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Non Union NOF in Young Adult

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TRAUMARECONSTRUCTION Management of neglected/ununited fractures of the femoral neck inyoung adults O. N. Nagi and M. S. Dhillon Department of Orthopaedics, Post Graduate Institute of Medical Education and Research, Chandigarh, India INTRODUCTION Proximal femoral fractures may be extra or intra-capsu- lar injuries, and they occur with about the same fre- quency in the elderly population. They are more common in women, with the inter-trochanteric extra- capsular injuries oc
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  TRAUMARECONSTRUCTION Managementofneglected/ununitedfractures of thefemoralneckinyoung adults O.N.NagiandM.S.Dhillon DepartmentofOrthopaedics,Post Graduate Institute of Medical Education and Research,Chandigarh,India INTRODUCTION Proximal femoral fracturesmaybe extra or intra-capsu-lar injuries, and they occur with about the same fre-quency in the elderly population. They are morecommon in women, with the inter-trochanteric extra-capsular injuries occurring in a relatively older segmentof thepopulation. 1 Intra-capsular femoralneckfractures,known since the advent of medicine, are still a manage-ment enigma, in spite of increased understandingof the technology, diagnostic methods and treatment.In the last century, treatment protocols have evolvedconsiderably fromWhitman’s protocols of spica applica- tion,andhavenowbecomebetterdef|ned. 2 Thisinjuryismost frequently encountered in the elderly population,whereaminor slipmaybe thecause,andisrelativelyun-commoninyoung adults.Themodern literature reflectsa disturbing trend of more injuries occurring in theyounger age groups, and these are usually the result of high-energy trauma. At whatever age they present,complications are frequent, with union rates beingrelatively low; a combination of factors is responsiblefor this. TERMINOLOGY Basically, all femoral neck fractures, where the fracturelineisprimarily withinthejointcapsule,arecalled‘Intra-capsular’ fractures of the hip.Fractures that involve thearticular surface should be considered a more complexvarietyandsomeauthorsevenconsider themseparately.A host of names has been given to intra-capsular pat- terns, varying from‘transcervical’ to‘Subcapital’injuries,and the prognosis in these cases is much worse.On theother hand, those at the base of the neck, are primarilyextra-capsular and are separate entities, requiringdifferent forms of stabilisation, and having much betterunionrates. EPIDEMIOLOGY KovalandZuckerman, 1 reportedthatin1994,250000fe-moralneck fractures occurredin theUSA(projected1.3million fractures worldwide). This rate is expected todouble by 2025. Martin et al. found increasing incidenceof fractures of the proximal femur, which could not beexplained by changing demographics alone. 3 Approxi-matelyhalfof thefracturesreportedinallstudies arein- tra-capsular, and the average age of these cases isapproximately 80 years, with 75% being females. Con-versely, when the injury occurs in young adults, most of  these cases are healthy adults, with no super-addedpathology, and good bone stock.The velocity of traumaisalsohigher,withalargernumberofassociatedinjuries. ARTERIALBLOODSUPPLY A lot of detail has now been gleaned about the bloodsupply to theproximalendof thefemur,whichhas someunique features. The arterial supply becomes tenuousafterinjury,endangering thefemoralhead,riskingsubse-quent avascular necrosis and collapse. The arterial ar-cades which supply the blood to the head and neckmaybe divided into three major groups; these wereclearlydescribedby Crock. 4 (1) An extra capsular arterial ring, located at the baseof the femoralneck, andencirclingit.(2) Ascending cervicalbranches arise from this arterialringon the surface of the femoralneck.