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Current Orthopaedics (2005) 19, 140–154

KEYWORDAcetabularfractures;ClassificatiAssessmenNon-operatreatmentOperativetreatmentSurgical apSurgical teComplicatiOutcome

0268-0890/$ - sdoi:10.1016/j.c

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E-mail addrjnpowellemail@

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TRAUMA

Acetabular fractures

J. McMaster�, J. Powell

Department of Surgery, University of Calgary, AC144C 1403-29th Street NW, Calgary, Alta., Canada

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ng author. Tel: +1 403 28004.esses: jmcmaster@doctyahoo.ca (J. Powell).

Summary The relative infrequency and complexity of acetabular fracturesprovide a challenge for trauma surgeons. In young patients, the management maybe complicated by other injuries. The aim of treatment is to maintain a stablecongruent joint. Although there is a role for non-operative treatment the hip jointtolerates instability and incongruity poorly. Operative treatment is complex due tothe limitations of the surgical approaches, and the complex three-dimensionalanatomy. The relative merit of each surgical option must be considered, and thedecision is often a compromise of exposure vs. complications. In the older patients,achieving a stable congruent hip, with open reduction and internal fixation, may notbe possible due to poor bone quality. Total hip replacement may be considered abetter option. Outcome of acetabular fractures is dependent on the quality ofsurgical reduction and fixation, in turn this has been related to the experience of thesurgeon.& 2005 Elsevier Ltd. All rights reserved.

Introduction

Treatment of fractures of the acetabulum is achallenge for orthopaedic surgeons for severalreasons:

�

There are two distinct groups that make up themajority of acetabular fracture patients.J High energy trauma in young active patients,

frequently associated with poly-trauma.J Older patients with poor bone stock who

frequently present with complex fracturepatterns.

Elsevier Ltd. All rights reserv

70 2015;

ors.org.uk (J. McMaster),

�

ed.

Irreversible damage to the articular surface.

� Comprehension of fracture patterns requires a

detailed understanding of complex three-dimen-sional pathoanatomy.

�

Difficult surgical access. � Prolonged rehabilitation. � Significant potential post-operative complica-

tions.

Anatomy and biomechanics

The acetabulum is formed by the ilium, pubis andischium and during development they are linkedtogether to form the triradiate cartilage. Thetriradiate cartilage has its apex in the floor of theacetabulum and fuses between 18 and 23 years ofage. For the purposes of fracture description the

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Acetabular fractures 141

nomenclature described by Letournel and Judet1 ismost commonly used. The anterior column (Fig. 1)includes the anterior iliac crest, anterior acetabu-lum and superior pubic ramus. The posteriorcolumn extends from the sciatic notch to theischial tuberosity and includes the posterior wallof the acetabulum. Fractures involving the anteriorand posterior columns characteristically passthrough relatively weak areas. The columns areattached to the sacrum through a strut of densebone called the sciatic buttress. This transmits loadbetween the torso (via the sacrum) and the lowerextremity (via the columns). The main weightbearing surface of the acetabulum is cradledbetween the anterior and posterior columns andis referred to as the dome or roof. Fractures mayalso involve the anterior and posterior walls of theacetabulum in isolation or in combination withcolumn fractures. The cortical bone overlying theacetabulum within the inner wall of the true pelvisis called the quadrilateral plate.

Key to the management of acetabular fractures isthe nerves and blood vessels that supply themuscles around the hip and the blood supply ofthe femoral head and acetabulum (Fig. 2). Thesuperior and inferior gluteal neurovascular bundlessupply the gluteus medius/minimus and gluteusmaximus, respectively. These structures can bedamaged at the time of injury or intraoperatively.The deep branch of the medial femoral circumflexartery (MFCA) is the primary blood supply to thefemoral head and must be protected to ensureviability of the femoral head. This vessel has aconstant extracapsular course2 that runs along theinferior border of obturator externus and thensuperiorly over the anterior surface of the inferior

Figure 1 Descript

gemellus, obturator internus and superior gemellusclose to their common femoral insertion. Terminalbranches then perforate the joint capsule, 2–4mmlateral to the bone cartilage junction, at the levelof the superior gemellus. An anastomosis betweenthe inferior gluteal artery and the deep branch ofthe MCFA runs along the inferior border of thepiriformis. The acetabulum and hemi-pelvis areabundantly supplied as a result of its muscularattachments. However, problems can arise whenthe soft tissue approach involves extensive strip-ping from both the inner and outer table of thepelvis.

Classification

Acetabular fractures are commonly classified usingthe Letournel–Judet system.1 This classificationsystem describes the fracture in terms of elemen-tary fractures and associated fractures (Fig. 3), andhas been assimilated into the AO comprehensiveclassification system.

