Acetabulum Set 5 p 81

8/2/2019 Acetabulum Set 5 p 81

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FRACTURE OF ACETABULUM

The acetabulum can be described as an incomplete hemispherical socket with

an inverted horseshoe-shaped articular surface surrounding the

nonarticular cotyloid fossa.

This articular socket is composed of and supported by two columns of bone,

described by Letournel and Judet as an inverted Y.

The anterior column is composed of the bone of the iliac crest, the iliac

spines, the anterior half of the acetabulum, and the pubis.

The posterior column is the ischium, the ischial spine, the posterior half of

the acetabulum, and the dense bone forming the sciatic notch.

The column concept is used in classification of these fractures and is central

to the discussion of fracture patterns, operative approaches, and internal fixation.

The dome, or roof, of the acetabulum is the weight bearing portion of the

articular surface that supports the femoral head

Anatomical restoration of the dome with concentric reduction of the

femoral head beneath this dome is the goal of both operative and nonoperative

treatment.

The quadrilateral surface is the flat plate of bone forming the lateral border

of the true pelvic cavity and thus lying adjacent to the medial wall of the

acetabulum.

The iliopectineal eminence is the prominence in the anterior column that lies

directly over the femoral head.

Both the quadrilateral surface and the iliopectineal eminence are thin and

adjacent to the femoral head, limiting the types of fixation that can be used

in these regions


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Two-column concept of Letournel used in classification of acetabularfractures

The neurovascular structures passing through the pelvis are at riskduring the

original injury and subsequent treatment, and the various surgical approaches are

designed around these structures.

The sciatic nerve exiting the greater sciatic notch inferior to the piriformis

muscle frequently is injured with posterior fracture-dislocations of the hip

and fractures with posterior displacement

The functioning of both the tibial and common peroneal components of the

sciatic nerve must be carefully documented in the emergency department and

after subsequent interventions


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The superior gluteal artery and nerve exit the greater sciatic notch at its

most superior aspect and can be tethered to the bone at this level by variable

fascial attachments.

Fractures that enter the superior portion of the greater sciatic notch can be

associated with significant hemorrhage, possibly requiring angiography withembolization of the superior gluteal artery.

Knowledge of the intrapelvic relationships of the lumbosacral trunk, common and

external iliac vessels, and inferior epigastric vessels as well as of the obturator

artery and nerve becomes crucial as retractors, reduction forceps, drills, and

screws are used.

One particularly noteworthy anatomical relationship is the occasional large

anastomosis between the external iliac artery or inferior epigastric artery

and the obturator artery known as the corona mortis

Failure to ligate this vascular connection during the ilioinguinal approach

can lead to significant hemorrhage that is difficult to control as the external iliac

vessels are mobilized.

RADIOGRAPHIC EVALUATION

The acetabulum is evaluated radiographically with an AP pelvic view as well as

with the 45-degree oblique views of the pelvis described by Judet and

Letournel, commonly calledJudet views.

In the iliac oblique view, the radiographic beam is roughly perpendicular to

the iliac wing.

In obturator oblique view, radiographic beam is roughly perpendicular to the

obturator foramen.

Inclusion of the opposite hip in the radiographic field on the anteroposterior

and Judet views is essential for evaluation of symmetrical contours that may


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have slight individual variations and to determine the width of the normal

articular cartilage in each view.

The medial clear space between the femoral head and the radiographic

teardrop in the injured and uninjured hips should be compared on the

anteroposterior view as an indication offemoral head subluxation.

Fractures that traverse the anterior columndisrupt the iliopectineal line,

whereas fractures that traverse the posterior column disrupt the ilioischial

line.

Landmarks of standard anteroposterior radiograph of hip.

1. Iliopectineal line beginning at greater sciatic notch of ilium and extending down

to pubic tubercle.

2. Ilioischial line formed by posterior four fifths of quadrilateral surface of ilium.

3. Radiographic teardrop composed laterally of most inferior and anterior portion

of acetabulum and medially of anterior flat part of quadrilateral surface of iliac

bone.

