PERIACETABULAR OSTEOTOMY (PAO) All information here is general in nature and needs to be tailored to your circumstances

OverviewPAO surgery is a hip preservation surgery performed to correct a deformity in the acetabulum (hip socket) such asacetabulardysplasia.Ifthisconditionremainsuntreated,secondaryarthritiscommonlydevelops.Therefore,inordertorelieve symptoms and improve theprognosis of thehip, this surgery is done to correct thebony anatomyandhelpnormalizetheloadacrossthejoint.“Periacetabular”meansaroundtheacetabulum(hipsocket).“Osteotomy”meanstocutbone.Therefore,periacetabularosteotomymeanstocutthebonearoundtheacetabulumandrepositionthehipsocket.ThePAOisaveryeffectiveprocedureforthetreatmentofsymptomaticacetabulardysplasia.MrSlatteryistrainedinaminimallyinvasiveformofperiacetabularosteotomyusingagroincreaseincision.Anincisionismadeacrossthefrontofthehipjointtoallowexposureofthehipandsurroundingpelvis.Thenspecialisedinstrumentsare used with X-ray vision to perform controlled cuts of the pelvis and free the acetabulum from the pelvis. TheacetabulumisrepositionedandfixedinthenewpositionwiththreeorfourscrewsafterfurthercheckswithX-ray.Thisisahighlyspecialisedprocedurewhichisdonebyonlyafewsurgeonsworldwide.ItwaspioneeredinSwitzerlandwithProf.Ganz,whichiswhereDrSlatteryundertooksub-specialistfellowshiptrainingtolearntheartofthisprocedure.

Apelvicmodelisshownanddemonstratesthebonycutsandrepositioningoftheacetabulum.Thegapsbetweentherepositionedbonefillinwithnewbone,justlikethehealingofafracture.

X-raysofayoungfemalewithbilateralhipdysplasiaareshown(left).ShehadPAOsdonetobothhipsandhasanexcellentresultinbothhips(right).Manypatientswithhipdysplasia(shallowsocket)haveotherproblemswithinthejoint(cartilagetears)and/ormayhaveadeformityof the femoralhead (ball) of femurbone.Commonly, theseotherproblemsare treatedduring thePAOprocedure.

Occasionallythereisalsoadeformityofthefemurthatmustbecorrectedatthetimeofsurgerybyaproximalfemoralosteotomy(PFO).Thisinvolvescuttingandrepositioningtheupperportionofthefemur(thigh)bone.Ifthisisneeded,asecondincisionismadeontheoutsideofthehipandthefemurisrepositionedandfixedwitharod,orametalplateandscrews.

Preoperativex-raysofa19yrmalewithdeformityofboththehipsocketandfemursecondarytoPerthesDisease(right).4yrsaftersurgerywiththeosteotomiesofboththeacetabulumandfemur,thispatienthasnohippainandanexcellentresultfromsurgery(left).Thehospitalizationtimeistwotofourdaysandfullrecoverytakesfourtosixmonths.Themajorityofpatientsexperiencemajorreliefofpainandbecomequiteactiveafterrecoveryfromsurgery.WhilethePAOisanextremelyeffectivehippreservationprocedure,itmaynotcreateacompletelynormalhip.EvenifthePAOiseffectiveinadolescenceorearlyadulthood,somepatientsarelikelytorequireatotalhipreplacementsurgerylaterinlife.RecoveryAfteraPAO,patientsareusuallyoncrutchesforfourweekswith“touchweightbearing.”Acontinuouspassivemotion(CPM)machineisusedtoassistjointhealingandmaintainhipmobility.Weightbearingisincreasedgraduallyastoleratedatfourweeks,andanticipateunassistedwalkingatsixtoeightweeks.Strengtheningexercisesandnonimpactactivities(cycling,swimming,elliptical)arealsoprogressedatfourweeks.Forathletes,joggingstartsthreemonthsaftersurgeryandreturntofullsportisallowedatfourmonths.ThetotalrecoverytimefromPAOsurgeryisfrom6-12months.Risks and ComplicationsPAO Surgery is very complex, and it can have significant complications. Dr Slattery employs numerous techniquesthroughout theprocedure tominimize surgical risks,but complications can still occur. Risks specific toPAO surgeryinclude:

- NerveDamage:permanentnerveinjuriesareveryrarefollowingPAO,somepatientsmayhavenumbnessdowntheoutsideoftheirthighduetostretchingofthenervestotheskin,thisusuallyrecoversin3-6months.ThereisaverysmallrisktothelargefemoralandsciaticnervesduringPAO,whichcanleavepermanentsensorylosstotheleg.

- Bleeding: as the pelvic bone has to be cut numerous times, there can be significant blood loss from thisoperation.DrSlatteryroutinelyusesbloodsalvagetechniquestominimizetheuseofbloodtransfusionspostoperatively.

- Fracture:asDrSlatteryusesaminimally invasivePAOtechniquewithX-rayguidance there isa small riskoffracture,whichisnormallydetectedatthetimeoftheoperation

- NonUnion:thisoccurswhenthecutbonesdonothealtogether,thisisveryrarefollowingPAO- Infection

FAQs WhencanIwalkafteraPAO?Partialweight-bearingandwalkingwithcrutchesisallowedimmediatelyafteraPAO.WegetallpatientsmobilisingDay1aftertheiroperationoncrutches.WhencanIdriveafteraPAO?Youshouldnotdriveforatleast48hoursafterananaesthetic.After48hours,yourabilitytodrivewilldependonthesideyouhadyouroperation,leftorright,thetypeofvehicleyoudrive,manualorautomaticandwhattypeofpainreliefyouaretaking.Itisgenerallyreasonabletodrivewhenyouareconfidentwithwalkingandcanfullyweight-bearonyouraffectedside.Theusualrecommendationis4weeks.WhencanIworkafterananteriortotalhipreplacement?Yourreturntoworkwillvarydependingonthetypeofworkyouareengagedin.Mostpeoplecanreturntoofficeworkwithin2weeks.Morestrenuousmanualwork,mayrequireyoutotake6-12weeksbeforereturningtofullduties.WhencanIplaysportsafteraPAO?Lowimpactactivities,suchascyclingandswimming,canbecommencedfromweek6.Highimpactactivities,suchasrunning,orexcessivetwistingsuchasduringtennisorgolf,arebestavoidedfor12weeksaftersurgery.HowlongwillItaketohealafteraPAO?Thewounds take7-10days toheal.Mostpatients improvedramatically in the first 6weeks.Occasionally, thereareperiodswherethehipmaybecomesoreandthensettleagain.This ispartof thenormalhealingprocess.Continuedimprovementsmaybegainedupto1yearpost-surgery.HowmuchpainwillIexperienceafteraPAO?Most patientswill have somediscomfort after surgery. A local anaesthetic is injected around thewoundduring theprocedureandalocalanaestheticcatheterisplacedinthewoundaftertheproceduretominimiseanypainyoumayexperience. We will carefullymonitor your post-operative course and aim to keep you as comfortable as possiblethroughout.