A column fracture describes a fracture that hasseparated all or part of the column from the axialskeleton. T-shaped and transverse fractures involvefracture lines extending through the acetabularpart of both columns; however, the superior part ofthe columns remains in continuity with the axialskeleton. A T-shaped fracture differs from atransverse fracture as it also has an extensionwhich runs through the inferior part of theacetabulum and splits the rami. A both columnsfracture can be considered a ‘high’ T-shapedfracture where both columns have been separatedfrom the sciatic buttress.3 A fracture is described as

ive anatomy.1

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Figure 2 Nerve and blood supply of the femoral head and gluteal muscles. G Max—gluteus maximus origin; GMed—gluteus medius origin; G Min—gluteus minimus origin; Ob Int—obturator internus; Ob Ex—obturator externus;QF—quadratus femoris.

Figure 3 Elementary and associated fracture patterns.1

J. McMaster, J. Powell142

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Acetabular fractures 143

a wall fracture if it is limited to the acetabularwall. It is accepted, however, that with this systemthere is the potential for overlap between a largewall fracture and a column fracture. However,isolated wall fractures do not tend to extend intothe sciatic notch, involve the quadrilateral plate orextend into the obturator ring.4

Approximately 50% of acetabular fractures areeither posterior wall or both columns.

Pathology

Motor vehicle accidents are the most commoncause of acetabular fractures and the type offracture has been shown to correlate with directionof impact. In the majority of cases, the acetabularfracture will result from impact transmitted to theacetabulum through the femoral shaft or greatertrochanter.1 The type of fracture will also bedependent on the hip position at the time ofimpact. Frontal collision with an impact appliedthrough the axis of the femur results in fractures ofthe posterior wall and column. An adducted legposition predisposes the occupant to a posteriorwall fracture and an abducted hip a posteriorcolumn fracture. Loading through the greatertrochanter (e.g., side impact) is postulated tocause anterior wall and column fractures, trans-verse, T-shaped and both column fractures.

Assessment

General

All acetabular fractures should be assessed inaccordance with ATLSs protocols. In one largeseries reported from a tertiary referral centre,5

56% of acetabular fractures had at least oneadditional injury (19% head injury, 8% abdominalinjury, 18% chest injury, 6% genito-urinary, 35%extremity injury, 4% spinal injury).

Specific

Dislocation of the femoral head is reported in32–39%5,6 of acetabular fractures. Anterior disloca-tions in association with acetabular fractures arevery rare. Damage to the femoral head is commonlyseen. Preoperative sciatic nerve injury was re-ported in 12% of Letournel and Judet’s series of 940patients. Sciatic nerve palsies are frequently seenin association with posterior dislocation and mostcommonly involve the peroneal branch. Recovery

from sciatic nerve injury is variable. In contrast,femoral nerve injury is very rare, and the recoverygood. Preoperative assessment of femoral nervefunction is important as injury is more frequentlyassociated with intraoperative trauma. Acetabularfractures in isolation rarely cause haemodynamicinstability but this may be a feature of anassociated pelvic fracture. Open fractures arereported with an incidence of p1%.5,7 Closed de-gloving injuries (Morel-Lavallee lesion) occur in upto 16% of patients.7 The injury is the result of thesoft tissue being stripped away from the fascia andis associated with haematoma, fat necrosis andischaemic skin flaps. Microbiology cultures takenfrom these areas have demonstrated high rates ofbacterial colonisation (46%)8 despite the closednature of the injury. Surgical skin incisions may alsofurther compromise skin viability. It has beenrecommended that the injury should be surgicallydebrided, before or during acetabular surgery,through an incision centred on the lesion. In mostcases, the de-gloved area should be left open andallowed to heal by secondary intention.8

Labral tears and avulsions are a constant featureof some fractures. This problem is seen particularlywith transverse fractures and it has been recom-mended that these lesions may require resection orrepair.

Investigations

X-ray

The X-ray assessment of acetabular fractures iswell described using the AP and Judet views (iliacand obturator obliques). Each view allows anoptimum view of different aspects of the anatomyrelevant to acetabular fractures. On the AP viewthe ilio-pectineal and ilio-ischial lines representoutlines of the anterior and posterior columns,respectively (Fig. 4). The obturator oblique demon-strates the obturator ring, posterior wall and lowerportion of anterior column. This is the best view toobserve the ‘spur’ sign which is frequently seen inboth column fractures. The spur is formed by theinferior apex of the intact ilium which is formedwhen both columns are split from the sciaticbuttress. The iliac oblique demonstrates the iliacwing, greater sciatic notch, posterior column andedge of anterior wall. It is important to appreciatethat these views are obtained by tilting the patient451 on each side with the X-ray tube and filmvertically aligned. Views obtained by tilting themachine result in significant distortion. Disruption

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Figure 4 Radiological assessment: A—AP pelvis; B—iliac oblique; C—obturator oblique. AW—anterior wall;AC—anterior column; PC—posterior column; PW—posterior wall; OR—obturator ring.