4. Roof ofacetabulum.

5. Edge ofanterior lip ofacetabulum.

6. Edge ofposterior lip of acetabulum.


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A, Obturator oblique view of hip. B, Iliac oblique view of

hip.

In the operating room, the three standard views can be obtained with

fluoroscopy.

The restoration of the radiographic landmarks is a guide to the adequacy offracture reduction.

The anatomical dome is a three-dimensional structure composed of

subchondral bone and its overlying cartilage that articulates with the weight

bearing portion of the femoral head.

Multiple studies have concluded that the single most important factor

affecting long-term outcome in both operatively and nonoperatively treated

acetabular fractures is maintenance of a concentric reduction of the

femoral head beneath an intact or anatomically reconstructed dome.

The dome, or roof, can be seen on the anteroposterior and Judet views of the

pelvis, but the subchondral bone shown on each of these views is only 2 to 3 mm

wide and represents only that small portion of the actual articular weight bearing

surface that is tangential to the x-ray beam.

Matta et al. developed a system for roughly quantifying the acetabular

dome after fracture, which they called the roof arc measurements.


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These measurements involve determination ofhow much of the roof remains

intact on each of the three standard radiographic views: anteroposterior,

obturator oblique, and iliac oblique.

The medial roof arc is measured on the anteroposterior view by drawing a

vertical line through the roof of the acetabulum to its geometric center.

A second line is then drawn through the point where the fracture line

intersects the roofof the acetabulum and again to the geometric center of

the acetabulum.

The angle thus formed represents the medial roof arc

The anterior and posterior roof arcs are similarly determined on the

obturator oblique and iliac oblique views, respectively

Although these are rough quantitations, they are useful in the assessment of

fractures of the posterior or anterior column, transverse fractures, T-type

fractures, and associated anterior column and posterior hemitransverse

fractures; they have limited usefulness for evaluation of both-column fractures

and fractures involving the posterior wall.

According to Matta et al., ifany of the roof arc measurements in a displaced

fracture are less than 45 degrees, operative treatment should be

considered.

Computed tomography is invaluable in the treatment of acetabular fractures.

Axial cuts must be taken with thin (3-mm) intervals and corresponding slice

thicknesses.

The entire pelvis generally is included to avoid missing a portion of the fracture,

and comparison to the opposite hip is performed routinely.

In general, the transverse fracture lines and fractures of the anterior and

posterior walls are in the sagittal plane, paralleling the quadrilateral surface

when they are viewed on axial CT images

Anterior and posterior column fractures usually extend through the

quadrilateral surface and into the obturator foramen with a more coronalorientation; variant fracture types, however, may not follow these generalities.

Olson and Matta showed that CT scans can give the same information about the

acetabular dome as the roof arc measurements on the anteroposterior and oblique

radiographs.


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Axial CT scans showing the superior 10 mm of the acetabular roof to be intact

corresponded to radiographic roof arc measurements of 45 degrees.

They also found that fracture of the cotyloid fossa did not jeopardize stability of

the femoral head under the dome if the fossa extended to within 10 mm of the

apex of the roof and the articular surface was intact.

Three-dimensional CT reconstructions of a fracture have become sophisticated

and can be projected in many different views with subtraction of the femoral head

that show unique features of the various fracture patterns..

CLASSIFICATION

The classification of acetabular fractures described by Letournel and Judet is the

most widely used classification system.

They divided acetabular fractures into two basic groups: simple fracture types

and the more complex associated fracture types.

Simple fracture types are isolated fractures ofone wall or column along

with transverse fractures; this type includes fractures of the:

1. Posterior Wall,

2. Posterior Column,

3. Anterior Wall, Or Anterior Column

4. Transverse Fractures.

The associated fracture types have more complex fracture geometries and

include:

1. T-Type Fractures,

2. Combined Fractures of the Posterior Column and Wall,

3. Combined Transverse and Posterior Wall Fractures,

4. Anterior Column Fractures with a Hemitransverse Posterior Fracture

5. Both-Column Fractures.


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Letournel and Judet classification of acetabular fractures.

