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Introduction

Complaints relating to the musculoskeletalsystemrepresentthereasonsfor6.1%ofvisitstopaediatricclinics,andthecomplaintofkneepainaccounts for approximately 33% of these visits(1).Anteriorkneepaindefinesacomplaintofpainin the anterior part of the knee. This complainttypically arises from the patellofemoral jointand the surrounding tissues that reinforce thisjoint; however,with regard to the epidemiologyofandtheapproachtokneepain,itmayoccurinassociationwithhypermobility of the knee joint(2)andosteochondrosisduringadolescence(3). Kneepainseeninchildrenmayhaveseveralorthopaedic causes. Sinding-Larsen–Johanssonsyndrome (SLJ), Osgood–Schlatter syndrome(OSS), patellar tendinitis, patellofemoralsyndrome, fat pad syndrome (FPS), plicasyndrome,lateralretinacularpain(LRP),iliotibialbandsyndrome(ITBS),osteochondritisdissecans,joint mouse, meniscus tear, ligament tear, andchondral injuries can cause anterior knee painleading to internal irregularity in the knee (4).Othercausesofkneepainmaybediseasescausinginflammation such as juvenile rheumatoid

arthritis, infection, and neoplasms. Childhoodkneepainmaybeasignofanorthopaedicdisorderorasystemicdisease,oritmaybereferredpain.Itshouldbekept inmindthat theactualreasonfor paediatric knee pain may be referred hipjoint pain. In the patients with no identifiablepathologyonkneeexamination,hipexaminationmustalwaysbeperformed.Thepathologiesofthehipthatmayleadtokneepainaredevelopmentaldysplasia of the hip, transient synovitis, slippedcapital femoral epiphysis, septic arthritis of thehip,sicklecellanaemia,stressfracturesofthehip,andLegg–Calve–Perthesdisease(4).

Case Report

A 7-year-oldmale patient presented to ourpolyclinic with the complaints of the pain inthe left knee and impeded walking beginning 2weeksprior.Hispainbecameworsewithactivity;however, sometimes he also suffered from painduring rest. The medical history of the patientrevealedthathehadvisitedanorthopaedicclinic9monthsearlier;theroentgenogramsofthekneeand laboratory tests were normal, and he was

Case Report Knee Joint Pain May Be an Indicator for a Hip Joint Problem in Children: A Case Report

Ayse Esra Yilmaz1, Hakan atalar2, Tugba tag1, Meki Bilici1, Semra Kara1

1 Department of Pediatrics, Faculty of Medicine, Fatih University, Alparslan Turkes Caddesi No: 57, 06510, Ankara, Turkey

2 Department of Orthopedics, Faculty of Medicine, Fatih University, Alparslan Turkes Caddesi No: 57, 06510, Ankara, Turkey

Submitted: 16Jul2010Accepted: 1Sep2010

Abstract Knee joint pain is one of the most common complaints related to the skeletal systemencounteredbypaediatricians.Kneejointpaingenerallyoccursastheresultofhypermobilityandgrowing pains, though disorders manifesting as arthritis/arthralgia and orthopaedic problemsshouldbe considered in thedifferential diagnosis.A thorough and careful physical examinationand laboratory and radiological findings are of importance for an accurate diagnosis. Althoughtreatmentshouldbebasedontheaetiologyofthekneepain,non-steroidanti-inflammatorydrugscanbeusedtoalleviatethepain.A7-year-oldmalepatientpresentedwithrecurringpainintheleftknee.Physicalexaminationofthepatient,laboratorytests,andradiologicalexaminationofthekneejointwerenormal;roentgenogramsperformedforapresumedhipjointproblemrevealedafocalcorticaldefectontheleftfemoralheadandanincreasedeffusioninthelefthipjointspacecomparedwiththerightcounterpart.Withthiscasereport,wewouldliketohighlightthatpaediatrichealthanddiseasesspecialists(paediatricians)shouldconsiderhipjointpathologieswhenpatientspresentwithkneepain,particularlykneepainwithanunidentifiedaetiology.