J. McMaster, J. Powell144

of the various landmarks described will allow thefracture pattern to be interpreted. To interpret theAP and Judet views a systematic approach shouldbe used.4 In addition to looking for ilio-ischial andilio-pectineal line disruption, for posterior andanterior column fractures, respectively, it is re-commended that an assessment be made of theiliac wing and obturator ring using the appropriateoblique views. A fracture extending into theobturator ring is representative of a T-shaped orboth column fractures. If the fracture extends intothe iliac wing above the acetabulum, then ananterior column fracture must be present.

AP and Judet views also allow the roof arcs, asdescribed by Matta and Merritt,9 to be determined.On each of the three views, two lines are drawnfrom the geometric centre of the femoral head:one line vertical and the other to the fracture. Theangle between these two limbs is recorded. Medial,anterior and posterior roof arc measurements arerecorded from the AP, obturator oblique and iliacoblique, respectively. These measurements allowthe amount of superior intact acetabular dome tobe described.

CT

CT allows the fracture pattern to be assessed inmore detail and provides valuable information withregard to comminution, marginal impaction (in wallfractures) and intra-articular fragments.

Clues to the fracture pattern can be determinedby observing the direction of the fracture lines onthe CT. On the axial views, splits in the coronalplane often represent column fractures. Sagittalsplits, in the roof of the acetabulum, are seencommonly with transverse or T-shaped fractures.Oblique fractures that do not extend into thequadrilateral plate are seen with wall fractures.

CT scans can help differentiate multi-fragmen-tary T-shaped from both column fractures. T-shaped fractures have at least one part of theacetabulum attached to the sacrum via the sciaticbuttress.

Initial treatment

Reduction

Acetabular fractures are frequently associated withdislocation. It is important to perform and maintaina reduction as soon as possible. Persistent disloca-tion has the potential to influence long-termoutcome. A dislocated femoral head is susceptibleto cartilage necrosis secondary to point loading,and avascular necrosis (AVN) as the result ofa compromised blood supply. Overlying neuro-vascular bundles may also be compromised; thesciatic nerve is particularly at risk with posteriordislocation.

Reduction will require conscious sedation orgeneral anaesthetic. The use of muscle relaxantsis preferable to facilitate an atraumatic reduction.Following reduction a dynamic assessment ofstability should be made as this may influencemanagement if non-operative treatment is beingconsidered.10

Reduction can be maintained with skin orskeletal traction. Traction also helps to preventshortening and minimise difficulty in reduction,especially when reduction is delayed.

Careful radiological assessment must be made toensure a congruent reduction. If there is anincongruent reduction on the AP pelvis X-ray, orthe patient is being considered for non-operativetreatment then a fine cut (p3mm) CT scan shouldbe performed to detect intra-articular fragments.

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Acetabular fractures 145

Venous thrombo-embolism prophylaxis

Pelvic and acetabular fractures are both associatedwith significant risk of venous thrombo-embolism(VTE). There remains significant controversy overappropriate VTE prophylaxis. Chemical prophylaxisshould not be considered until the patient has beenshown to be haemodynamically stable. It is be-lieved mechanical prophylaxis has some benefit,and can be considered immediately. Patients whoexperience a significant delay in operative treat-ment or who have not received optimal prophylaxisshould be considered for further investigation and,where proximal clot is identified, an inferior venacaval (IVC) filter. Venography remains the goldstandard technique as newer techniques, MRI andCT venography, have demonstrated high falsepositive rates and unnecessary use of IVC filtersshould be avoided. A recent survey11 of traumasurgeons dealing with pelvic and acetabular frac-tures reported that routine preoperative screeningwas performed by 48% of surgeons, with themajority using ultrasound. Approximately 3

4 usedchemical prophylaxis, 3

4 used mechanical prophy-laxis and 1

2 used at least one method.

Non-operative treatment

Indications

For non-operative treatment to be considered, thehip has to be stable, and the femoral headcontained within sufficient congruent weight bear-ing acetabulum.

Displaced fractures involving the columns orwalls have the potential to cause loss of con-gruence between the femoral head and acetabu-lum. If the fracture occurs within the superior partof the acetabulum it will both reduce the surfacearea involved in weight bearing and cause instabil-ity. In single column fractures, significant displace-ment within the weight bearing dome will alwaysresult in incongruity as the intact column remainsattached to the axial skeleton.

Wall fractures do not usually significantly affectthe weight bearing surface area but can causeinstability. Both instability and reduced weightbearing surface area are poorly tolerated by thehip and predispose to early degenerative change.

When considering column fractures there has beensome debate over the criteria used for considerationof non-operative management. Matta and Merritt9 andOlson and Matta12 produced radiological criteriaderived from their clinical experience. Measurements

were proposed based on roof arc angles (see X-raysection). Roof arc angles were measured on the AP andboth Judet views9 and felt to be acceptable if the hipwas congruent and all three roof arc measurementswere X451. This corresponds to an intact superior10mm of acetabulum on the CT scan.12 These assess-ments must be performed out of traction. Tornetta10

performed dynamic stress views using fluoroscopy andfound 7% of patients with roof arcs X451 to beunstable. Vrahas et al.13 performed a biomechanicalstudy and considered medial, anterior and posteriorroof arcs of p451, 251 and 701, respectively, to beindications for operative intervention.

