Cystic Lesions of BoneFIBROUS LESIONS OF BONEFibrous dysplasia - NO peri-osteal rxn or pain unless fxFx frequent but no pseudoarthro-sis, no ST componentElongated Diaphyseal lesion w "Ground Glass" matrixcentered in medullary cav, "al-phabet soup" of woven bonelucent, sclerotic, expasnsile, patchy, etc... MRI high T2Monostotic - #1 presentation, prox femur 78%, ribs, skullif in pelvis it will also be in ipsilat prox femurDiaphyseal if mild case, rarely affects spinePolyostotic - lesions usually larger, freq Cafe-Au-Lait"Sheperds Crook" femur & cystic pelvic lesions assocSkull base thickening, CN en-croachment, asym orbitsinvolvement of spine & soft tis-sue myxoma more common

#1 cause of Rib lesions, mostly lytic, well circuscribedslowly expanding & assoc w ex-trapleural massRegress w pubertyMalignant degeneration reported in <1%MRI - Hyper T2 unlike most fi-brous processesMalig degen to Osteosarc poss, esp w polyostotic form

McCune-Albright syn - polyos-totic fibrous dysplasiaFlorid disseminated form, usually unilat, female>maleassoc w cafe au lait spots and precocious puberty

Adamantinoma - appears simi-lar, mid tibia and jaw onlycan appear aggressive, 30+ yrs, trauma often assocmay be assoc w osteofibrous dysplasia, 15% met to lungs

Ossifying Fibroma - most in faceCortical based fibrous dysplasia w same ground glass appear-ancehomogeneous 1-5cm lesions, maxilla & frontal #1assoc w loosening of the teeth in mandiblePt <10yrs, vascularized fibrous stroma like FDNo alphabet soup of woven bone

Osteofibrous Dysplasia - fi-brous lesion of tibia & fibula in child <5yrspresent w unilat bowing & pain-less enlargement of the legtrabecula surrounded by osteo-blasts, mixed lytic Diaphyseal le-sionno osteoclasts as in fibrous dys-plasiaJuvenile Adamantinoma - possi-ble assoc

Congenital Multiple Fibroma-tosis - Infantile FibromatosisST fibromas diagnosed at birth, stabalize by 4mo, regress by 2yrsforms lytic lesion along metaphy-sis of long bones, variable size

Juvenile Fibroma - benign fi-brous tumors, cause pressure erosionscan be aggressive, high T2 in-tensity, freq recur after resectionJuvenile Aponeurotic Fibroma - subset w fibrochondral matrixoccurs in deep palmar facia of young malesST mass over wrist w stippled calc, bone errosion poss

Cortical Desmoid - Reactive re-pair at site of musc insertionfreq at adductor tubercle, "Don't Touch" lesion.

Desmoplastic Fibroma - aggre-sive expansile con tis lesionTibia #1, 10-20y/o, most benign or low grade malignancyresembles soft tissue desmoid, 50% recur P resectionNO ST mass, never metastisizeDDx Giant Cell, ABC or FibrosarcVery vascular, not easily distin-guished from FD

ENCHONDROMALucent defect w Ring & arc chondroid, 40-50Metaphyseal, unilat & solitary, never epiphysealNO periostitis, central, eccentric & expansileCartilage formed bones only, NO skull lesions#1 cystic lesion of phalanges, but no calc hereSim bone infarct but not well de-fined or serpiginousChondrosarcoma differs only in

its clinical pres - pain50% can degenerate to chondro-sarcoma, histo identicalDiaphyseal long bone lesions more likely to degSurgically excise, Bx is not a re-liable way to DDx

Ollier's Dz - mult enchondromas, NO inc in malig degPredominate Unilat, punctate calc remain distinctiveBizzarre bulbous expansions of tubular bones earlyColumnar growth of cartilage-nous tissue from epiBecome more rounded w older Pts, PathogLongitudinal striation - poss in long bone metaphysis

Maffucci's syn - mult enchon-dromas, Inc malig degHemangiomas assoc, phleboliths seen.

LANGERHANS CELL HISTIO-CYTOSIS - HISTIOCYTOSIS X

Birbeck Bodies - inclusions seen in cells on EMPenilaminar Organnels also as-soc50% have skin, eye, respiratory & fever w enlarged nodespts >2yrs w no organ dysfxn have 90% 5yr survivalwith organ dysfxn about 40% 5yr survivalTx - chemo reserved only for most severe cases

Eosinophilic Granuloma - Non-disseminated form, Bone only90% occur from 5-15yrs, 95% white, 2:1 male, 70% in flat bones, femur & humerus #1 long bones, 60% diaphyseal, rare in handscentral bony sequestrum like os-teomylitis & fibrosarc possMonostotic usually but #1 cause

of benign polyostoticPeriostitis freq, usually thick, wavy, & uniformFever poss similating osteo-myelitsSkull #1, Beveled NONSCLE-ROTIC edgesCalverial in 40%, often isolated parietal, mandible 20%present as painful enlarging skull mass, rarely into durahearing loss & otitis type sx if temporal bone involved Vertebra Plana - often effect post elements as well, neuro sx rare

Hand-schuller - Chronic Dis-seminated Histiocytosis, <5y/o Triad of destructive lesions, exophthalmos & diabetes insip-idusD. Insipidus II' to hypothalmus involvement, hyper T2 in pit stalk90% have cranial involvement, 15% have classic triadNO osteopenia or erosions, Re-

ticular nodular in lungs

Letterer-Siwe - Acute Dissemi-nated Histiocytosis, <1y/oFulminate - 95% die, often bone lesions don't formPermeative pattern sim to Ew-ings sarc possible.

OTHER CAUSES OF BENIGN CYSTIC LESIONSOsteoblastoma - rare, Giant os-teiod osteoma, >2cmExpansile bubbly lesion, Scle-rotic margins poss, sim ABCcan have speckled calc or even blastic in long bonesfreq in post spine, predominatly lytic here30% are vertebral, may cause cord compressionAppendicular are lytic w NO soft tissue mass

Osteoid Osteoma - not tumor or infection, unkown etiology

Cortically based sclerotic lesion w nidus <2cm, pt under 30Metaphyseal 75%, 2/3 around kneeMedulary - nidus in medula or joint less sclerosis seen, 20%Intrarticular - mimics synovitis, Sclerotic, joint eff seenPeriosteal - minimal sclerosis, cortical scalloping & ST swellingSpine - prefers appendages, freq cause of Scoliosisunilat pars Fx still a more freq cause thoughSpontaneous regression, NEVER seen over age 30Resection curative, recurrance due to incomplete resectionPain at night releived by aspirinNUCS - Double Density sign caused by hot nidusAngio - Nidus is hypervascular, rapid washoutMRI - shows nidus lying in region of marrow edemanidus enhances on both MRI &

CT, very vascularDDx - Osteomyelitis is always #1 in sclerotic lesion w nidusmay resemble sequestrum, can also mimic stress Fx

Aneurysmal Bone Cyst - must be expansile in pt under 30Tibia #1, 30% occur in assoc w a primary neoplasmDiaphyseal but usually near end, extend to metaphysisMarkedly destructive esp in pel-vic bonescan have densly sclerotic border, Fx freqCan sim OsteoblastomaSpine appendages often in-volved, lg soft tissue massPresent w pain, may follow truamaCT - can show multiple com-partments, fluid-fluid levels in 30%Can show rim enhancement w cent low atten

Solitary Bone Cyst - Must be central in a pt under 30simple or unicamiral cyst, ex-cluded if not central2/3 occur prox humerus, prox femur #2, any bone possNOT most commonly seen around knee unlike othersMetaphyseal, grows in from phy-sis, rarely epiphysealFallen fragment sign is pathag-nomonicAsymptomatic unless fx, triangu-lar in calcaneus Recur if packed too early

Hyperparathyroidism - HYPERcalemia, HYPOphos-phatemia Subperiosteal Resorbtion - radial aspect of dist phalanxdist clavicles, med prox tibia, & sacroilliac jointsosteopenia & cortical resorb of long bones late

Brown Tumors - flat bones & ribs #1, sim ABC, giant cellmost assoc w I' form, must have other HPT Sx as wellParathyroid Adenoma may cause tracheal deviationTx of HPT - all sx resolve, brown tumors scleros, resorbCalcitonin - has opposite effect as Parathyroid Hormonedecreases bone resorbtion, inc renal Ca+ clearancecauses Hypophosphatemia & Hypocalcemia