Keywords:: children, diagnosis, hip, joint pain, knee, referred pain

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prescribednon-steroidanti-inflammatory(NSAI)drugs. His pain was relieved by these drugswithin1week.Thepreviousmedicalhistoryofthepatientwas unremarkable, and no other personinhisfamilyhadsimilarcomplaints.Onphysicalexamination,vitalsignswerestable.Therewasnorecognisablewarmth, hyperaemia or swelling inthejoints,butmovementsoftheleftkneeandthelefthipwerepainful.Examinationofotherareaswasnormal. Laboratory test results were as follows:haemoglobin 12.9 g/dL, white blood cell count11 300/mm3 (on peripheral blood smear, 58%neutrophils, 33% lymphocytes, 9% monocytes),erythrocyte sedimentation rate (ESR) 8 mm/h,antistreptolysin O titre <25 U/mL, rheumatoidfactor (RF) negative, C-reactive protein (CRP)<1mg/dL,alkalinephosphatase243U/L,calcium8.4mg/dL, and tube agglutination tests for thepresence of the antibodies against Salmonella andBrucella were negative.On the radiologicalexamination, two-sided radiographs of the leftkneewere normal. Anteroposterior comparativeradiography of the hipwas performed, followedbymagneticresonanceimaging(MRI)ofthelefthipbecauseofafocallyticlesionobservedontheleftfemoralhead(Figure1).Afocalcorticaldefectontheleftfemoralheadandanincreasedeffusioninthelefthipjointspacecomparedwiththerightcounterpartwereidentified(Figure2).Aspecificdiagnosis was not made radiologically. Needlebiopsywasnotsuitablebecauseof theanatomiclocation of the lesion, the technical difficulty,and the necessity of anaesthesia. Surgicalbiopsy was not performed because of the riskof avascular necrosis of the femur. The patientwasrecommendedforfollow-upforanassumedbenign bone tumour (e.g., chondroblastoma oreosinophilicgranuloma)inearlyinitialstage,andtheuse of crutchwas recommended.TreatmentwithNSAIdrugswasstartedtoalleviatehispain.Two months later, on clinical evaluation of thepatient, his complaints had regressed; however,nochangewasobservedontheplainradiographs.Heisbeingfollowedforthehipjointpathology.

Discussion

Knee pain is a commonly encounteredproblem in children and adolescents, with aprevalence ranging 4%–30% (5). Diagnosisrequiresobtaininga carefulmedicalhistoryanddoingphysicalexaminationbecausekneepainisanon-specificcomplaint.Localisation,character,time of onset, duration of the pain, association

with activity or resting, factors that aggravateor relieve the pain, mechanical symptoms,neurological symptoms, trauma, inflammatorychanges, haemorrhagic diathesis, and theresponse to analgesicsmust be determined. Forthedifferentialdiagnosis, it is importanttodoathorough anddetailed examination for systemicdiseases as well as local signs such as swelling,redness,andtendernessofthejointaffected.

 

Figure1:Anteroposteriorradiographofthehiprevealingafocallyticlesionontheleftfemoralhead

Figure2:Magnetic resonance imageof the lefthip confirmed a focal cortical defectontheleftfemoralheadandrevealedan increased effusion in the left hipjointspace

 

Case Report |Kneejointpain

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Fordiagnosis,completebloodcount,CRP,andESRarelaboratoryteststhatshouldbecompletedinitially; however, the results of these testsmaynot always be instructive. Microbiological andrheumatological tests directed to aetiology maybedoneusingbothbloodandsynovialfluid,whenneeded(6,7).Theimagingmethodthatshouldbeusedfirst for thediagnosis isplain radiography.Insomecases,magneticresonanceimagingmayberequired. Much of childhood knee pain results fromhypermobility of the joint, transient synovitis,slipped capital femoral epiphysis (SCFE), orgrowth-related factors in adolescents (2). SCFEcanpresentwithvaguekneepaininadolescents,and hip radiographs should be obtained to ruleoutthisdisease.Jointhypermobilityandgrowth-relatedfactorsaregenerallyself-limitingandhavegoodprognoses.Growingpainsoccurinchildrenaged between 4-8 years; occur bilaterally in thethighs,calvesorbehindtheknee;andaregenerallyintermittent.Physicalexaminationandlaboratorytestswerenormal(6).Althoughourpatientwasintheproperagerangeforpainrelatingtogrowthorjointhypermobility,non-organicpathologieswereruledoutinthedifferentialdiagnosisbecauseofpainfulmovementsoftheleftknee. Organiccausesofchildhoodkneepainresultfrom orthopaedic, infectious, or rheumatologicdisordersormalignancies.Septicarthritisof thekneejoint,osteomyelitis,brucellosis,tuberculosis,viral infections, enteric infections, and subacutebacterialendocarditisareexamplesofkneepainwith an infectious aetiology (8). On physicalexamination, systemic symptoms and arthritissigns are generally present. In laboratory tests,acutephasereactantsarenoticeablyincreased.Inourpatient, kneepainof an infectiousaetiologywas not considered because arthritis signswerenot present, and the results of laboratory testswerenormal. Almost all connective tissue disorders,especiallyjuvenilerheumatoidarthritis,vasculitis,certain systemic diseases (such as rheumaticfever, lupus erythematosus, and familialMediterranean fever), leukaemia, lymphoma,andbone and soft-tissue tumoursmaymanifestas knee pain, leading to arthritis/arthralgia. Allofthesediseasesmaymanifestasmulti-systemicsymptoms that can easily bedistinguished fromother pathologies by physical examination,laboratory tests, and radiological studies (6).For our patient, infectious and rheumatologicaldiseases and malignancies were not consideredbecausethephysicalexamination,laboratorytestresults,andradiologicalresultswerenormal.