In both column fractures, the columns aredetached from the axial skeleton but are con-strained by the remaining soft tissue attachments.The soft tissue has the potential to hold thefracture fragments and maintain congruity des-pite displacement within the weight bearing dome.This situation is described as secondary congru-ence and has the potential to be treated non-operatively.

Fractures of the acetabular walls should beconsidered separately. Olson and Matta12 felt thatinvolvement of 450% of the posterior wall wasunsuitable for non-operative treatment. A biome-chanical study14 determined that p20% involve-ment of the posterior wall is likely to be stable,X40% is likely to be unstable.

It would therefore be acceptable to make aradiological assessment (plain X-rays and CT) ofstability using the described roof angles as a guide.In those patients that are considered appropriatecandidates for non-operative treatment an EUAshould be considered to allow confirmation.

In summary, non-operative management shouldbe considered in the following circumstances:

�

Co-morbities limiting physiological reserve. � Insufficient bone stock to allow adequate fixa-

tion.

� A hip joint that is congruent within a sufficient

superior acetabular dome to allow it to be stableunder physiological loads.

o

Undisplaced column fractures. o Displaced column fractures that involve theinferior part of the acetabulum.

o

Wall fractures with sufficient intact wall tomaintain hip stability.

�

Congruent both column fractures.

Treatment

If non-operative management is chosen then thepatient must be kept non-weight bearing for 4–8

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J. McMaster, J. Powell146

weeks. Traction through a tibial pin may beappropriate to prevent further displacement. Whenimplemented appropriately, good results areachievable.

Open reduction and internal fixation

ORIF is the treatment of choice in those fracturesthat fail to fulfil criteria for non-operative treat-ment in patients who have sufficient physiologicalreserve.

The timing for operative intervention has beenshown to be important with several studies report-ing poorer results when ORIF is attempted atgreater than 3 weeks post-injury. With progressivedelays reduction becomes harder to achieve. Whenpossible, ORIF should take place at 2–5 days toavoid the increased bleeding seen in the first 48 h.Reduction has been shown to correlate directlywith outcome5 and the clinical results of delayedreconstruction (421 days) is poor in comparisonwith earlier intervention.15 Delay is also associatedwith an increase in VTE and skin problems. UrgentORIF may be necessary in the following circum-stances:

�

Reduction of an associated dislocation of thefemoral head cannot be maintained.

�

Retained intra-articular fragments. � Closed reduction has not been possible. � Closed reduction has resulted in a new onset

neurological deficit.

� Open fracture.

Preoperative preparation

As for all trauma surgery every attempt should bemade to optimise the patient medically. Thepatient should be cross matched for 6 units ofblood as blood loss of 1–2 l, but potentially up to 6 l,is not unusual.5 For this reason a cell saver is alsobeneficial. Surgical preparation is also necessary asthe surgery is complex and intensive for equipmentand manpower. A preoperative plan using allavailable imaging will allow most problems to beanticipated and allow the correct equipment to beavailable.

The appropriate pelvic instrumentation withspecialised reduction aids are required in additionto a radiolucent table and image intensifier. Somefractures will benefit from intraoperative tractioneither using the table attachments or a femoraldistractor. Intraoperative nerve monitoring has

been described but is not routinely used in mostcentres.11 Assistance is mandatory and experiencedassistance is invaluable.

The patient should then be positioned on aradiolucent operating table, and the image inten-sifier is then used to check that satisfactory AP,Judet’s, inlet and outlet pelvic views can beachieved. These views can be obscured by bowelgas or contrast within the GI tract.

Prior to surgery the patient will require prophy-lactic antibiotics. The anaesthetist must be madeaware that muscle relaxants may be required andthat the use of nitrous oxide should be avoided tominimise bowel gas.

Approaches

The primary aim is to achieve reduction and usuallythe approach that allows reduction will also besufficient to place adequate fixation. The surgicalapproach is usually based on the pattern ofdisplacement.

The surgical approach used should allow ade-quate visualisation for direct reduction and fixationtechniques. A useful feature of any approach is theindirect access that can be achieved throughpalpation. This allows an assessment of reductionand facilitates indirect techniques. There are threemain approaches which are used in the majority ofacetabular fractures (Kocher-Langenbeck, ilio-in-guinal and extended ilio-femoral, EIF) and numer-ous reported modifications. In Matta’s5 large series,98% of the cases were treated using one of theseoperative approaches. The remaining 2% had adouble Kocher-Langenbeck and ilio-inguinal ap-proach. The benefits of each approach have to becarefully balanced with the relative risks. Thebigger the approach, the bigger the complicationsbut the smaller the approach the greater thepotential difficulty and the greater risk of mal-reduction.