A. Posterior wall fracture.

B. Posterior column fracture.

C. Anterior wall fracture.

D. Anterior column fracture.

E. Transverse fracture.

F. Posterior column and posterior wall fracture.

G. Transverse and posterior wall fracture.

H.T-shaped fracture.

I. Anterior column and posterior hemitransverse fracture.

J. Complete both-column fracture

Although several of the associated fracture types involve both columns of the

acetabulum, the designation both-column fracture in this classification denotes


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that none of the articular fracture fragments of the acetabulum maintain

bony continuity with the axial skeleton: a fracture line divides the ilium, so

the sacroiliac joint is not connected to any articular segment.

The spur sign, shown on the obturator oblique view, is pathognomonic of a both-

column fracture.

It represents the remaining portion of the ilium still attached to the sacrum and is

seen projected lateral to the medially displaced acetabulum

The AO group has developed an alphanumeric classification system for

acetabular fractures based on the severity of the fracture:

Type A fractures include fractures of a single wall or column;

Type B fractures involve both anterior and posterior columns (transverse, or T-

type, fractures);

Type C fractures involve both anterior and posterior columns, but all

articular segments, including the roof, are detached from the remaining

segment of intact ilium

Type C fractures are those designated both-column fractures in the Letournel and

Judet classification.

Each type has subtypes 1, 2, and 3 (e.g., A1, A2, or A3), depending on the

characteristics of the fracture.

TREATMENT

Initial Treatment


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Acetabular fractures generally are caused by high-energy trauma, and associated

injuries are frequent.

Treatment of the entire patient should follow accepted Advanced Trauma Life

Support (ATLS) protocol, with orthopaedic management of the acetabular

fracture appropriately integrated into the treatment plan.

In general, operative treatment of an acetabular fracture should not be

performed as an emergency except when it is part ofopen fracture

management or is performed for a fracture associated with an irreducible

dislocation of the hip.

In the latter case, urgent open reduction of the hip dislocation and treatment

of the associated fracture are required to prevent the complications of

osteonecrosis and ongoing cartilaginous damage to the femoral head.

Closed reduction of hip dislocations should be performed with sedation in theemergency department or with general anesthesia and fluoroscopy.

The patient then can be placed in skeletal traction to maintain reduction and

possibly slight distraction of the hip while the other acute injuries are treated and

radiographic studies of the pelvis are obtained.

The older term central fracture-dislocation of the hip was previously used to

describe any acetabular fracture with medial subluxation of the femoral

head.

Although this terminology has been replaced with more descriptive fracture

classification systems, a true central fracture-dislocation, with the femoral

head completely dislocated medially into the pelvis, is an unusual injury that

requires urgent treatment

The femoral head can be locked between the fracture fragments, making

reduction extremely difficult.

Closed reduction with general anesthesia and fluoroscopic assistance should be

attempted.

After reduction, the femoral head is extremely unstable and will easily redisplace

into the pelvis if skeletal traction is not maintained

INDICATIONS FOR NONOPERATIVE TREATMENT

1) Nondisplaced and Minimally Displaced Fractures


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Fractures that traverse the weight bearing dome but are displaced less

than 2 mm can be treated with nonweight bearing for 6 to 12 weeks,

depending on the fracture characteristics.

Radiographs should be obtained immediately after the patient is first mobilized

and periodically thereafter to ensure that no displacement has occurred.

2) Fractures with Significant Displacement but in which the region of the

joint involved is judged to be Unimportant Prognostically

This determination is made with the roof arc measurements described by Matta

and Olson as 45 degrees for each roof arc: medial, anterior, and posterior.

Most authors agree that displaced fractures through the weight bearing

dome should be treated with operative reduction and internal fixation,

regardless of how they may line up in traction.