II' Hyperparathyroidism - Renal Osteodystrophy, more commonSoft tissue calc, Chondrocalcino-sis & Osteosclerosis MORE commonkidney can't hydroxylate 25-hydroxy to 1,25-dihydroxycholecalciferolcauses compensatory elev in parathyroid hormoneFreq cause of "Super Scan" w

MDP, only seen w 50% in I' HPTPhosphate retained, Ca+ low (Normal Ca+ 8.4-10.2, phos 2.2-4.5)

Chondroblastoma - must be Epiphyseal in a pt under 30Most occur at Knee, Calc fre-quently seen50% will have sm extention across the epi to metaphy70% assoc w periostitis in dia-phymetaphyseal region adjacentLytic & epiphyseal: 1) infection, 2) this, 3) giant cellEG and ABC also but very rare, mets & myeloma over 40consider subchondral cyst if joint DJD assoccarpal, tarsal bones, and patella behave like epihysisApophysis (ligamentous attach-ment) is similarMRI - often low T2 in child due to cellular nature

Chondromyxoid fibroma - men-tion w nonossifying fibromacan present w pain in any age, most in dist toe phalangeDiaphyseal w subendosteal thickening & scallopingUsually NO chondroid matrix, NO malig degenDifficult to distinguish from chon-droblastoma histologically

Cystic Angiomatosis - rare, as-soc w Osler-Weber-Rendu, asym when isolatedmult complex cystic lesions any-where, may spontaneously re-gress70% w viceral involvement have bad prognosis.

RARE CAUSES OF BENIGN LYTIC LESIONS1.Inclusion Cyst - follows trauma to dist digits mostlyEpidermoid lines cyst walls

2.Glomus Tumor - ST mass w destructive lesion, sharp margins Dist phalanges #1 esp in female, elsewhere in maleArise from glomeruli or pericytes in vessel wall

3. Hydatid Cyst - Dog tapeworm larvae, Pelvis & Spine #1 boneSharply demarcated & sclerotic margin, "bunch of grapes"can simulate an aggresive lytic process75% in liver, 15% lungs, freq calc in ST, 2% in boneSheep & human intermediate to dog (definitive host)

4. Primary Amyloidosis - can cause mult lytic bone lesions

seen in 15% w multiple mye-loma, preserves joint spaceosteopenia & rib lesions com-mon, NO subperiosteal resorbCourse trabeculation in hands poss, sim SLEProtenacious deposits in heart & GI #1, bone raremay calc in lung & kidneyplaque like deposits may be seen in synoviumII' Amyloidosis assoc w RA, ank spondylitis & others

5. Hemangioma - lytic w scle-rotic marg, esp in long bone head Spine or Calvaria #1, asym & solitary, pt >40y/oVertebral body - vertical linesCalvaria - honeycomb or sun-burst patternSoft tissue hemangiomas can cause errosions

6. Pigmented Villonodular

Synovitis -benign synovial swel-lingSubarticular erosions poss w joint pain & swellingLg subchondral cysts w NO joint space narrowing typicalCALC NEVER SEEN, no os-teoperosissee section on benign joint proc-esses

7. Sarcoid - 10%, lace-like de-struction in metaphsis of phalPeriosteal rxn & endosteal scle-rosis, NO errosions, penia

8. Intraosseus Ganglion - sub-chondral cytic lesionSharply defined sclerotic border, NO calc, NO ST portionDist Tibia #1, Talus #2, presents w pain in ankleSimulates a Geode, but no de-generative changesmucoid center, fibrous capsule in both

9. Acroosteolysis - dist pha-langes erroded awayScleroderma, frost-bite, burn, Hadju-Cheney.

MALIGNANT CAUSES OF WELL DEFINED LYTIC BONE LESIONSGiant Cell Tumor - 15% malig-nant, may recur even if not1. Epiphyses must be closed, but rare in elderly >50y/o2. Must abut the articular sur-face, knee #1, spine rare3. A sharp zone of trans w a nonsclerotic margin4. Must be eccentric, NO matrix calc, pathologic fx freqNonossifying Fibroma - must be under 30, MetaphysealFibroxanthoma - AFIP name, Whorls of fibrous tiss & Xanthoma CellsOccur in long bones, emanate from cortex

Knee #1, expansile w NO perios-titislytic w thin sclerotic border, slight scallopingFx poss esp if >2cm or occupy more than 50% of diaMRI - low T2 due to fibrous ma-trix20% of children, spont regres-sion w calc of matrix latesynonymous w fibrous cortical defect & FibroxanthomaInvolute by age 30, may be hot during this timeMultiple NOF - freq assoc w Neu-rofibromatosis

Metastatic disease - consider w any lesion IF pt over 40Hemopoetic marrow first, no X-ray evidence initiallyNO soft tissue mass, less peri-osteal Rxn than I' mass#1 site is lesser trochanter of fe-murany ca can be lytic, usually thy-

roid or renalRenal cell ca said to always be lyticSkull mets often lytic due to slow healingSclerosis results from slow growth allowing bone RxnCarcinoid & Hodgkins frequently scleroticBreast Mets - often imitate mult myeloma

Myeloma - Aggressive, bubbly lytic pattern esp in ribs#1 cause of extraplueral masses @40Plasmacytoma can occur in younger pt (over 35)Pelvis, thoracic & lumbar spine freq, skull rarecollapses vert body, appendages not involvedpreceed mult mye by 3-5 y

Childhood Mets - Horizontal ra-diolucent bands freqNeuroblastoma - freq lytic lesions esp in skullSutures spread from Inc intrac-ranial presPulm mets only late, Retinoblas-toma simLeukemia - 50% w Metaphyseal bands, less freq lyticBands probably II' to nutritional deficiet, not infiltationDiffuse periosteal Rxn & demin-eralizationDDx w blood: inc lymphoblasts vs inc catacholeaminesWilms does NOT met to bone, mostly pulmonary.

INFECTIONS

Pyogenic Osteomyelitis Chronic Sclerosing Osteomyelitis Brodie's abscess Septic Arthritis TB

Cystic Tuberculosis Syphilis Tabes dorsalis Actinomycosis Sporotrichosis Brucellosis Leporsy Salmonella Osteomyelitis Maternal Rubella Syndrome Septic Hip

CLASSIFICATION OF LYTIC BONE LESIONSUnder 30 lesions - EG, NOF, ABC, SBC, & ChondroblastomaNo Periostitis - Fibrous Dyspla-sia, Enchondroma, NOF, SBCEpiphyseal - Infection, Chondro, GCT, EG, mets & myelomaconsider subchondral cystABC diaphyseal but may ap-proach endMultiple - FEEMHISclerotic lesions - often regress-ing lytic lesions, under 30NOF, EG, SBC, ABC, chondro,

over 40 = metsosteiod osteoma, fibrous dyspla-sia, infection, brown tumors.

POSTTRAUMATIC LYTIC LE-SIONSMyositis ossificans - aggres-sive histology can mimic sar-comacircufrencial calc w lucent center pathognomonicCT shows best, can have peri-osteal rxnno ill-defined periph, or central calcbetween muscle fibers, not within

Avulsion injury - seen at inser-tion sites, delayed films helpCortical desmoid - prob an avul-sion of the medialsupracondylar ridge, periostitis poss, hot on nucoften occur in young people, histo can sim sarcoma

Subchondral cysts - geodes assoc w degenerative dzassoc w joint narrowing, sclero-sis, etcassoc w CPPD crystal dz, rheu-matoid, & avasc nec

Discogenic Vertebral Dz - a schmorl's node variantsclerosis of vert end plates, lytic or mixed possalways assoc w osteophytosis

Fracture - if not set can have exuberant callusPseudodislocation of the hu-merus - fx w hemarthrosisblood distends joint & displaces head inf, no dislocaxial veiw key to detection, can aspirate for blood

Tietze's Syn - costochodritis of the ribcauses bulbous painful swelling due to periostitis.

NORMAL VARIANTSDorsal Defect of the Patella - lytic defect in upper out quadmimics chondroblastoma, inf, or osteochondritis dissecan

Pseudocysts - paucity of trabe-cula at G tuberosity of Humerushyperimia II' to shoulder pain causing dissuseno sclerotic margin or wide zone of transitionalso seen in mid calcaneus, tuberosity of radius also

Os Odontoideum - unfused dens which may be post traumasmooth well corticated inf margin

Osteopoikilosis - mult sclerotic foci assoc w epiphysisfamilial bone islands, can mimic mets but no lytic proc.