Kocher-LangenbeckThis standard approach involves and incisioncentred on the greater trochanter with a distallimb along the axis of the femur and a proximallimb directed towards the posterior superior iliacspine (PSIS) (Fig. 5). Fascia lata and gluteus mediusare split and reflection of piriformis, obturatorinternus and the gemelli allows access to theposterior wall and column.

All of the standard approaches that allow accessto the outer table of the pelvis have the potentialto allow visualisation, to a varying degree, ofthe acetabular surface using a capsulotomy and

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Kocher -

Langenbeck

Suitable Fracture Configurations: Posteriorwall; Posterior column; Transverse; Posteriorwall plus posterior column; (Posterior wall withtransverse and T-shaped – if simple otherwiseconsider extended iliofemoral).

Extension 1:Surgical hipdislocation

Suitable Fracture Configurations: As above+ suitable for high multifragmentary transversefractures and associated fractures of thefemoral head.

Extension 2:Triradiate

Suitable Fracture Configurations: Allowsgreater access to iliac crest for the treatment ofboth column fractures with significant posteriordisplacement.

Approach Access

Figure 5 Kocher-Langenbeck incision, extensions and indications.

Acetabular fractures 147

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J. McMaster, J. Powell148

dislocation or distraction of the femoral head. Asurgical hip dislocation can be performed as part ofthe Kocher-Langenbeck and allows direct access tothe entire articular surface of the femur andacetabulum. This is particularly useful when ad-dressing large femoral head fractures. This ap-proach preserves the deep branch of the MCFA andinvolves a trochanteric flip osteotomy that includesthe insertion of gluteus medius and the origin ofvastus lateralis. The trochanter is retracted ante-riorly, a capsulotomy is performed and the hip isdislocated. The blood supply to the femoral headvia the deep branch of the medial femoral circum-flex is at risk. Care must be taken when releasingthe short external rotators. A cuff of 1.5 cm shouldbe left at the trochanteric insertion. An alternativeosteotomy involves a standard trochanteric osteot-omy with reflection of the abductors superiorly offthe pelvis, maintaining the superior gluteal vascu-lar pedicle. This procedure is usually accompaniedby an additional skin incision directed anteriorlyfrom the greater trochanter towards the anteriorsuperior iliac spine (ASIS). This is described as thetriradiate approach.

Ilio-inguinalThe inner table of the anterior column is accessedthrough an approach which detaches the abdominalwall from the iliac crest and opens the inguinalcanal. Iliacus is then stripped from the inner tableof the acetabulum. It requires the mobilisation ofthe contents of the inguinal canal and the femoralneurovascular bundle (Fig. 6).

Many modifications have been described for thisapproach. Most of these approaches aim to allowadditional access to the outer table of the anteriorcolumn. One approach involves a longitudinalextension of the ilio-inguinal incision based on theASIS.

Extended ilio-femoralThis approach is derived from the ilio-femoralapproach described by Smith Peterson and extendsposteriorly along the iliac crest (Fig. 7). Theabductors are reflected off the outer table ofthe pelvis on the superior gluteal neurovascularpedicle.

Surgical tacticIn general, extensile approaches (EIF and triradi-ate) are avoided and a single column approach(Kocher-Langenbeck or ilio-inguinal) is used whenpossible. If a single column approach is used it isusually directed at the column with the greatestdisplacement. If both columns are involved reduc-tion of the least displaced fracture can often be

performed indirectly. If this is not possible it maybe possible to extend the standard approach usingone of the numerous modifications. Double incisionapproaches (Kocher-Langenbeck and ilio-inguinal),either simultaneous or staged, have been describedto allow direct access to both columns. Thedecision on the approach used will depend onexperience and training. Helfet and Schmeling16

reported on 84 complex acetabular fracturestreated using a non-extensile approach (Kocher-Langenbeck or ilio-inguinal) and achieved an over-all acceptable reduction (o2mm step-off ando3mm intra-articular gap) rate of 90.5%. It willalso depend on patient factors such as age, level offunction and soft tissues.

Reduction techniques

IndirectTraction can be applied through the leg or directlyto the pelvis and femur. This will allow reduction inthose situations where soft tissue connection hasbeen maintained. In certain fractures, there is asignificant rotational component to the fracturedisplacement. In these situations, Schantz pins canbe placed directly or under image intensifiercontrol and can be used as joysticks to manipulatethe fracture fragments.

DirectMany direct techniques are used to achieve reduc-tion of these complex fractures. Specific fracturereduction forceps are invaluable. The reductionclamps are varied in their size, angle and offset toaccommodate the wide variety of fracture pat-terns. Temporary screws can be used in conjunctionwith three hole plates or forceps to help tempora-rily manipulate and stabilise the fracture.