These fractures have a tendency to displace, leading to inferior results.

One exception to this rule is an extremely comminuted both-column

fracture that attains secondary congruence.

In reality, very few fractures are treated definitively by traction to maintain a

reduction of the acetabular dome.

Posterior wall fractures associated with posterior fracture-dislocations of

the hip require separate consideration and are evaluated after closed reduction.

Larger posterior wall fragments lead to posterior hip instability andrequire fixation.

Posterior wall fractures involving more than 50% of the posterior wall consistently

led to posterior hip instability.

Traditionally, any patient for whom nonoperative treatment of a small

posterior wall fracture is being considered should have a clinical evaluation

of hip stability with flexion to 90 degrees with the patient sedated or

under general anesthesia.

We should perform stress views under fluoroscopy when patients are consideredfor nonoperative treatment of smaller posterior wall fractures.

As described by Tornetta, view the pelvis in the obturator oblique view,

flexing the hip to 90 degrees with enough posteriorly directed pressure to rock the

pelvis.


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Spot fluoroscopic views obtained during performance of this maneuver are

scrutinized to assess subluxation.

Stable hips are treated similar to pure dislocations of the hip, with

mobilization on crutches with range of motion restrictions and progressive weight

bearing during approximately 2 weeks.

3) Secondary Congruence in Displaced Both-Column Fractures

A both-column fracture, by definition, has all its fragmentsfree to move

independent of the remaining ilium.

Frequently, comminuted both-column fracture fragments assume a

position ofarticular secondary congruency around the femoral head,

even though the femoral head is displaced medially and there may be gaps

between the fracture fragments.

The concept ofsecondary congruence was described by Letournel, and

closed treatment of these fractures has yielded reasonable and occasionally

exceptional results.

The concept applies only to this specific subset of fractures and cannot be

applied to other fracture types.

4) Medical contraindications to surgery

In patients with multiple trauma, medical contraindications from multisystem

injury are common, even in previously healthy patients.

On occasion,severity of the medical condition mandates that operative

intervention be delayed.

On occasion, severe head trauma with a tenuous, evolving spectrum of injury

may preclude a surgical procedure.

5) Local Soft-Tissue Problems, such as Infection, Wounds, and Soft-Tissue

Lesions from Blunt Trauma

An open wound in the anticipated surgical field is a contraindication, as is

systemic infection.

The Morel-Lavalle lesion is a localized area of subcutaneous fat necrosis

over the lateral aspect of the hip caused by the same trauma that causes the

acetabular fracture.


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The size and extent of this lesion are variable, and operating through it has

been associated with a higher rate of postoperative infection.

Alternatively, some fractures can be treated through the ilioinguinal approach,

thus avoiding the affected area.

The presence of a significant Morel-Lavalle lesion can be suspected by

hypermobility of the skin and subcutaneous tissue in the affected area from

the shear-type separation of the subcutaneous tissue from the underlying

fascia lata.

The presence of a suprapubic catheter generally is considered a

contraindication to acetabular openreduction and internal fixation by the

ilioinguinal approach.

The best method of avoiding this situation is to discuss with the urologist the

possibility ofavoiding suprapubic drainage of the bladder with possibleprimary repair of the bladder rupture and Foley catheter drainage.

6) Elderly Patients with Osteoporotic Bone in Whom Open Reduction May

Not Be Feasible

Only rare comminuted fractures in elderly, osteopenic patients cannot be treated

by standard open reduction and internal fixation.

The options for these patients include mobilization without fixation,

percutaneous fixation with mobilization, and primary total hip

arthroplasty.

INDICATIONS FOR OPERATIVE TREATMENT

1) Fracture Characteristics

An acetabular fracture with 2 mm or more of displacement in the dome of the

acetabulum as defined by any roof arc measurementsof less than 45

degrees is an indication for operative intervention, as is any subluxation of

the femoral head from a displaced acetabular fracture noted on any of the

three standard radiographic views.