(3) The arteries of the ligamentum teres, which alsosupplya signif|cantpartof thebloodsupply.The extra-capsular arterialringis formedposteriorlybyalargebranchof themedialfemoralcircumflexartery Correspondence to: ONN.1027, Sector 24, Chandigarh 160024, India.Tel.: +91172 728851;Fax: +91172 744401 CurrentOrthopaedics (2003) 17, 394--402  c 2003 Elsevier Ltd. Allrightsreserved.doi:10.1016/S0268-0890(03)00046-X  and anteriorly by a branch from the lateral femoral cir-cumflex artery.The ascending cervical branches or reti-nacularvesselsascendonthesurfaceof thefemoralneckin anterior, posterior, medial, and lateral groups; thelateral vessels are the most important.Their proximity to the surface of the femoral neck makes them vulner-able to injuryin femoralneck fractures. As the articularmarginof thefemoralheadis approachedby theascend-ingcervicalvessels, a second, less distinctringof vesselsis formed, referred to by Chung 5 as the subsynovial in- tra-articular arterial ring. It is from this ring of vessels that vessels penetrate the head and are referred to as the epiphyseal arteries, the most important being thelateral epiphyseal arterial group supplying the lateralweight-bearing portion of the femoral head. Theseepiphysealvesselsarejoinedbyinferiormetaphysealves-sels andvessels from theligamentum teres. MECHANISMOFINJURY In contrast to the elderly population, femoralneck frac- tures in young adults can only occur with signif|cantforce.Kocher suggested two mechanisms of injury in allage groups. In the elderly, the injury is more commonlydue to a directblow over the greater trochanter duringafall.Inyoungadults,themorecommoninjuryisalateralrotation force applied to the extremity, with or withouta proximally directed force. With deforming force, theheadis held f|xedby the anterior capsule andiliofemoralligaments while the hip rotates externally. By this rota- tion, the posterior cortex of the neck impinges on thelip of the acetabulum, and the neck buckles.This leads to a complete break in the anterior cortex, and alsocauses buckling of the posterior cortex (Fig. 1a and b).This also explains themarkedposterior comminution of  theneckoften seenwith thisinjury. RADIOLOGY Theradiologicalexamination 6 shouldinclude theroutineviews (AP, andlateral), andin the cases of fractureswithneglect, some special views maybe benef|cial. The APview should be taken in maximum internal rotation of  the limb to evaluate the extent of neck resorption; itmayalsobeagoodidea,incaseswithproximalmigrationof the neck, to take X-rays using the‘push pull’method, to see how much the trochanter can be brought downwithmanualtraction.Inspecialcases,itmaybeadvanta-geous to use CT scans to determine the extent of comminutionof theposteriorcortex;MRIcouldbedonefor assessment of the vascular status of the femoralhead, as bone marrow changes may give indirectevidence ofpresence orlackof vascularity. Figure1  (a)Linediagramshowingmechanismoffemoralneckfracturewithexternalrotationforce.The anterior aspectofthefractureisopenedout(A),whilethereisbucklingoftheposteriorcortex (B). The anterior blood vessels are invariably torn (C)while the posterior vessels may potentially be intact (D).(b) X-ray photograph (lateral view) showing break in anteriorcortex (A) andbucklingofposteriorcortex (B). FEMORALNECKINYOUNGADULTS 395  CAUSESOFDELAYEDHEALING/NON-UNION In all intra-capsular fractures, the synovial fluid bathing the fracturemayinterferewith thehealingprocess. An-giogenic-inhibiting factorsinsynovialfluidcanalsoinhibitfracture repair. Additionally, as the femoral neck has es-sentially no periosteal layer, all healing must be endo-steal. These factors, along with the precarious bloodsupply to the femoral head, make healing unpredictableandnon-unions fairly frequent.In the developing countries, we still see patients withdelaysintreatmentdue topoormedicalfacilities,misseddiagnosis(especiallyinpolytraumatisedyoungadults),orimproper surgicaltechniques.Thefactorsknownto con- tributetonon-unionof thefemoralneckincludevascularinsuff|ciency, inaccurate reduction, and loss of f|xation.The f|rst one is usually not in our control, but the latter two, along with delayed diagnosis, make up a signif|cantnumber of cases still encountered in the developingworld.In the recent past, improved treatment, earlier diag-nosis, and an understanding of the treatment regimensof femoral neck fractures has drastically reduced theincidenceofnon-unionafter theseinjuries.Inspiteofthis,non-unions are still estimated to occur in 10--20% of patients in the developed world in all age groups.Withanatomical reduction and stable f|xation, the incidenceof non-union should be acceptably low. However, in ameta-analysis of 106 reports of displaced femoral neckfractures(seenatallages)byLu-Yao etal.,non-union oc-curredin a cumulative 23--37% of fractures. 7 The appropriate treatment depends on several fac- tors, including the age andphysical status of thepatient, the viability of the femoral head, the amount of resorp- tion of the femoral neck, and the duration of the non-union. 