Internal fixation techniques

Posterior wallThese fractures are often associated with impac-tion (Fig. 8). Open reduction is necessary withelevation of the depressed articular fragmentswith the underlying subchondral bone. The resul-tant defect is packed with bone graft or bonesubstitute. The fracture is reconstructed andstabilised where possible with lag screws augmen-ted by a buttress plate. In those situations wherecomminution prevents lag screw fixation, springplates fashioned from 1

3 tubular plates can be usedin the buttress mode. These fixation constructshave been shown to be biomechanically superior tofixation with screws used in isolation.

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Ilioinguinal

Suitable Fracture Configurations: Anterior wall; Anteriorcolumn; Transverse (occasional); Anterior column/wall with posteriorhemitransverse; Both column (unless multi-fragmentary posterior column); T-shaped (rare).

Extension 1: +Iliofemoral

Suitable Fracture Configurations: As above + allowsgreater access to anterior hip joint and outer table of iliaccrest.

Approach Access

Figure 6 Ilioinguinal incision, extensions and indications.

Acetabular fractures 149

Column fracturesThe same principles are used as for intra-articularfractures elsewhere in the body. The aim is toachieve a stable anatomical reduction, with com-pression, that allows early mobilisation. This is bestachieved with lag screw fixation and a plate in theneutralisation or buttress mode (Fig. 8). Lag screws

can be placed between columns either through theplate or separately positioned. Biomechanical testshave shown that when plating a column fracturethe construct is stiffest with two screws on eachside with screws placed as close to the fracture lineas possible and at the ends of the plates. As anadjunct to reduction and fixation, cerclage wires

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Approach

Extended

Iliofemoral

Suitable Fracture Configurations: This approach is used occasionally for transverse fractures and all of the associated fracture configurations that cannot be dealt with using a one column approach.

Access

Figure 7 Extended iliofemoral (EIF) incision, extensions and indications.

Figure 8 Pre- and post-fixation of a posterior wall fracture associated with impaction: A—axial CT demonstratingfracture and marginal impaction; B—post-operative axial CTwith reconstructed wall; C—post-operative X-ray with lagscrew and buttress plate.

J. McMaster, J. Powell150

can be placed around the ilium, through thegreater sciatic notch at the level of the ante-rior inferior iliac spine. Using safe corridors withinthe pelvis, column screws can be placed. They canbe placed both antegrade and retrograde and areused in both open and percutaneous techniques(Fig. 9).

Transverse fracturesIf possible these fractures are fixed through a singlecolumn approach that allows sufficient access to

lag and plate one column. As long as reduction isachieved the other column can be stabilised,indirectly, with a column screw (Fig. 10). This hasbeen found to be a stable construct on biomecha-nical testing.

Displaced fractures of the quadrilateral plateThese fractures are difficult to treat as visualisationand access for instrumentation is limited. Oneuseful technique is to use a spring/buttress plate

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Figure 9 Both column fractures treated through ilio-inguinal approach. A—preoperative AP; B—preoperative iliacoblique; C—preoperative obturator oblique; D—preoperative axial CT. Anterior column plate with lag screws placedfrom the anterior to posterior column. Additional plate spanning anterior column fracture through iliac crest. A screwwas used for the re-attachment of the anterior superior iliac spine. E—post-operative AP; F—post-operative iliacoblique; G—post-operative obturator oblique.

Figure 10 Transverse fracture treated through Kocher-Langenbeck approach with posterior plate and anterior columnscrew. Despite the heterotopic ossification this gentleman had excellent function and ROM. Note the vascular clips, atthe sciatic notch, used to control bleeding from the superior gluteal vessels.

Acetabular fractures 151

that prevents the fracture displacing and does notrely on direct fixation.

Total hip replacement

ORIF is not recommended in older patients,especially if there is evidence of impaction orosteoporosis. In these circumstances, a limitedreconstruction and total hip replacement can be

considered. Total hip replacement in the acutesetting can be associated with significant complica-tions. However, in older patients, it can provide asatisfactory alternative to definitive ORIF.3

Rehabilitation

A knee immobiliser during the immediate post-operative period is useful to protect fixation of the

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J. McMaster, J. Powell152

posterior column and wall by preventing hip flexionduring recovery. The neurological and vascularstatus of the limb should be checked and recordedfrequently in the initial post-operative period. Thepatient should receive a short course of prophylac-tic intravenous antibiotics.

Immediate weight bearing of 20–30 lb beforecommencing full weight bearing at 8–12 weeks5,7 isthought to be acceptable, except in those caseswhere fixation is tenuous and initial protection withtraction is beneficial. Limitation of hip flexion to601 is important to protect posterior wall andposterior column fixation.