Also, operative treatment should be considered for posterior wall fractureswith more than 50% involvement of the articular surface

Posterior wall fractures involving less than 50% of the wall may be unstable

and are assessed clinically by flexing the hip to 90 degrees with the patient

sedated or anesthetized as well as by stress testing ofequivocal cases under

anesthesia with fluoroscopy.


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2) Incarcerated Fragments in the Acetabulum after Closed Reduction of a

Hip Dislocation

Fragments noted on CT scan to be lodged between the articular surfaces of the

femoral head and the acetabulum warrant excision.

3) Prevention of Nonunion and Retention of Sufficient Bone Stock for Later

Reconstructive Surgery

The last indication is debatable and should be applied only in cases of extreme

deformity because total hip arthroplasty after failed open reduction and internal

fixation of an acetabular fracture may be more difficult than hip arthroplasty after

nonoperative management.

Timing of Surgery

Most authors advocate waiting 2 or 3 days after injury before performing

acetabular surgery to allow the patient to be adequately stabilized and to allowpelvic bleeding to subside.

Ideally, operative reduction and internal fixation of acetabular fractures

should be performed within 5 to 7 days of injury.

Anatomical reduction becomes more difficult after that time because

hematoma organization, soft-tissue contracture, and subsequent early

callus formation hinder the process of fracture reduction, especially if the more

limited Kocher-Langenbeck or ilioinguinal exposure is used.

After a delay of more than 2 to 3 weeks, an extensile exposure may benecessary to obtain adequate reduction.

Choice of Surgical Approach

Some fracture patterns are routinely reduced through an anterior ilioinguinal

approach, whereas the posterior Kocher-Langenbeck approach is more

appropriate for others.

With transverse fractures, the choice of an anterior or posterior approach is

determined by which exposure allows access to the side of the fracture with

maximal displacement.

Osteotomy of the trochanter also can aid exposure oftransverse fractures

or supraacetabular extension of fractures of the posterior column and wall.

This osteotomy does not seem to affect the vascularity of the femoral head and

has a high rate of union.


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Siebenrock et al. described the trochanteric flip osteotomy, leaving the vastus

lateralis attached to the trochanteric fragment, similar to a trochanteric slide

osteotomy.

More complicated fractures may require one of the extensile approaches, such as

the extended iliofemoral approach described by Letournel and Judet, thetriradiate approach of Mears and Rubash, or the T-approach described by

Reinert et al.

If an extensile exposure is used, Bosse et al. recommended confirmation of the

patency of the superior gluteal artery with angiography because this may be the

only vascular pedicle supplying the abductor muscles.

Treatment of Specific Fracture Patterns


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A, Multifragmented posterior wall fracture with intraarticular comminution. B,

Posterior column fracture with lag screw reaching anterior column. C, Transverse

fracture with lag screw reaching anterior column. D, Associated transverse and

posterior wall fracture. E, Associated T-type acetabular fracture. Lag screws are

inserted into both anterior and posterior columns. F, Anterior column fracture.

Several lag screws are placed between inner and outer tables of innominate bone. G,

Associated anterior column and posterior hemitransverse fracture. Screws insertedfrom pelvic brim must reach distal to fracture line and engage in posterior column


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H, Both-column fracture operated on through ilioinguinal approach. Screws inserted

from pelvic brim reach posterior column. I, Both-column fracture. Internal fixation is

performed through extended iliofemoral approach. Two very long screws are inserted

into anterior column and reach superior pubic ramus

POSTERIOR WALL FRACTURES

The most common fracture treated by the average orthopaedist is the posterior

wall fracture.

These fractures are treated through a Kocher-Langenbeck approach with the

patient positioned either prone or in the lateral decubitus position on a

fracture table.

To avoid osteonecrosis of the posterior wall, the posterior wall fragments

must not be detached from the posterior capsule during exposure.