Childhood knee pain may be an indicatorof orthopaedicproblems involving theknee andsurrounding structures. Trauma is a commonlyencountered problem. Patient history andradiologicalimagingarehelpfulforthediagnosis.SLJ, OSS, patellar tendinitis, patellofemoralsyndrome,FPS, plica syndrome,LRP, and ITBSmay also cause knee pain. In these diseases,tendernessofthetendonoratitsattachmentsiteispresent,andpainoccursespeciallyduringsportiveactivities. Osteochondritis dissecans, meniscustear, ligament tear and chondral injuries alsocausekneepain (4). In thesediseases,generallya severe trauma has occurred, and symptomssuch as stiffness and locking of the knee occur.When these diseases are suspected, MRI mustbedonefordiagnosis.Ourpatienthadnohistoryoftrauma,hecouldnotlocalisethepainexactly,andpain occurredduring rest aswell as duringactivity. Because of the characteristics of thepain, the physical examination, and the normalradiological findings, orthopaedic problemsinvolvingkneewereruledout. Kneepainmayoriginatefromahippathology.Becausethekneejointisamoresuperficialjointthanthehipjoint,andbecausethenervesoftheanteriorkneeconsistofthearticularbranchesofthe femoral, common peroneal, and saphenousnerves, a painful and tender knee joint usuallyindicates an anomaly in the knee (7,9). Theaetiologyofpainreferredfromthehiptothekneemaybetheinnervationoftheanteriorbranchofthe obturator nerve or of the articular branchesof the femoral, commonperoneal,or saphenousnerves.However,painreferredfromhipmaybeperceivedaskneepain(10).Hippathologiesthatmay lead to knee pain include developmentaldysplasia of the hip, septic arthritis of the hip,sickle cell anaemia, SCFE, stress fractures ofthe hip and Legg–Calve–Perthes disease (4).Legg–Calve–Perthes disease—an idiopathicavascular necrosis/osteonecrosis of the femoralepiphysis—usually affects 4- to 10-year-oldsandpeaksbetween 5- and 7-year-olds.Childrenusually present with a limp or pain in the hip,thigh,orknee.Examinationofthekneeisnormal,but there is limited and painful rotation andabduction of the ipsilateral hip. Radiographsvarywith thestageof thediseasebutmayshowevidence of bone necrosis, fragmentation,reossification, or remodelling and healing (10).SCFE—displacement of the proximal femoralepiphysisoffofthefemoralneck—usuallyaffects11- to 14-year-olds, is more common in obesechildrenandboys, and is bilateral in20%–40%of cases (10). Anteroposterior (AP) and frog-leg

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radiographs of the hipmay showwidening andirregularity of the physis with posterior inferiordisplacement of the femoral head. On the APview,alinedrawnfromthesuperiorfemoralneck(Klein’sline)shouldintersectsomeportionofthefemoralhead(10). Intheliterature,2childhoodcasespresentingwith the complaint of knee pain resulting fromhippathologieshavebeen reported. In 1 case, a3-year-old child presented with pain localisedmedially on the left knee, as reported by VanOmmeren et al., and hip dislocation secondaryto traumawas found (11). Similarly,Meek et al.foundchondrolysisofthehipsecondarytosepticarthritis caused by Pseudomonas aeruginosa duringtheexaminationofachildwhopresentedwithkneepain(12).Inourpatient,recurrentkneepain was the reason for the visit to the doctor;an orthopaedic consultation was requestedbecausetheresultofthephysicalandlaboratoryexaminationswerenormal.Thekneepainofthepatient was related to the pathology of the hipjoint;MRIrevealedafocalcorticaldefectontheleft femoral head. The patient’s weight-bearingwas restricted to movements supported by theclutch, and his complaints were relieved. He isstillunderfollow-upforthehipjointpathology.

Conclusion

Childhood knee pain is a condition thatrequiresamultidisciplinaryapproach.Kneepainmayoriginatefromthekneeandthesurroundingtissues; however, itmay also be an indicator ofa systemic disease or an unrelated orthopaedicproblem. We conclude that examination of apatientcomplainingofkneepainisnotcompletewithouthipexamination.Wepresentedthiscaseto remind physicians that hip joint pathologiescan lead tokneepainandthat this factmustbeconsidered when evaluating the complaint ofknee pain, which is commonly encountered bypaediatricians.

Authors’ Contributions

Conceptionanddesign:AEYProvisionofpatients:MBAnalysisandinterpretationofthedata:HACriticalrevisionofthearticle:SKFinalapprovalofthearticle:TT

CorrespondenceDrAyseEsraYilmazMD(GaziUniversity)DepartmentofPediatricsFacultyofMedicine,FatihUniversityAlparslanTurkesCaddesiNo:5706510,Ankara,TurkeyPhone:+903122035555(Ext:5074)Fax:+903122213670Email:aysesra@yahoo.com

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