Musculoskeletal InfectionsINFECTIONNO discriminating factors, scle-rotic border #1periostitis, soft tissue assoc, ex-pansile, all possibleif adj to articular surface cartilage loss & eff possBony Sequestra - seen w this, EG, and fibrosarcomaCrosses Disk like Gorham's Van-ishing Bone & Renal Osteodys-trophy

Pyogenic Osteomyelitis - 75% in kids, blood born staph aureus No anas between metaph & epi-phy plates at 2yrs to maturityMore vigorous periosteal rxn in kids due to lose periostMain cause of nec bone due to vasc disruption Soft tissue com-ponent seen at 2-3days, fat planes blurBone changes start after 10 days, Lg ST component assoc

Metaphysis #1, susceptability inc w size of boneNO joint involvementSequestrum - necrotic bone re-sidual, forms lateInvolucrum - Sheath enclosing sequestrumSkull - Hx of frontal sinus Dz, Trauma or mastoiditisMoth eaten pattern, no sequestraVertebral - usually involves end-plates, can cross Diskcollapses symetrically due to post element involvmentNo kyphosis as seen w TB, less extensiveParaspinous abcess freq compli-cation, LOOK FOR ITPenetrating injury & drug abuse #1 causesPseudomonas - seen in penetra-tion inj of footSalmonella - assoc w sickle cell, S. Aureus still #1Chronic Granulomatous Dz in Child - mult sites of osteomyelitis

bacteria are phagocytized but not properly killed

Chronic Sclerosing Osteomye-litis - often nearly sterileReactive process left over, lytic component variableLg ST component w breaks in cortexCartilage thinning & Juxtarticular osteoperosis assocSinus tracts freq - fibrosarcoma can develop in tractEpidermoid ca also seen in tract

Brodie's abscess - sclerotic sharp margins, freq periosteal RMetaphyseal - dist tibia #1, cavity in spongiosa, elongated along shaftfreq serpentine tracts to cortex, good for DDx from osteoid os-teomaIn-111 & Ga-67 less sensitive, detect acute osteomyelitis better Afebrile & pain free possible, rare

in spineSeptic Arthritis - cart errosion due to collagenase from leukocyteAutoimmune response to dam-aged cart, further resorptionFibrin deposits inhibit cart nutri-tion & metabolismTB - hematogenous spread to Metaphysis, extends to JointProgressive bone destruction & subarticular osteoperosisWell localized Abcess, Cold due to slow inflam processCasseating lesions - calcify, pa-thog when paraspinousSpine & Hip #1 - Always see muscle atrophyupper thoracic in kids, lower & lumbar in adultsKyphosis - errodes ant 1/3 of vert body, 90% anglepreserve post elementsNon-casseating types - M. Kansasei & ScrofulaceumCervical nodes mostly, rare bone involvement

Cystic Tuberculosis - Symetric long bone involvement in childMult well defined ovoid lytic le-sionsNO periosteal rxn except in late phase

Syphilis - bone changes w con-genital & III' aquired formsGumma - oseous necrosis which heals w fibrosis & inflamLytic lesions - Tibia, vomer & cal-varia #1, adj thickening freqcan cause lucency in diaphysis of any long boneTrophic lesions, symetric depos-its in periosteumCongenital form - exuberant pe-riostitis @ birthheal spontaneously or responds rapidly to PCNminimal soft tissue componentFragmentation & infarction of long bone metaphysisDDx scurvyTabes dorsalis -Gummatous de-

posits in cortex of ant tibthickening & increased density of any long bone possOnset at 20-30 y/o, pathogno-monic if bilatAssoc w neuropathic processAquired III' form - periosteal rxn less evidentClavicles - cortical & endosteal new boneCalvaria - Mixed lytic/sclerotic lesions ant & latNeuropathic lesions - in Lower ext & SpineII' to trauma, Tabes Dorsalis as-soc w thisCheck Serology - VDRL, Trepo-nemal Antibody

Actinomycosis - Anerobic G+ bacilli, permeative aggresive pat-tern#1 in thorax, spine & metaphysis of long bonesDoes not cross disk space, craniofacial form from tooth

Abdominal form starts in cecum or appendix - liver abcess"Mycetoma" - tumorlike ST swel-ling & draining sinusmost commonly seen in the foot following puncture wound

Sporotrichosis - fungus aquired from plants thru skin woundscauses septic arthritis & joint de-struction, lytic bone lesions possBrucellosis - causes exuberant "parrot beak" osteophytes of spine

Leprosy - 2 forms caused by mycobacterium lepraeLepromatous - 5% have bone changes, neuropathic typeNeural leprosy - 64% have bone destructionCystic lesions in fingers w II' sclerosis severe contracture or bone loss, not bothCalc in Radial or Ulnar nerve pa-thognomonic

Salmonella Osteomyelitis - esp in sickle cell child <2y/o

Maternal Rubella Syndrome - "Celery stick" around knee at 8molongitudinal metaphyseal bands, NO periostitis50% have PDA & hepatosple-nomegaly

Septic Hip - B strep in neonate, H. flu in infant, S. aureus in childpresent w fever and immobile joint, X-ray N initiallyEffusion displaces med aspect of head >1mm relative to oppositeAspirtation for Dx, Emergent ar-throtomy & open drainage for Txhigh risk of cartilage destruction, 15% assoc w head osteomyelitis.

Bone Forming Benign Lesions

1. Enostosis -Bone islands can mimic sclerotic met if >1cm1) oblong w axis along stress plane2) Well difined spicules extend to N bone along marginsMay grow very slowly, can have inc uptake on nucs Rare in chil-dren

2. Osteopoikiolosis - Small is-lands of compact bone, ASYMP-TOMATICinvolves spongy bone of epiphy-sis & metaphysis in long boneNO inc activity on bone scanImportant to surgeon due to inc Keloid formation

3. Osteopathia Striata - linear bands of sclerosis at metaphysisassoc w osteopoikiolosis, no inc uptake on nuc scan

4. Melorheostosis - Thickened & enlarged cortical boneHaversian canals present but abn, inc marrow cellularity"Candle Wax" excrescences along outer cortexPain, Contractures & limb short-ening occuroften in a single lower limbScleroderma like skin lesions poss over osseus lesionsBone scan intensly hot

5. Bone infarct - Always diaphy-sometaphyseal in long boneDense amorphic calc initially, lu-cent 10 days laterSclerotic "serpentine" border good for DDx from EGBenign type pereosteal rxn poss, permeative app possNO endosteal scalloping, NO cysts, NO malig transformationfreq underlying disorders - sickle cell, SLE, Gaucher'sPancreatitis, atherosclerosis,

EmboliMRI demonstrates a serpiginous sharp black borderPresents w Pain

Epiphyseal-metaphyseal Os-teonecrosis - infarct assoc w steroid usepossible due to microscopic em-boli from fatty liver or marrow ex-pansion

6. Juxtacortical Chondroma - arise between cortex & perios-teumMedial aspect of prox humerus, femur or tibia metaphysis NO contiguous marrow cav, Sauceri-zation of cortexvariable ST mass, sclerosis & periosteal Rxn - Dx w Bx

7. Osteochondroma - Osteocar-tilagenous Exostosis, to jointMost common benign neoplasm, rare malig transformation

MRI - shows intact low intensity cap on both T1 & T2Thicker the cap the more likely to transformArises from bone surface w hya-line cartilage capCortical & Marrow CONTINUITY key to Dx, away from epi30% on femur, Sx due to size, often lobulatedSpine - can cause scoliosis, grow into canalSessile form can sim Juxtacorti-cal chondroma on humerusAquired II' to truama alsoSubungual Exostosis - assoc w trauma to fingers

Trevor's Dz - Osteochondroma in joint, swell & deform, unilat

Hereditary Multiple Exostoses - Auto dom, seen youngerVariable severity, may be asym, 20% malig transformationBowing deformities, shortened

bones, Madelung wrist deformity

8. Osteoid Osteoma - not tumor or infection, unkown etiologyCortically based sclerotic lesion <2cm, pt under 30Nidus within a small central lu-cency, 2/3 around kneeif nidus in medula or joint less sclerosis seen, 20%joint eff if lesion intracapsularif nidus in periosteum see perios-titis like maligmay resemble sequestrum or disappear if calcifiesSpine - prefers appendages, FREQ painful ScoliosisDDx - Brodies Abcess #1 in scle-rotic lesion w nidususe Bone scan, Double Density sign due to nidusNORMAL VARIANTS

Dorsal Defect of the Patella - lytic defect in upper out quadmimics chondroblastoma, inf, or

osteochondritis dissecan

Pseudocysts - paucity of trabe-cula at G tuberosity of Humerushyperimia II' t MRI - shows NO ST componentSpontaneous regression, NEVER seen over age 30Resection curative, NO malig-nant potentialPain at night releived by aspirin

9. Osteoblastoma - rare, Giant osteiod osteoma, >2cmExpansile bubbly lesion, Scle-rotic margins poss, sim ABCcan have speckled calcUsually in post elements of spine, NO soft tissue massCan recur but more likely to be osteosarcoma 2nd timemore lace like osteoid matrix seen

10. Osteoma - slow growing be-nign tumor of sinuses & cranium

protruding mass of dense bone, usually incidentalcan cause sinusitus, HA or exophthalmos if lgArises from cortex, freq no ha-versian sysMultiple Osteomas assoc w Gar-dener's Synpolyposis, dental lestions, des-moids & seb cysts also.