If the fracture extends superiorly into the dome, a trochanteric osteotomymay be performed to allow additional exposure.

The hip is distracted to clear any incarcerated fragments before reduction of

the wall fragments.

A close inspection is made for marginal impaction of articular fragments into

the intact posterior column.


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Impacted segments are elevated and bone grafted.

After reduction of the wall fragments, provisional fixation with Kirschner

wires can be used while definitive fixation is performed with lag screws and a

contoured reconstruction plate placed from the ischium, over the

retroacetabular surface onto the lateral ilium.

The use ofspring plates has been advocated to improve stability in comminuted

fractures.

These are made out ofone-third tubular plates by cutting or breaking the

plate through the last screw hole and bending down the remaining end as tines,

which are used to capture bone fragments that cannot be easily fixed with

screws.

The spring plate is slightly overcontoured so that when the reconstruction

plate is applied over the spring plate, the captured fragments are heldfirmly in position.

Osteonecrosis of the femoral head as a result of associated hip dislocation,

marginal impaction, multiple fracture fragments, and osteochondral injuries of the

femoral head all adversely affect the out-come of these fractures.

Intraarticular screw placement must be avoided & Intraoperative fluoroscopy in

multiple views should be used to ensure that all screws are extraarticular.

Posterior wall fracture fixed with contoured 3.5-mm pelvic reconstruction plate.

Posterior wall acetabular fracture treated with spring plate and associated contoured

pelvic reconstruction plate.

POSTERIOR COLUMN FRACTURES

Posterior column fractures are relatively uncommon and, if significantly

displaced, require operative reduction and internal fixation.

The Kocher-Langenbeck approach is used routinely.


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Rotational deformity in addition to displacement must be corrected by placement

of a Schanz screw in the ischium to control rotation while the fracture is

reduced with a reduction clamp.

Typical fixation is with a lag screw combined with a contoured

reconstruction plate along the posterior column.

Posterior column fracture of acetabulum

ANTERIOR WALL AND ANTERIOR COLUMN FRACTURES

Isolated anterior wall fractures are uncommon and sometimes associated with

anterior hip dislocation.

Fractures requiring surgery are fixed through an ilioinguinal or iliofemoral

approach.

Anterior column fractures are approached similarly, with fixation by a contoured

plate along the pelvic brim

At the level of the iliopectineal eminence, the medial wall of the acetabulum

is thin, and screws generally should not be placed in this region.

Anterior column fractures that exit higher through the iliac wing require

fixation along the iliac crest as well.


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Fixation of low anterior column fracture with contoured plate along pelvic brim.

TRANSVERSE FRACTURES

These fractures, although apparently simple, present a spectrum of

difficulty.

Transtectal fractures, or fractures that occur above the cotyloid fossa,

have the worst prognosis, and accurate reduction is essential.

Juxtatectal fractures, those that occur at thejunction of the cotyloid

fossa with the articular surface, also usually require reduction, whereasinfratectal fractures frequently can be treated nonoperatively.

Reduction most often is through a posterior approach with the patient

positioned prone.

A small Jungbluth clamp is used to reduce the fracture while rotation is

controlled by a Schanz screw in the ischium.

The intraarticular reduction can be assessed directly by distracting the limb in

traction and by palpating the reduction of the quadrilateral surface through

the greater sciatic notch.

Posterior fixation typically is with a buttress plate along the posterior

column with anterior fixation, by use of a 3.5-mm lag screw placed into the

anterior column from a position above the acetabulum.

Care must be taken with placement of the anterior lag screw because of the

proximity ofthe iliac vessels.


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From the ilioinguinal approach, reduction can be performed by a variety of

methods.

We frequently use plate reduction to close the fracture gap; a large

spiked reduction clamp placed on the quadrilateral surface and the lateral

surface of the ilium in the region of the anterior inferior spine controls medialdisplacement and rotation of the caudad fragment.