It is important to review the patient clinicallyand radiologically at 2 weeks to assess for loss offixation. If displacement occurs this is best dealtwith within the first 3 weeks.17

Complications

Heterotopic ossification

It is well established that there is a high incidenceof heterotopic ossification (HO) following acetabu-lar surgery. Although patient factors are relevant,this complication is particularly related to theapproach. Stripping and trauma to the glutealmuscles predisposes to HO formation. Conse-quently, EIF and triradiate approaches have a highreported incidence, 35–57% and 86%, respec-tively,1,6,7 whereas there is a low incidence inpatients treated with the ilio-inguinal approach4.8%1,5 and a moderate risk, 19–26%,1,7,18 with theKocher-Langenbeck.

There is ongoing controversy in the literaturewith regard to the efficacy of prophylaxis againstHO. Indomethacin and radiation have both beenused for prophylaxis and both have been reportedas providing benefit. In comparative prospectiverandomised trials, radiation has been shown to beequivalent to indomethacin as a method of HOprophylaxis.19 The most recent study looking at theeffect of indomethacin on HO formation, a pro-spective randomised trial involving 107 patients,20

did demonstrate that indomethacin had a lower HOrate when assessed by Brooker grade and CTvolumetric analysis. However, this was not statis-tically significant and the authors concluded thatindomethacin provided no advantage. A potentiallimitation of this study is the lack of data on patientcompliance.

An additional consideration is the establisheddetrimental effect of indomethacin on long bonehealing in poly-trauma.21

Single dose or fractionated radiation adminis-tered within 72 h post-operation has been used andin some studies that have reported low HO rates. Atrial using a combination of indomethacin andradiation in patients treated with a posterior orEIF approach reported an overall incidence of 19%of which all were Brooker I.22 Radiation prophylaxisis expensive and there are theoretical concernsabout malignancy and the effect on reproductivecells. In addition, there are logistical difficultiesperforming the treatment in the required timeframe as many patients will be requiring high levelsof nursing and medical support.

Not all patients with radiologically determinedHO have functional limitation.18 Matta5 reported a9% functionally significant (X20% loss in range ofmotion (ROM)) HO rate in a group that received noprophylaxis (2% of ilio-inguinal, 20% of EIF, 8% ofKocher-Langenbeck). The requirement for excisionof HO is reported in only 2–5%.7,18

At present there are no good guidelines for HOprophylaxis. The argument for using prophylaxis isstronger in the presence of certain risk factors: anextensile approach,6,15 significant muscle trau-ma,15 head injury,15 male gender20 and delayedtreatment (421 days).15 Within our unit thepresence of two risk factors is used as an indicationto treat with HO prophylaxis.

Venous thrombo-embolism

The incidence of distal deep venous thrombosis(DVT) is poorly documented in the large studies butan incidence of 3–6%1,16 is reported. The incidenceof pulmonary embolus (PE) is reported as 2–4%1,16

and is believed to be the biggest cause of deathfollowing acetabular fractures. Peri-operativedeath from all causes is reported with a frequencyof 0–2.5%.1,5,7

Infection

In centres involved with treating large numbers ofacetabular fractures, the overall infection rate isreported at 3–5%.1,5,7,23 Deep infection has beenreported with an incidence of 3%.5 Several authorshave reported significantly higher infection ratesearly in their series, related to inexperience andlonger operation times. Infection rates also varydepending on the approach. Extensile approacheshave been associated with infection rates of 8.5%6

whereas the ilio-inguinal approach has been re-ported as having a 3% infection rate.24 Obesity is amajor risk factor.

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Acetabular fractures 153

Nerve injury

The most significant iatrogenic nerve injury follow-ing treatment of acetabular fractures involves thesciatic nerve, 3–11%.1,5,7,16 Care must be takenwith retractor placement and maintaining a flexedknee and extended hip when performing posteriorapproaches. Sciatic nerve injuries also occur withilio-inguinal approaches and this has been attrib-uted to reduction techniques involving flexion ofthe hip and placing the nerve under tension. Toreduce tension in the nerve the knee is kept flexedand the hip extended.

Femoral nerve injury has been reported rarely(1%) following the ilio-inguinal approach.5 A 1%obturator nerve injury has been reported.7

Hip abductor weakness has been noted to be asignificant problem in posterior approaches, andthis has been partly attributed to damage to thegluteal nerves during retraction.

The femoral cutaneous nerve of thigh is frequentlydamaged during ilio-inguinal and EIF approaches butis associated with little significant morbidity.

Vascular injury

Femoral vessel injury is reported in 0.8–2% of ilio-inguinal exposures.1,7 In addition, during thisapproach the surgeon should be aware of a veryhigh incidence of retro-pubic anastomoses betweenthe femoral and obturator vessels. These vesselsneed to be ligated prior to division as they havesignificant capacity to bleed and control may bedifficult.

The superior gluteal artery can be damaged withthe consequence of significant bleeding and thepotential for gluteal muscle necrosis. This compli-cation has not been demonstrated clinically.