Malignant Bone TumorsDIFFERENTIATING MALIG-NANT FROM BENIGN1) Zone of transition - most re-liable, seen w every lesionNarrow - benign w few excep-tionsthis includes sclerotic marginsWide - aggresive, usually be-cause they are fast actingPermeative - multiple sm holes w no clear borderRound cell tumors - m myeloma, reticulum cell sarc

EG, Bone infarct & infection oc-casionally

2) Cortical Destruction - can be missleading alonecortex replaced by benign fibrous or chondroid matrixinfection, & EG also cause thisgiant cell tumor & ABC can thin cortex so not seen

3) Periostitis - II' to irritation, very nonspecific patternsbenign - thick wavy formation, EG or inf may be aggaggresive - lamellated, amor-phous, or sunburstCodman's triangle often seen at leading edgecan not thicken if malignantmay thicken in late stages of healing if benign

4) Axis of orientation - unreli-ablebenign - in long axis of long bone

Ewing's sarcoma is a clear ex-ceptionmalignant - round lesionsfibrous cortical defects are often round however

5) Arteriography - helps define ST vs bone involvementDemonstrate Neovascularity - pathognomonic of maligArterial cutoffs & Venous lakesGuide Bx away from necrotic re-gionsAGE GROUPS1-30) Ewing' sarcoma, Osteosar-coma30-40) parosteal sarcoma, Fibro-sarcoma, Malignant giant cellReticulum cell sarcoma (primary lymphoma of bone)40+) Mets, Myeloma, Chondro-sarcoma

PATIENTS 1-30 YEARS OLDEwing's Sarcoma - Mysenchy-mal prolif from marrow, 5-30y/o

Major Long Bones - #1 in child, Permeative & Diaphyseal50% in flat bones - more com-mon in adolescentsNO bone or cart formation, freq hem & necFreq periostitis, Onion skin #1, causes bone thickeningST component in 90% - more freq & larger than osteosarcPainful, severe systemic Sx early in Dz30% present w Mets - Lung #1, skeletal #2DDx - Reticulum cell & neuro-blastoma mets simEG or infection more likely if thick periostitis

Intramedullary Osteosarcoma - #1 primary bone tumor, 2:1 maleMetaphyseal 80%, diaphyseal 10%, 75% occur around kneeepiphyseal very rare, flat bones 10%Destructive w freq reactive scle-

rosis, breakout from medST component freq, cumulus cloud of calcified osteoid75% cross epiphysis & joint, 20% w intramedullary skipsDiaphyseal form often present w Fx, bad prognosisMRI - evaluate ST component, encroachment on joint, vascPulmonary mets assoc w Pneu-mothorax, skeletal mets rarePain & elevated alk phos, Assoc w Pagets Dz

Well-Differentiated Osteosar-coma - #1 at dist femurhisto similar to low-grade pa-rosteal osteosarcomasimulates desmoplastic fibroma

Telangiectatic osteosarcoma - lytic only, better prognosis, sim ABCsmall areas of osteoid key to Dx, smaller tumor load

Osteosarcomatosis - multifocal w very bad prognosis

Burkitts Lymphoma - Sim ew-ings or reticulum cell in childassoc w CMV virus, good sur-vival

Rhabdomyosarcoma - present at 5yrs, 50% head & neck, pelvis #2freq mets to lung, nodes & liver, one in 20% but rare direct exten-tion

PATIENTS 30-40 YEARS OLDParosteal Osteosarcoma - less deadly, extracortical bone depOriginates form the periosteum & grows outside the boneonce cortex is penetrated it is a central osteosarcST calc with a central distribution in the massPostmed dist femur #1 at site of adductor insertion

imitates a cortical desmoid (avul)benign avul inj can appear very maligDense Centrally w cleavage plane between it & cortexCauliflower like, may not see conection to cortex** DDx - Myositis ossificans can imitate but dense peripherally

Periosteal Osteosarc - cotical, no medul invasion, rareSaucerized cortex, intense peri-osteal RxnPoorly diferentiated, predomi-nately Chondroblasticprognosis better than intramedul-lary osteosarcoma

Gnathic Osteosarcoma - older pts, less aggressive

Fibrosarcoma of Bone - usually pure lytic, variable aggresiveExpansile in medullary cavity, freq associated calc

Sequestrum poss, NO periosteal rxn, NO ST mass#1 around knee, Diaphyseal every where else

Malignant Fibrous Histiocy-toma - same appearance, see ST

Desmoid - low grade, usually well defined, slow growingbenign periostitis w thick spic-ules, thick septano met, but extensive local inva-sion

Periosteal Fibrosarcoma - in-vades cortex, medullary II'Fibrosarcoma of Soft Tissue - in-vade bone II'

Malignant Giant Cell Tumor - 15% are malig, primarily 30-40Dx w recurrance, or met to lungshistology is identical to benign variaty

subarticular, closed epiphysis, eccentric, sharp zone

Reticulum Cell Sarcoma - I' lymphoma of bone, male 2:1Permeative pattern identical to ewings sarc#1 around knee & prox tibia, Rarely expansilecan involve a lg amt of bone w no sytemic symptomsI' Hodgkins & Lymphosarcoma are variants, very rareHemagiopericytoma - rare vasc tumor, benign or maligLytic & expansile but permeating pattern possHisto sim to Glomus Tumor

Chordoma - 55% sacroiliac, 25% clivus, 20% cerv spine esp C2Grossly expanding, highly ag-gressive w lg ST massSlow growing, met late w NO skeletal met, fatal.

PATIENT OVER 40Metastatic Disease - include in any DDx if pt over 40Pain presents in 60%, Fx if >2cm or >50% of diaHypercalcemia - mets #1 cause in hosp ptsHypertrophic Osteoarthropathy - Lung #1, mesotheliomaSclerotic multiple foci #1 for breast and prostateHodgkins - the only lymphoma w sclerotic metsIvory Vertebra - Paget's #1, mets & Hodkin's #2Prostate also presents w freq pe-riosteal rxnRenal Cell Ca - 90% Blown out lytic expansion 25% present w mets, NO calc, Periosteal RxnThyroid - Lytic, 8% present w bone metsLung - 80% lytic, more often blastic if sm cell, 15% w boneLymphoma - NHL can be I', 75%

lytic & metaphysealcan be aggressive, Perosteal rxn, ST mass & path Fx in 25%Hodgkin's - always met, assoc w sclerosis & Ivory VertNeuroblastoma - Permeative metaphyseal lesion, periosteal Rxnoften symetric & sim Ewing's, leukemia or osteomyelitis

Myeloma - Aggressive, bubbly lytic pattern esp in ribsPlasma cell prolif in red marrow, edosteal errosionPolyneuropathy, Organomeg, Enocrine, M-protien, Skin#1 cause of extraplueral masses @40Pelvis, thoracic & lumbar spine freq, skull rarecollapses vert body, effects mar-row not post elementsDiffuse Form - Osteoporosis #1 presentation, rarely scleroticBone Survey nît nuc scan

Plasmacytoma - presents 10yrs younger (over 35)preceed mult mye by 3-5 yChondrosarcoma - Intramedul-lary type #1, geographic permea-tiveLg lytic component, ring & arc chondroid matrix#1 in prox long bones, aggresive w flat boneST mass is large, slower growing than osteosarcomalung mets #1, skeletal rareAssoc w Enchondroma, Osteo-chondroma & PagetsLow grade lesions indistinguish-able even w pathAlso sim Bone InfarctsST component is key to DDx from enchondromaAlways presents w PAIN, en-chondroma may notLidocaine in joint stops DJD pain, not lesion painhotter than ant iliac crest on

nucs, enchondroma notSelenium75 - good for ID of tu-mors w cart matrixFreq cartilaginous lesion of ant ribs in adults

