Case Study
 Postoperative radiographs showing anatomic
reduction of the hemipelvis along with anatomic
reduction of the acetabular fracture.
 In high-energy trauma injuries such as this,
stability of the hemipelvis must be obtained first, by
stabilizing the anterior and posterior aspects of the
pelvis, after which the acetabular fracture is
addressed.
 Anatomic alignment of the pelvic inlet and outlet
should also be regained before the articular
component of the injury (acetabular fracture) is
addressed.

123. MCQ 1
 Which two quadrants of the acetabulum are most at
risk for injury by screws during fixation of total hip
arthroplasty (THA):
a) Anterior-inferior and posterior-superior
b) Anterior-superior and posterior-superior
c) Anterior-superior and anterior-inferior
d) Anterior-superior and posterior-inferior
e) Posterior-superior and posterior inferior

124. Answer 1
 Which two quadrants of the acetabulum are most at
risk for injury by screws during fixation of total hip
arthroplasty (THA):
a) Anterior-inferior and posterior-superior
b) Anterior-superior and posterior-superior
c) Anterior-superior and anterior-inferior
d) Anterior-superior and posterior-inferior
e) Posterior-superior and posterior inferior

125. Explanation
 The acetabular quadrant system described by Wasielewski and
colleagues is useful for determining the location of planned
acetabular screw fixation in THA to avoid neurovascular
complications. The quadrants are formed by drawing a line from the
anterior-superior iliac spine through the center of the acetabulum and
bisecting that line at the center of the acetabulum to form four equal
quadrants. The line from the anterior-superior iliac spine to the center
of the acetabulum serves as the dividing line between anterior and
posterior, and the bisecting line as the division between superior and
inferior.
In cadaver studies, the posterior-superior and posterior-inferior
quadrants were shown to have the thickest bone and best potential
for obtaining secure fixation with the least risk for injury to vessels.
The anterior-superior quadrant (the quadrant of death) and the
anterior-inferior quadrant were shown to be the most dangerous
quadrants for fixation due to the thin bone and close proximity of the
vessels to bone in that region.

126. MCQ 2
 Criteria for nonoperative management of an
acetabular fracture includes all of the following except:
a) Stability demonstrated by dynamic stress radiographs
b) Femoral head subluxation of 3 mm
c) Congruence of the femoral head with the unaffected
acetabular roof on the anteroposterior and Judet views
d) Roof arc measurement of greater than or equal to 45°
e) Unbroken computerized tomography arc at 10 mm from
subchondral bone

127. Answer 2
 Criteria for nonoperative management of an
acetabular fracture includes all of the following except:
a) Stability demonstrated by dynamic stress radiographs
b) Femoral head subluxation of 3 mm
c) Congruence of the femoral head with the unaffected
acetabular roof on the anteroposterior and Judet views
d) Roof arc measurement of greater than or equal to 45°
e) Unbroken computerized tomography arc at 10 mm from
subchondral bone

128. Explanation
 The outcome of nonoperative treatment of acetabular
fractures depends on the stability of the hip, the
concentricity of the head of the femur under the roof
of the acetabulum, and the condition of the roof itself.
 Nonoperative criteria include roof arc measurement of
at least 45°, unbroken subchondral computerized
tomography arc of 10 mm, stability of the joint on
stress radiographs, and congruence off the femoral
head with the unaffected acetabular roof on all three
views, anteroposterior and both Judet radiographs.
 Any subluxation reduces the likelihood of a good
result.

129. References
 Jimenez ML:
Classification of Acetabular Fractures.
Medscape.com
 Moore KD, Goss K, Anglen JO: Indomethacin
versus radiation therapy for prophylaxis against
heterotopic ossification in acetabular fractures.
J Bone Joint Surg [Br] 1998;80-B:259-63.
 Rommens PM, Hessmann MH:
Azetabulumfrakturen. Unfallchirurg 1999; 102:
591-610