8 Most patients with femoral non-unions are over60 years of age; these cases arepoor surgicalcandidatesfor repeated surgical interventions, and extreme osteo-porosis decreases the eff|ciency of any internal f|xation.Theanswerinthisagegroupissimple,andareplacementarthroplasty as a primary procedure gives reliableresults. In the younger age group, however, where it isimportant to save the femoral head, and in children,where some potential for growth is still present, theoperation should be devised so as to make all attempts to save theheadof thefemur.Thisisnot alwayspossible,as delaysin treatmentinvariablylead toproblems. PROBLEMSWITHDELAY The effect of surgical delayon theincidence of avascularnecrosisandnon-unionafterdisplacedfemoralneckfrac- ture has been reviewedby several investigators.Massie 9 demonstrated a direct relationship between delay of fracture reduction and incidence of avascular necrosis(AVN): fracturesreducedwithin12h of injury had a 25%incidence of AVN, whereas for fracture reduced more than 7 days after injury, theratewas100%.Manninger et al. 10 reported a signif|cantly lower inci-dence of segmental collapse in patients treated within6hofinjury,whentheycomparedtwosubsetswhowere treated early and late. At1-year follow-up,1.9% of frac- tures in the early treatment group and19.3% of cases in the delayedtreatmentgrouphadsegmentalcollapse; fol-low-up at 6--10 years revealed segmental collapse ratesof 36.8% in the early treatment group and 63.9% in thedelayed treatment group. Additionally, more patients in the delayed treatment group developed non-union. It isalso interesting to note that in the early treatmentgroup, segmental collapse often involved only a portionof the femoral head, whereas total head involvementwas much more common in the delayed treatmentgroup.This showshow the treatmentbecomesmoredif-f|cultincaseswhohavea signif|cantperiodofdelayprior to surgery. EVOLUTIONOF TREATMENTMETHODS Historically,mostof thesecasesweremanagedbydiffer-entkindsofosteotomies,inwhichthefemur wasdividednear the lesser trochanter and was either angulated toprovide a line of weight bearing more directly beneath thefemoralhead,orwasdisplacedmedially. 11 Thesewerenotuniversally successful, as they were operations doneaway from the fracture site, and did not ensure fractureunion,orre-vascularisationof thehead.Two typesof os- teotomy or modif|cations of them have been used to treat non-unions of the femoral neck: the displacementosteotomy (McMurray), made justproximal to or at thelesser trochanter, and the angulation osteotomy(Schanz), made through or just distal to the lesser tro-chanter.ThedisplacementosteotomyofMcMurray 12 heldcentre-stageforalong time,andinourcountry wasonlydiscontinued in the late1970s as the primary treatmentmodality, whenmorereliablemethods ofosteosynthesisbecame available.The mechanical advantages of an osteotomy are that theline of weightbearingis shiftedmediallyandthat theshearing forceatthenon-unionisdecreasedbecausethefracturesurfacetendstobecomemorehorizontal.Theseadvantages are greater after the angulation osteotomy than after the displacement osteotomy. A serious disad-vantage is produced if the femoral neck and head areplaced in an extreme valgus position, and this positionmustbe avoidedifpossiblebecauseit shortens theleverarm between the trochanter, on which the abductormuscles pull, and the head, whichis the fulcrum.In1936,Pauwels 13 calledattention to thismechanicalproblem. 396  CURRENTORTHOPAEDICS  In treating non-unions with a viable head, the angula- tion osteotomy was not intended to provide a partialpelvic supportbutrather toshiftthelineofweightbear-ingmediallyand to change theinclination of the fracturesurfaces.Blount 14 devisedabladeplatethatheldthefrag-ments securely without external support. The angula- tion osteotomy is currently f|xed with variable angledhip screws and side plates, and several more recentreports have indicated its usefulness. Marti et al. 15 reported union in 86% of 50 non-unions treated withinter-trochanteric osteotomy alone; three non-unionshealedafterrevisionprocedures.Another operation, arthrodesis, involves differentprocedureswherethehipisfused,andismentionedonlyfor the sake of completion. Some authors advocateit asan option in children and adults less than 21years of agewho have frank non-unions in which the femoral headisnot viable. The advantages of an arthrodesis for non-unionof thefemoralneckarefreedomfrompainandsta-bilityduring weightbearing; thismaylead to a useful ex- tremity that allows ambulation and weight