Periosteal Chondrosarcoma - larger ST mass, no medulary compsim periosteal chondroma or sessile osteochondroma

Clear Cell Chondrosarcoma - less aggresive w sclerotic rimPresent 30-40, improved prog-nosis, can be totally lyticEpiphyseal & often confused w a chondroblastoma MRI - very high T2

Mesenchymal Chondrosar-coma - Very aggresive, lg ST componentPresent 20-30, often assoc w prev intrmedullary chondrosarcCan be pure ST, multifocal is-

lands of malig cartilageMyxoid type - also pure ST, poor prognosis, avg 50yrs

Benign Causes of Periosteal Elevation

1. Hypertrophic Pulmonary Os-teoarthropathy - clubbingSubperiosteal new bone, Meta-physis only, NO epiphysealCaused by pulm mass, I' bone or met, Benign cause poss

2. Familial Pachydermoperios-tosis - assoc w clubbing

3. Caffey's Dz - Infantil Cortical Hyperostosis, before 6mo ST swelling, Immature laminar bone adjacent to cortexEtiology may be viral

4. Scurvy - Subperiosteal Hem-orrage in healing phase, P 6mo

5. Sarcoid - Elevated phalangeal lytic lesions, Endosteal sclerosis

Soft Tissue DiseaseMALIGNANT SOFT TISSUE TUMORS1. Malignant Fibrous Histiocy-toma - #1 malig ST tumor, 40-70Presents as painless soft tis mass >5cm3 cell types, spindles predomi-nate, histiocytesGiant cells also poss, malig or benignPoorly defined calc, poss in-volvement of adj boneCan cause scalloping of outer cortex of adj boneOsseous MFH rare - geographic lytic lesionsNo periosteal rxn or sclerosisClosely related to fibrosarcoma, identical appDDx - Liposarcoma, but no fat present in MFH

Synovial Sarcoma can also cause scalloping

2. Liposarcoma - #2 ST mass, presents at 40-60yrs, rare in child Extremities & retroperitoneum, 5-10yrs earlier in extremitiesLow Grade - well differentiated, cannot met, local recursynonymous w Atypical Lipoma, ALWAYS has fatretroperitoneal form assoc w freq recur, bowel obs & deathMyxoid Type - most common, 50% have visible fat by CTMRI - benign cyst like app poss, freq assoc hemRound Cell Type - poorly diff hy-percellular formDedifferentiated Liposarcoma - refers to mixed types

3. Fibromatosis - Extraabd Desmoid of deep & superficial tissues

In general the deeper the growth, the worse the prognosisShoulder #1, errodes outer cor-tex of bone if deepAggressive Infantile Type - dis-covered before 2yrsno met but locally aggresive & recursAll are very vasc w intense en-hancement, NO necrosis

Dupuytrens Contracture - Pal-mar Fibromatosis, ulnar sideIf removed while cellular will re-cur, wait until fibrosed

Infantile Myofibromatosis - Myoblastic & fibroblastic lesionBone lesions common, poor prognosis if mult & deep

4. Synovioma - Synovial sar-coma, predominatly a spheroid ST mass#1 at knee, hands & feet alsoOriginate from tendon sheath,

rarely assoc w jointjoint masses are not maligCalc 30%, Bone errosion freq, occur up to 2cm from joint

BENIGN SOFT TISSUE TU-MORS1. Lipoma - Mature fat in 40-60y/o, female predominance 95% solitary, Tumor fat not avail-able for metabolismCT - -65 to -120HU mass, well circ w NO enhancementthin fibrous strands poss, if ex-tensive think fibrosarc

Neural Fibrolipoma - aka lipo-matous hamartoma of median nerveMost in young adults, present w pain & paresthesiaMacrodactly - freq in 2nd or 3rd digit

Lipoblastoma - cellular imma-ture lipoma, infants before 3yrs

Superficial ST & extremitiesCT - sim liposarcoma but not seen in young pts

Angiolipoma - encapsulated w vasc stroma & fibrin, young adultsrare infiltrating form seen w no capsule, hemangioma like

Lipomatosis - diffuse over-growth of mature adipose tissuepresents before 2yrs, often in foot or handbony hypertrophy freq, nerve not affected

Hibernoma - brown fat lipoma, extremely vascular on angiooccur in young adults, scapula & axillary region #1extremely rare in pure form

2. Hemangiomas - Benign Vasc neoplasm, fibrous tiss & Fat freqPlain Film - ST mass w assoc

cortical holes posscortex remains intact unlike per-meative round cell procPhlebliths often assocMRI - flow voids, Lace like pat-tern of FAT in interstitiumCavernous hemangiomas often larger w less nonvasc tissue

3. Elastofibroma - Benign RE-ACTIVE tumor like lesion of chestComma shaped mass under scapula & chest wall in elderly ptII' to mechanical friction, usually asym, freq bilat

4. Synovial osteochondroma-tosis - benign synovial metepla-sia mult loose calc bodies in joint pa-thognomonicloose bodies not always calc, mimics villonodular synerosions of the acetabulum may be seen

5. Pigmented Villonodular Synovitis - benign synovial swellingSubarticular errosions w Joint swelling & painLg subchondral cysts w NO joint space narrowing typicalCALC NEVER SEEN assoc w this process, NO osteoperosissee section on benign joint proc-esses

6. Baker's Cyst - synovial cyst between semitend & med gas-troc mMRI will show fluid, II' to med meniscus tear

7. Tumoral Calcinosis - mult calc deposits near major jointsEtiology unknown, occurs in young blacksMultilobular & Cystic, Milky Ca+ phosphate fluid present

8. Radiation Myositis - T1 im-ages show N fibrofatty septationsT2 shows inc signal due to in-flama etc

9. Thickening of Heal Pad - seen w corticosteroid excess, Cushingsalso seen w acromegaly, abn if >21mm

SOFT TISSUE CALCIFICTA-TION1. Myosistis Ossificans - Trauma, rim of cortical bone

2. Dermatomyositis - Collagen vasc Dz, linear & confluent ST Ca+Hands, Axilla, Inguinal & chest wall most freqLymphadenopathy, Spe-nomegaly, Rash & eventual deathatony & dilation of esophagusDDx scleroderma & RA - bony

changes sim but less markedJoint contracture, but NO termi-nal tuft resorbtionAssoc w malig, genital Ca in fe-malesNO assoc elevation in serum calcium levelsJuvenile form - most resolve spontaneously, 40% mortality w/o Tx

3. Scleroderma - Fluffy calcific depositsCalcinosis Cutis - from tight over-lying skinDist phalangeal resorbtion, Pen-ciling & Autoamputation

4. Werners Syndrome - Osteo-porosis, ST Atrophy & CalcNeuropathic changes & DJDPremature ageing, short stature & arteriosclerotic probs

5. Leporsy - Calcifiction in Nerves only

Metabolic Bone DiseaseOSTEOPENIAOsteoporosis - diminished bone quantity in otherwise N boneAging - 95%, postmenopausal femalesSteroids - Exogenous more common than Cushing'salso assoc w exuberant callus formationPlain Film - Cortical thinning #1 sign, middiaphysis 2nd metacarpPermeative Pattern - can result from dissuse, sim Ewingcortex riddled w holes, Ewing originates in medullarythin transverse trabeculae & ac-centuated vertical trabeculaeNo assoc lab abnormality, elev of urine hydroxyproline poss

Pseudopermeative pattern in cor-tex has 2 other causesHemangioma - hyperemia II' to inc flow & tunneling

Radiotherapy - usually lg holes but can be small

Osteomalacia - due to defect in Vitamin D metabolismDietary, Absorbtion problem, Liver Dz or Renal Dzexcess nonmineralized osteoid, always assoc w bone painProminent trabeculae replace normal small structural typeLooser's Zones - unmineralized osteoid seam on concave side

Renal Osteodystrophy - #1, fails to convert 25-OH-D3 to 1,25-OH-D32 mechanisms contribute to as-soc osteopenia - Vit D prob & II' HPTRenal tubular dysfxn causes Vit D resistant typeFanconi Syn - tubules spill phos-phateGlomerular Dz - Retain phos-phate causing dec Ca+

II' hyperparathyroidism induced by dec Ca+ levelCa+ Def & hyper or hypophos-phatemia assocChanges of HPT more common in older pt rather than ricketsDietary - Inadequate Vit D intake, rare before 1y/oDefective fat uptake - prevents transport of Vit DSprue or defective bile saltsLiver - fails to convert vit D to 25 OH cholecalciferolHepatic Osteodystrophy - seen in alcoholics