Typical fixation is a contoured plate along the pelvic brim with lag screws

directed down the posterior column

On occasion, extensile or combined approaches are necessary for more

complex transverse fractures

POSTERIOR COLUMN FRACTURE WITH ASSOCIATED POSTERIOR WALL

FRACTURE

A Kocher-Langenbeck approach is used, with or without a trochanteric osteotomy.

The column fracture is reduced first, and a short reconstruction plate is

placed posteriorly along the posterior edge of the column.

A separate plate is used for the wall fragment.

When the wall fragment is small, spring plates can be used instead of a

separate wall plate.

Posterior column and posterior wall acetabular fracture fixed with two plates. First

reconstructs posterior column, and second reconstruction plate (supplemental spring

plate) fixes posterior wall fragments

TRANSVERSE FRACTURE WITH ASSOCIATED POSTERIOR WALL FRACTURE


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This common fracture usually is treated through the Kocher-Langenbeck

approach with the patient prone.

The intraarticular portion of the transverse fracture can be seen through the

defect created by the retraction of the posterior wall fragment.

Reduction of the transverse fracture can be difficult through a Kocher-Langenbeck

approach, particularly when there is impaction of a portion of the dome

An extensile approach rarely may be preferable with comminution of the dome.

Typical fixation is performed by fixing the transverse component with lag

screws into the anterior column while plating the posterior wall, thus further

stabilizing the posterior portion of the transverse fracture.

Transverse posterior wall acetabular fracture fixed through Kocher-Langenbeck

approach with additional trochanteric osteotomy

T-TYPE FRACTURES

These fractures usually can be treated with the patient prone through a

Kocher-Langenbeck approach.

The anterior column fracture line can be reduced through the sciatic notch

after reduction of the posterior column portion or reduced first with displacement

of the posterior column, facilitating clamp placement.

The anterior column is fixed with screws placed down the anterior columnfrom a position above the acetabulum; the posterior column portion can be

fixed with a lag screw and a reconstruction plate.

These fractures can occasionally be treated through an ilioinguinal approach

with a contoured plate placed along the pelvic brim and lag screws

extending into the posterior column.


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Ifboth the anterior and posterior components of the fracture are

significantly displaced, extensile or combined approaches may be required to

obtain a reduction.

On occasion, with T-type fractures as well as other associated fracture types, a

separate medial fragment is present.

If it is proximal enough to affect stability, a spring plate bent at a 100- to

110-degree angle can be placed under an anterior column plate to maintain

reduction of this fragment.

Another method of fixing this fragment is to place a plate along the quadrilateral

surface through a split in the linea alba (Stoppa approach).

ANTERIOR COLUMNPOSTERIOR HEMITRANSVERSE FRACTURES

These fractures frequently have minimal displacement of the hemitransverse

component and can be treated through the ilioinguinal approach with typical

fixation of the anterior column fracture and separate lag screws from the iliac

fossa adjacent to the pelvic brim extending down the posterior column.

Fractures with significant posterior displacement or intraarticular

comminution with or without impaction may require combined or extensile

approaches.

BOTH-COLUMN FRACTURES

These fractures are sometimes described as T-type fractures that have their

transverse component above the dome of the acetabulum.

They have varying degrees of comminution and can be extremely complex

and difficult to treat.

Many both-column fractures can be treated through an anterior ilioinguinal

approach but a posterior or extensile exposure is required for involvement of

the sacroiliac joint, a significant posterior wall fracture, or intraarticular

comminution that requires reduction under direct vision.

In general, reduction is begun from the most proximal portion of the fracture and

proceeds toward the joint.

Each small fragment must be anatomically reduced because small malreductions

in the ilium above the fracture become magnified at the level of the joint.

Fixation is as varied as the fracture patterns and the approaches used.


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POSTOPERATIVE CARE

Postoperatively, closed suction drainage is used, antibiotic therapy is continued

for 48 to 72 hours, and passive motion of the hip is begun on the second or third

day.