bearing,albeitwithalimp.Thiscanoccasionallyberecommendedin adultsunder the age of about 50 years whoseworkisheavy manual labour, or after the failure of previoussurgery with an infection in the hip. A major disadvan- tageis the delayedonsetof severe degenerative changesin the spine and contralateral hip, as well as signif|cantdiff|cultyin subsequentconversion to an arthroplasty.In thepresentday scenario, thebestoptionperhapsis to obtain union in these fractures by the best possiblemethod, and to avoid the development of AVN and theensuing collapse of the head. In1984, the senior authorpublished the results of cases with delayed or neglectedfractures which were treated by a combination of inter-nal f|xation, accurate reduction and f|bular osteosynth-esis. 16 The good results seen in those cases lead us tomake this the primary treatment method in all cases of femoral neck fracture seen inyoung adults, after signif|-cant periods of delay in treatment (6 weeks or more).Consistently reproducible union rates and a loweredincidence of AVN allowed us to expand our indications to include those cases in which previous surgical proce-dureshadfailed, 17 andeveninchildren. 18 LITERATUREREVIEW The few reports that have been published concerningneglected fractures of the femoral neck in young adultsemphasise that the outcomeisusuallypoor. 19 Early accu-ratereduction and f|xationunder compression has givengoodresults,butindevelopingcountriesearlyoperationis not always possible. This can lead to problems of management.It is desirable to try to salvage the femoral head inyoung adults, and this often calls for some form of bonegraft. The literature reports many techniques, 20--22 ranging from of the use of Phemister grafts, 23 vascu-larised 24 or muscle pedicle grafts, 25,26 and f|bular graftswith or without osteotomy, 27--29 but none of these stu-dies has been prospective or large enough to allow anyconclusion about thebest form of treatment.Lifeso andYoung, 30 concluding that non-union in young adults wasdiff|cultto treat,feltthatvalgusosteotomygaveaccepta-ble results. However, displacement osteotomy is nolonger popular, as it interferes with subsequent arthro-plastyproceduresif thereareanycomplicationswiththeprimary operation. 31 The best results come from someformofbonegraftwithstablef|xation.Baksi 25 haspopu-larised the use of the muscle pedicle graft proceduredescribed by Meyers, 26 and it has been used for ne-glected cases as well as for cases with established AVN.This procedure basically uses the posterior approach,whichin the authors’opiniondamageswhateverresidualblood vessels remain in this area after the injury.Thereare now some reports in the literature which cautionagainst the use of the posterior approach. 17 In cases inwhich a Meyers muscle pedicle graft had been delayedfor more than 3 months after injury, Johnson and Brockreportedup to a 75% rate of non-union. 32 On the otherhand,excellentresultshavebeenobtainedwithopenre-duction and vascularised iliac-crest grafting, using ananterior approach. 24 However, the procedure involves the use of specialised instrumentation and is technicallydemanding, and since only a few cases have been re-portedthelong-term acceptabilityhas yet tobeproven. Operativetechnique This involves open reduction of the fracture, whichshould be accurate and stable, special modif|cations in the anterior capsular incision to try and save anteriorvessels, and the use of a f|bular graft to supplement thef|xation achievedbyan AO cancellous screw. Anterolateralapproach (modif|edfromWatson--Jones) Since theinception of themethodologyof f|bular osteo-synthesis, the approach used at our institute has beenone modif|ed from the standard Watson--Jonesapproach.This positions thepatientin a semi-supinepo-sition, with a sandbag under the buttock, and allowsgoodradiologicalimagingaswellasmakingmanipulationof the leg easier.This approach allows an easy exposureof the anterior aspect of the hip through the inter-mus-cular interval between the sartorius and the gluteusmedius muscles, by splitting the iliotibial band and the tensor fascia lata muscle.The skinincisionis about15cmlong;insteadof thestraight,longitudinalincisioncentredover the greater trochanter, we employ a curved inci-sion, starting from an inch posterior to the anteriorsuperior iliac spine, to the greater trochanter, and thendistally for about 6cmparallel to thelateral shaft of the FEMORALNECKINYOUNGADULTS 397
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