Ricket's - Osteomalacia in an immature skeletonCartilage fails to mature in en-chondral bone growthLoss of zone of provisional calci-fication, Dist femur #1Inc space between metaphysis & epiphysis, wide physisCartilage overgrows in long & lat dimensions

Flared irreg epiphysis, Metaphy cupping, diaphy bowSquared & flattened post calvar-ium, basilar invagPeriosteal elev, pain, coarse tra-becRachitic Rosary - overgrowth of cart in ant ribs & wristLooser's Fx - poorly mineralized bone laid w remodeling

Hypophosphatemia - Inherited defect in alkaline phosphatase activityextracelluar accumulation of in-organic phosphate causes os-teomalaciaSx - same as rickets, symptoms can improve with maturationAdult form - 50% have slow on-set with no childhood DzST calcification seen in all forms but most pronounced in adultEnthesopathy - prominent bone spurs at tendinous insertionsCPPD arthropathy freq, indistin-

guishable from idiopathic typeInfantile Form - always lethal, NO ossification of skull, AUNT MIN-NIE

X-Linked Hypophosphatemia - previously called vit D resistant ricketsProximal tubules fail to resorb filtered phosphateOsteomalacia & insufficiency Fx common, presents after 1st yearPeriosteal Hyperostosis freq, ac-tually see inc bone mass in adultsEnthesopathy - bone formation at liagament & tendon attachment freqDefective dentin formation causes freq tooth problems

Non-Hereditary Hypophos-phatemia - oncogenic osteomal-ciamost commonly due to mesen-chymal tumor

HyperparathyroidismPrimary Hyperparathyroidism90% Adenomas, 10% hyperpla-sia or mult glandsOsteoblasts stimulated to mobi-lize Ca+ from boneHYPERcalcemia results & causes HYPOphosphatemiaSubperiosteal Bone Resorbtion - pathognomonicRadial aspect of mid phalanges of 2nd & 3rd finger #1can prog to spiculation & com-plete cortical resorbJuxta-articular errosions - pubic syph & sternoclavicSubchondral Bone Resorbtion - involves axial skeletonosteoclastic resorbtion of trabe-culae beneath cartMicrofractures result & can cause collapseBrown Tumors - characteristic of I' but seen w II' alsoFibrous Tis & Giant cells replace

bone, expansileMay become sclerotic after Tx of HPTOsteosclerosis - mostly in II', in-volves axial skeleton"Salt & Pepper" skull - Trabecular Resorb & scleros"Rugger Jersey" Spine - Sub-chondral bone sclerosisChondrocalcinosis - CPPD oc-curs in 40% of pts w I' HPTLigamentous laxity - atrophy of ligament & attachmentSeen best at syph pubis & SI, joints supported by ST

Renal Osteodystrophy - Sec-ondary HyperparathyroidismPhosphate retained, Ca+ dropsHYPOcalcemia due to HYPER-phosphatemiaLow Ca+ causes hyperplasia of Cheif Cells in ParathyroidN Vit D metabolism disrupted causing osteomalacia alsoChildren - usually caused by

congenital renal malformAdults - urinary tract obs or chronic pyelonephritisleads to glomerular failure & phosphate retentionOsteosclerosis more freq, Chon-drocalcinosis less than I'"Tumoral Calc" - extensive ST calc, more freq than I'Hyperuricemia can also result causing II' Gout

Scurvy - Impaired Osteoid For-mation, ST Ca+ phos deposites Metaphyseal - Dense calc of metaphysis w prox zone of attri-tionTrummerfield zone w the white line of FrankelPelkin's Fractures - Corner Fx of brittle metaphysis freqPeriostitis due to subperiosteal bleedingNever seen before 6mo, mater-nal Vit C protective

Vinyl Chloride Exposure - Tuft resorbtion & SI ankylosisReturns to N after exposure stopped

OSTEOSCLEROSISR) Renal Osteodystrophy - or any cause of HPT, but this #1Subperiosteal bone resorb #1 sign10-20% have sclerosis, etiology unkown

S) Sickle Cell Dz - sm percent-age for unknown reasonassoc w bone infarcts & vert end plate step-offs

M) Myelofibrosis - myeloprolif-erative syn, prog marrow fibrosis in pt over 50Anemia causes extramedullary hematopoesis & lg spleenAssoc w Mets, Poisoning, chronic inf, AML, McCune-Albright

O) Osteopetrosis - generalized dense amorphous boneN trabecular structure obliter-ated, NORMAL MANDIBLEDefective Osteoclasts - fine I' spicules persistmedulla filled, die from anemia & infectiondenser prox due to greater growth proxgrowth spurts cause lucent bands clasts keep only during slow growthInfantile Form - CN compression, throbocytopenia, deathAdult Form - 50% asym, recur-rent trans Fx II' to brittleCN foramen narrow, mastoid air cells obliteratedErlenmeyer Flask long bones -clublike & flarring endLongitudinal metaphyseal stria-tionsend plate fibrosis, sandwich vert

P) Pyknodystosis - Toulouse-Lautrec Syn, an artist w the Dz Auto Dom, short w HYPOPLAS-TIC MANDIBLE Dense pointed dist phal pathag-nomonic, 2:1 maleSutures spread & persistent wormian bones seen

M) Metastatic Ca - prostate & breast #1, Hodgkins alsoassoc w cortical destruction or lytic lesions

M) Mastocytosis - Mast cell ac-cum in mult organs, 50% occur at <6moUticaria Pigmentosa- skin rash is #1 Sx, 90%assoc w LUEKEMIA, pancy-topenia, hepatomeg, lymphade-nopathyHematopoetic marrow process, X-ray detectable in 70%Trabecula Thickened from me-

dullary side, Axial skeleton I'Scattered sharp sclerotic foci, areas of rarefacationassoc w thickened sm bowel folds, bone pain seen in <30%

P) Paget's Dz - rarely diffuse, 20% monostotic, any bone can be affectedBone ENLARGEMENT & cortical thickening, 3 phasesOsteolytic, Sclerotic bone forma-tion & MixedII' bone has no haversian sys, Fx & avulse easilyThickened haphazard trabecula, freq bowingProg end to center w Flame shape, Tibia only exeptionFibula never involved"Banana fractures" & partial frac-tures on convex sideSLOW progression, rapid changes considered malig de-generationPelvis - Ileopectineal line must

be thickenedMedial migration of femoral head poss, sim RASkull - Osteoperosis Circum-scripta, early lytic process"Cotton-wool" Thickening & En-largement, blastic phaseImpingement of Cranial Nerves assocBasilar Invagination, no inc ICP assocSpine - Dense picture frame vert, appendages involvedSymetric collapse poss, "vertebra plana", sim EGStriations may mimic heman-gioma but usually scleroticSarcomatous Degeneration - <1%, to Osteo, chondro or fibroundiff w elements of all 3 freq, osteo #1Only time Sarcomas of Skull oc-curGiant Cell Ca - Only time they occur in older pt'sALL occur in the skull & facial

bonesTumors more likely to metasta-sizeNucs - marked uptake w active blasticNeoplasm - cold on bone scan, hot on galliumMRI - not indicated, inc fat inten-sity on T1LAB - Increased Alkaline Phos-phatase levelsInc Ca+ causes renal calculi & NephrocalcinosisUrinary hydroxyproline levels also incHigh output cardiac failure due to mult tiny AVM's

A) Atheletes - II' to inc stress

F) Flourosis - II' to dietary in-take, rareassoc w ligamentous calcifica-tion, esp sacrotuberous

OTHER CAUSES OF DENSE BONESHypervitamanosis A - Cortical thickening of Tubular bonesDiaphyseal & symetric, diffuse periosteal RxnNO subperiosteal hem seen, NO mandibular involvementMetaphyseal spurring & In-creased ICPAssoc w itching, dec appetite, hard tender lumps on extHepatosplenomegaly, anorexia, alopecianever seen under 1y/oDDx - Ricketts, Caffey's, Syphil-lis, healing Scurvy

Hypervitaminosis D - affects adults & children oppositeChild - Thickening of provisional zone of calc & CortexAdult - Osteoporosis & tumoral ST calc esp at joints

Hyperphosphatemia - "Juvenile

Paget's Dz", auto rec in Puerto Rican'sFusiform expansion of Spongiosa, no normal maturationDwarfism, bowed bones, wide irreg epiphysis sim to ricketsSkull enlarged w Sclerotic patches, Cranial Nerve deficitsBiconcave vert bodies, Cystic le-sions poss