AVN is most commonly seen in fractures asso-ciated with dislocation. The incidence variesbetween studies, 3–10%.5,16,18 Although damageof the blood supply to the femoral head occurs atthe time of the injury it can also be damagedintraoperatively. Ganz’s research group have high-lighted the significance of the deep branch of theMFCA and proposed that iatrogenic injury of thisvessel may explain the perceived discrepancybetween reported AVN rates in uncomplicateddislocations treated with closed reduction andfracture dislocations that require ORIF.2

Intra-articular screw penetration

This problem is reported infrequently but can resultin post-traumatic arthrosis and every effort should

be taken to avoid this complication by ensuringgood intraoperative imaging. The spherical shapeof the acetabulum means that each screw onlyneeds to be identified as being out of the joint onone view to confirm its extra-articular position. Auseful technique in this situation is to use the imageintensifier to look down the long axis of the screw.Post-operative CT can confirm screw position

Failure of fixation

In the large reported series, failure of fixation isreported with a frequency of 1–3%.1,5,16 The resultsof revision surgery are less satisfactory than withprimary fixation5 and if revision is required there isbenefit in this being performed early.15

Non-union

Very low rates of non-union have been reported3

but when it occurs it is seen most frequently intransverse fractures with unstable fixation.25 Theuse of indomethacin prophylaxis is also believed tocontribute to non-union.

Osteoarthritis

This is reported by most outcome studies and isattributed to cartilage necrosis, articular incon-gruity and instability.

Cartilage necrosis can be related to irreversibledamage to the articular surface at the time ofinjury. Femoral head damage identified intraopera-tively has been shown to be predictive of a worseprognosis. This may explain why one study5

reported a poor outcome in 32% of their anatomi-cally reduced posterior wall fractures. However,evidence of femoral head damage does notguarantee a poor result.

Articular incongruity (secondary to intra-articu-lar metal work and mal-reduction) and instabilityboth predispose to osteoarthritis as a result ofabnormal loading of the articular surface.

Functional outcome

Studies published from large centres with experi-ence in acetabular trauma report good to excellentresults in approximately 80% of cases.1,5,7 Most ofthe historical data on acetabular fractures wascompiled using the d’Aubigne-Postel scale.1 Thisscoring system is limited in its application as thehighest score does not correlate with a return tonormal activities. A ‘good’ score can be achieved

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J. McMaster, J. Powell154

with a patient complaining of a slight or inter-mittent pain with normal activity; hip flexionlimited to 701 and a slight limp.

Despite the potential limitations of the scoringsystems used, several factors have been identifiedwhich correlate with outcome.

It has been established that the surgeon has alarge influence on outcome. The most frequentlyassociated factor with outcome is the quality of thereduction.1,5,7,16 Anatomical reduction has beenseen to be highly significant for excellent or goodresults and any mal-reduction was associated witha worse outcome.5 As a result the experience of thesurgeon plays an important part in the ability toachieve an anatomic reduction. Several largestudies report a significant learning curve. This isdemonstrated by several surgeons reporting poorerresults at the start of their series.1,16 The timing ofsurgery is also important with delay 43 weeksassociated with poorer functional outcome and ahigh incidence of AVN, OA, HO and sciatic nerveinjury.15

Approximately 10% of hips will be expected tofail within 2 years.3 THR performed in this group isseen to perform less well than in a matched cohortof THR for OA. In addition, acetabular fracturesinitially treated non-operatively, performed betterthan those treated initially with ORIF. The timingand role of THR in acetabular fractures is still beingestablished.

References

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2. Gautier E, Ganz K, Krugel N, Gill T, Ganz R. Anatomy of themedial femoral circumflex artery and its surgical implica-tions. J Bone Jt Surg—Br Vol 2000;82(5):679–83.

3. Tile M, Helfet D, Kellam J, editors. Fractures of the pelvisand acetabulum. 3rd ed. Lippincott Williams and Wilkins;2004. p. 830.

4. Brandser EA, El-Khoury GY, Marsh JL. Acetabular fractures: asystematic approach to classification. Emerg Radiol1995;2(1):18–28.

5. Matta JM. Fractures of the acetabulum: accuracy ofreduction and clinical results in patients managed opera-tively within three weeks after the injury. J Bone JtSurg—Am Vol 1996;78(11):1632–45.

6. Alonso JE, Davila R, Bradley E. Extended iliofemoral versustriradiate approaches in management of associated acet-abular fractures. Clin Orthop Relat Res 1994;305:81–7.

7. Mayo KA. Open reduction and internal fixation of fracturesof the acetabulum. Results in 163 fractures. Clin OrthopRelat Res 1994;305:31–7.

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21. Burd TA, Hughes MS, Anglen JO. Heterotopic ossificationprophylaxis with indomethacin increases the risk of long-bone nonunion. J Bone Jt Surg—Br Vol 2003;85(5):700–5.

22. Moed BR, Letournel E. Low-dose irradiation and indometha-cin prevent heterotopic ossification after acetabular frac-ture surgery. J Bone Jt Surg—Br Vol 1994;76(6):895–900.

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