Touch-down ambulation with crutches usually is allowed by the second to

fourth day and progresses gradually, depending on other injuries.

This minimal weight bearing status is continued for approximately 8 weeks in

patients with simple fractures and 12 weeks in most others.

COMPLICATIONS

1) Mortality - Overall mortality rates after acetabular fractures range from 0% to

2.5%.

2) Osteonecrosis - Itoccurs more frequently after fractures associated withposterior dislocation & is radiographically apparentwithin 2 years of

injury in most patients. Letournel's reported rate of osteonecrosis after

posterior dislocation was 7.5%. Osteonecrosis of the posterior wall can be

caused by the injury or by excessive fracture site exposure because the only

vascular supply of these fragments is the injured posterior capsule of the

hip.

3) Infection - Infections are reported to occur in 1% to 5% of patients and may

destroy the hip joint. Certain factors are thought to increase the risk of

infection, including the presence of a suprapubic catheter in ilioinguinal

approaches and the Morel-Lavalle lesion in Kocher-Langenbeckandextensile approaches. Obesity has been shown to increase the rate of multiple

complications including infection.

4) Sciatic nerve palsies as a result of the initial injury occur in approximately 10%

to 15% of patients with acetabular fractures.Sciatic nerve injury as a

result of surgery occurs in 2% to 6% of patients and is more often associated

with posterior fracture patterns treated through the Kocher-Langenbeck

and extensile exposures. The peroneal component of the sciatic nerve was

more often involved than the tibial component and that the tibial component

had a greater chance of recovery; complete peroneal palsies had the

worst prognosis. Functional recovery has been shown in approximately 65% of

patients, and function may improve up to 3 years after injury.

5) Heterotopic ossification occurs after most extensile approaches, with

moderate-to-severe heterotopic ossification occurring in 14% to 50% of patients

when no prophylaxis is used; it occurs after the Kocher-Langenbeck

approach in approximately 25% of patients in whom no prophylaxis is used


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.Heterotopic ossification is rare after the ilioinguinal approach unless the external

surface of the ilium is stripped. The effectiveness and choice of prophylactic

measures to prevent heterotopic ossification remain controversial. Currently, for

most patients treated with the Kocher-Langenbeck approach, use indomethacin

(25 mg three times a day for 4 to 6 weeks) or radiation therapy with a one-

time dose of 700 cGy in patients in whom indomethacin is contraindicated.

6) Thromboembolic complications can be devastating; the reported risk of

pulmonary embolism ranges from 2% to 6%. Deep vein thrombosis has been

reported to occur in 8% to 61% of patients with acetabular fractures. Current

protocol involves the use of subcutaneous heparin or enoxaparin as well as

intermittent compression boots while patients are awaiting surgery. Obtain a

preoperative screening duplex Doppler scan in any patient in whom the injury is

more than 4 days old. Use Greenfield vena cava filters in patients with

abnormalities on duplex scans and also occasionally use them in high-risk groups,

including patients older than 60 years, patients with contraindications to

anticoagulation, and patients in whom morbid obesity, malignant disease, or a

history of prior deep vein thrombosis is a factor. Postoperatively, anticoagulation

with enoxaparin followed by warfarin is continued for 6 to 12 weeks unless it is

medically contraindicated.

Total Hip Arthroplasty as Treatment for Acetabular Fracture

Acetabular fractures with extremely poor prognoses can be treated with

primary total hip arthroplasty, using adjunctive fixation of the acetabular

fracture with plates or cables and multiple screw fixation of the cup.

Examples include a neglected comminuted, incongruous, both-column fracture ,late presenting unreduced posterior fracture-dislocation of the hip with severe

marginal impaction and femoral head erosion

One concern with this technique is that the cementless acetabular component

could fail to be incorporated adequately in the healing acetabular bed.

Extensile approaches should be avoided to minimize the risk of infection

Acetabulum Set 5 p 81

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Transcript of Acetabulum Set 5 p 81