Hypoparathyroidism - HY-POcalcemia & resulting neuro-musc SxParathyroid defeciency - usually II' type, IatrogenicOsteosclerosis & calveral thick-ening is I' manifestationBasal Ganglia & SubQ tissue calc also

Pseudohypoparathyroidism - end organ resistanceCharacteristic short stature, round face, obesity & MR resultHypocalcemia & Hyperphos-

phatemia but elevated PTH level

Pseudopseudohypoparathy-roidism - clinical syndrome, NORMAL labs

Cushings - Axial Osteoporosis #1, 3:1 female Assoc w adrenal hyperplasia in adults Vertebra - Prom vertical stria-tions, Dense cupped endplatesFx's heal w excessive callus (esp RIBS), mult bone infarctsCalveria stippled, demineralized sellaAdrenal tumors in children - de-layed skeletal maturation

Thyroid Acropachy - periosteal rxn & thickening of tubular bonesfuzy periostitis on radial side of metacarpals & mid phalanges very distinctivePresent HYPO or euthyroid w exopthalmos & pretibial edema

occurs years after Tx for hyper-thyroidism

Cretinism - Hypothryoid from birth, Delayed Skeletal matura-tionEndosteal cortical thickening obliterating marrow cavityIrreg ossifacation esp in femoral epiphysisVert bodies flat & hypoplastic, esp T12-L1 causing KYPHOSIS

Acromegaly - Eosinophilic Ade-noma #1 cause, equal in sexes50% show Skull thickening esp at base, 20% w N sellaPeriosteal Apositional bone for-mation in long bonesExagerated tuberosities, general-ized ST thickening, esp heal pad to >21mmPremature Oteoarthritis - carti-lage thickens then diesdue to inadequate blood supply, post vert scalloping

Vert - post scalloping in 30%Enthesopathy - "Spade Digits" & lg spurs of distal metacarpals

Post Radiation Tx - Pattern matches ports, ST calc assoc

Worth Syndrome - Auto Dom, Endosteal HyperostosisEndosteal thickening of tubular bones obliterating marroOsteosclerosis of skull begins at base, extends to faceMandible freq involved, pelvis & ribs not involvedSpine - primarily post elements thickened

Lead Poisoning - can create dense metaphyseal lineabnormal remodeling of tubular bones possiblewidened cranial sutures due to inc intracranial pressure possible

Englemann' Dz - Progressive

Diaphyseal Dysplasia, not famil-ialRapid prolif of new cortical bone, symetrical thickeningSim paget's but Diaphyseal only, stops at metaphyseal line

Pachydermoperiostosis - Hy-pertrophic Oteoarthopathy, Auto DomM>>F, middle age, lg thick skin folds, enlarged paranasal si-nusesIrreg periosteal proif of phalnges & dist long bones - CLUBBINGEpiphysis & metphyseal regions of tubular long bones #1cortex thickens but NO narrowing of medullary cavitycan have acro-osteolysis, pro-gression ceases after several yearsDDx - pulm osteoarthropathy (painful) & thyroid acropachy

Osteitis Condensans of the

Clavicle - thickend trabecula due to stressnormal joint space maintained, clavicle head may be expandedincreased density confined to lower medial clavicle, UNILATpain & swelling but no skin in-flammation

Congenital Bone DiseaseCONGENITAL BONE DIS-EASESSubperiosteal new bone can be seen in N infants

Scoliosis - Adolescent type most common, multifactorial inheri-tanceCongenital Scoliosis - look for assoc vert body anomalies, hemi or butterflyIdiopathic Scoliosis - usually convex to the right, L assoc w other anomali15% assoc w congenital heart Dz

Wedged vert body at apex of curve, I' curve forms w II' curves above & below8:1 female, starts P 10y/o & stops w cessation of growthNF-1, TB, Osteoid Osteoma, Marfan'sWilm's - due to radiation necrosis of ipsilateral apophysis

Infantile Cortical Hyperostosis - marked cortical thickening <6mo old, acutlely ill, irritable - probably infectiousMetaphysis spared, Freq exac-erbation & remissionresolves completely within a few monthsVert bodies also spared

Osteogenesis Imperfecta - bad osteoblasts, poor osteogenesis Collagen also abn, Fibroblast cultures for DxTarda - (Types I), Auto Dom,

BLUE Sclera, least severe formNO congenital fractures but Rib-bon Ribs & DeafnessLong bones - Diaphyseal Bow-ing, Cyst-like lesionsSkull - Wormian bones ALWAYS seen, Basilar InvaginationFx freq w Exuberant callus for-mation, NO IUGR by USNo further fx usually occur P pu-berty"Popcorn" metaphysis - cystic le-sions pathog for OIType IV - similar but mild deaf & bowing, No blue scleraCongenita - (Types II & III), Auto Rec, accordian bones, II lethalThin skull Wedge or bow-tie vert bodies

Pseudohypoparathyroidism - End organ resistance to hormoneHeritable syndrome w 3 compo-nents1) Skeletal abn - Manifestations of HYPOparathyroidism

Osteosclerosis, Calverial thicken-ingDwarfism - Shortened & bowed long bonesShortened 4th & 5th metacarpals & distal thumb phalanx2) Soft Tissue Calc - Basal Gan-glia, Dentate nuc, skin & subQBroad Facies, Mental Retarda-tion & Cataracts also assoc3) Abn Blood Chemistry - LOW Ca+, HIGH phosTurner's Syndrome - XO, De-layed epiphyseal fusionShortened 4th & 5th metacar-pals, Shortened ulna"Drumstick" metacarpals & pha-langesCubitus Valgus - large medial femoral condyleOdontoid hypoplasia & small sella tursica"Squared" vertebra - shortened A-P diameterHorseshoe Kidney, Coarctation of the aorta & Infantilism

Syphilis - Trophic depostits of endochondral boneZone of provisional Calc widens, lucent fibrous zone prox"Saber shin" - severe form of subperiosteal bone growthoccurs everywhere but ant tibia most commonCharcot joints & minimal ST component, rapid response to PCNDDx - scurvy & ricketts, but pt too young

Hereditary Osteocartilaginous Exostoses - effects long bonesexostoses are not as large or spike-like as isolated formMadelung deformity of wrist - Paired bones show dif growthSupernumary Digits & radial head dislocationChondrosarcomatous Degenera-tion - occurs in 20%, esp hips

Tuberous Sclerosis - Cortical thickening, can sim pagets Flat osteomatous protuberances on cortexParaventricular tubers, Renal masses, Pulm infiltratesZits, Fits & Nitwits, lytic lesions poss but rare

Neurofibromatosis - Von Reck-linghausens (NF-1) assoc w boneFamily Hx #1 presentation, Fx w pseudoarthrosis alsoST dysplasia induced by abn nerves - Elephant ManABN TRABECULATION PAT-TERN, "Ribbon Ribs", mult NOFOssification centers & digits can have marked overgrowthUNILAT ANTERIOR bowing of distal leg (osteogenesis is bilat, fetal mal-position causes post bow)Extensive subperiosteal hem w exuberant callus poss

Bizarre facial dysplasia - Sphe-noid #1, orbit asymetryPost orbit does not develop, Poss II' to optic gliomasSharply angled Scoliosis - wors-ens even P growth stopsScalloped post vert bodies - mult spinal meningocelessmall vert body, long sclerotic post elements"Dumb-bell" tumors - widen for-mena & erode pediclesFocal Gigantism of a digit Cafe Au lait spots, gliomas, lesch nodules of irisRenal artery Stenosis & Neurofi-brosarcoma possBlount's Dz - Osteochondrosis Deformans Tibiaelat dilocation of tibia, wedge-shaped deformity of medial tibia Infantile Form - physiologic bow-ing fails to straighten w growthHisto shows disturbed medial epiphyseal endochondral ossJuvenile Form - less common,

segmental arrest of medial growth plateusually unilat, affects children 8-15yrs

Gaucher's Dz - Auto Rec, Dec lysosomal HydrolaseGlucosyl Ceramide accumulates in RES organs, 3 formsAdult - #1, mult spleen nodes, pulm & hepatic fail, deathJuvenile - 2-6yrs, mild w pre-dominate neurologic SxInfantile - hepatosplenomeg, se-vere neuro, early death90% have bone Sx - Avasc Nec, Osteomyelits, Myelofibrosis"Erlenmeyer Flask" - marked cor-tical thickenig at dist fem"Fish Mouth" vertebra, bone in-farcts, Periosteal Rxnmult sharply demarcated lytic le-sions poss

Mucopolysaccharidoses - lyso-somal storage disorder

Morquio's - the only one NOT assoc w mental retardationtype IV, skeletal changes pre-dominate, auto rec"Bullet" shaped vert w gibbus due to dysplasia of L1 or T12"Wineglass" pelvis & iliac wing flaring, dwarfismshortened & thickened metacar-pals & carpalsPremature degenerative arthritis, corneal opacities Hurler's - type I, gargoylism, auto rec, dwarfism, MR after 1-3yrsmain Sx are neuro, "bullet" ver-tebra are seen though lesscalverial thickening, J shaped sella, frontal bossingScaphocephaly due to closure of sag sutureClaw hands, thick flaring ribs

Hemolytic Anemias - Thalas-semia, sickle cell, Non-spherocytic Congenital, causes profound

marrow hyperplasiaWidened Spongiosa w coarse trabecular pattern, thin cortex

Hadju-Cheney - Primary Acroos-teolysis, tufts never develop, os-teoporosisWormian bones & Kyphoscolio-sisAcroosteolysis also occurs w scleroderma, frost-bite & burnPyknodysostosis, psorisis & Pachydermoperiostitis

Holt-Oram Syn - Cardiomelic syndrome, Auto dom, effects up-per ext onlyassoc w variety of clavicle, ster-num, radius anomaliesHands #1 - carpal coalition, ab-sent thumb etcHeart defects predominatly con-ductive, septal #1 structural de-fectsMarfan's Syndrome - auto dom defect in collagen cross linking

Generalized Osteopenia, Doli-chocepahly, prominent jawThumb & 1st toe dispropor-tionatly long, pes planusScoliosis in 60%, Scheuremann Dz, Dural ectasia w post scallop-ingligamentous laxity, premature os-teoarthritis, slipped cap fem epiphysisCardiovascular - cause of death in 90%, recurrent biliary obsOccular lens dilocation, cystic lung Dz, recurrent pneumothorax

Homocystinuria - familial defect in collagen synthesis, simulates Marfan'sarachnodactaly, scoliosis & post scalloping of vert bodies in bothOsteoporosis occurs w this but not Marfan'sligamentous laxity present but no joint contracture as in Marfan's

Macrodystrophia Lipomatosa -

macrodactyly due to neural fi-brolipomaincrease in size of all elements & structures of one or more digitsfibrofatty tissue infiltrates epi-neurium, growth stops at puberty

Polydactyly - Preaxial means lateral, index or thumb duplica-tionPostaxial - medial, more com-mon 5th digit duplicationSyndactyly - most commonly in-volves the 3rd & 4th digits

Infantile Coxa Vara - proximal focal femoral neck defeciency, unilatcauses varus deformity of femo-ral neck, widened growth platechild presents w lurching pain-less gait

Madelung Deformity - volar an-gulation of distal Radiusrelatively long ulna & radial-ulnar

space widenedforms a V shaped radial & ulnar articulartion w carpalscarpal angle decreased, volar subluxationII' to premature fusion of radial physis, assoc w traumaalso seen w Turner's & multiple enchondromatosis

Radial Ray Defects - rare, 40% assoc w VACTERL anomaliescan be absent thumb or entire radius

Klippel-Feil Syndrome - Fused cerv & upper thoracic vertebra

Sprengel's Deformity - scapula elevated & fused to cervical ver-tebra

Congenital Posterior Bowing of Tibia - foot dorsiflexedetiology unkown, progressive im-provement w growth

eventually becomes staight w minimal shortenening

Skeletal DysplasiasSKELETAL DYSPLASIASDisturbance of bone growthRhizomelic Dwarfism - proximal limbs, humerus & femur, achon-droplasiaMesomelic Darfism - shortened intermediate segAcromelic Darfism - distal short-ening, asphyxiating thoracic dys-plasiaMicromelic Dwarfism - shortened entire limb, jeune syn, thanato-phoric

Achondroplasia - Rhizomelic Shortening (prox long bones)Scalloped post vert bodies as seen in acromegalyForamen Magnum small - Hy-drocephalus causes lg headNarrow dist spinal canal - causes

prob w minimal herniationShort pedicles & narrow intrape-dicular distance MUST be pre-sentFlattened Acetabular Angle & Il-iac wings

Spondyloepiphyseal Dysplasia - Auto dom, dwarfism from spine & hipsDDx - Morquio's, several distin-guishing featurespresents at birth, morquio's seen at end of first yeardeficient ossification of pubic bones & narrow pelvic angle, not flaredvarus deformity of hips, Mor-quio's has valgusNO involvement of the hands Corneal detachment rather than corneal clouding

Multiple Epiphyseal Dysplasia - irreg mottled calc of epiphysislate onset of dwarfism, mild limb

shortening Premature DJD, short palanges, auto rec w NO shortened life-spanminimal spine effects DDx from Spondyloepiphyseal dysplasiasDDx - stippled epiphysis also seen w cretinism & warfarin em-bryopathy

Metaphyseal Chondrodyspla-sia - severe short limbed dwarfsall have Erlenmeyer flask de-formity extending to diaphysis

Schmid Type - most common, AutoDomwidened epiphysis, cupped metaphysis & coxa varamimics Vit D refractory Rickets

Metaphyseal Dysplasia - Pyle Dz, often tall & asymptomaticeffects long bones esp in hand & medial clavicle, genu valgumsplaying of ends w thinned cortex

Chondroectodermal Dysplasia - Ellis-van Creveld SynAccelerated Skeletal maturationPolydactyly & congenital heart Dz freq, Septal defects #1Nails, hair & teeth ALWAYS in-volvedCleidocranial Dysotosis - delayed ossification of midline structureslarge head w Wormian bones, hypoplastic sinuses, bossing, lg mandiblehypoplastic chest, medial & lat portions of clavicle don't fusedelayes ossification of symphysis pubisspina bifida occulta, varus hip, short radius

Cretinism - congenital Hypothry-roidism, Delayed skeletal matu-rationStippled Epiphysis, may remain open indefinetly, wide sutures & fontanelles

Demineralization but dense ver-tebral marginsCalvarial thickening, caxa vara, wedge vert bodies in adulthoodNO skeletal change w adult on-set

Angiovenous Dysplasia - AVM, hemangioma or venous malfor-mationmost asym, may cause over-growth of affected limb due to inc flowcan cause focal bone errosions, look for phleboliths

Hip Dysplasia - femoral head cartilage <50% covered by ace-tabulumusually displaced post & lat, will eventuall migrate superior1) seated at rest, lax w stress, 2)subluxated, 3)dislocatedMost important is to determine if it is reducible or notDynamic US Scanning - neutral

1st then stress during flexion & adductionTransverse view - head centered over & touching triradiate carti-lagefemoral metaphysis inferior & is-chium superior make cup for headCoronal view - gluteal muscles will be seen lat to iliac bone & headAbduction will demonstrate if hip is reducableMRI - may show iliopsoas tendon within joint if dislocatedInverted Limbus - labrum hyper-trophies & turns inward to jointprevents relocation, arthrography shows loss of "rose thorn" pg760 ACR37Femoral head ischemia - head rotates superior causing valgus deformityoccurs at younger age than Legg-Pertheslook for shallow acetabulum &

widened "teardrop" seen w chronic processWeberg Angle - adult head should be centered in acetabu-lumangle between vertical & line to upper margin of acetabulum both lines originate in center of femoral head, 20-46deg N, smaller bad

Proximal Focal Femoral Defi-ciency - dysgenesis of prox fe-murprobably II' to in utero vasc acci-dent, most unilat, isolated anom-aly70% have ipsilat fibular agenesis prob due to same vasc accidentpresent as unilat short limb, no painUS - shows a cartilage connec-tion between head & shaft in mild formsevere form has no connection or no femoral head

acetabulum shallow or absent due to dysplastic femoral headApert's Syndrome - Acrocephalo-syndactylyCraniosynostosis of coronal su-ture resulting in brachiocephalyalso hypoplastic ant fossa, prominent sella turcica & choroid calcificationmidface hypoplasia, hypertelo-rism, hydrocephalusSyndactyly - results in "mitten hand" & "sock foot"Symphalangism - progressive obliteration of interphalangeal jointsfusion of other joints as well in-cluding tarsals & carpals

Arthritis and Benign Joint Processes

BENIGN JOINT PROCESSESSynovial Osteochondromatosis - usually monoarticularMetaplasia of the synovium - car-

tilage deposits on synoviumCalcium deposits in cartilage, Knee, hips & elbows #1

Pigmented Villonodular Syno-vitishemosiderin deposited causing fibrosis & Synovial prolifMonarticular degeneration of knee #1, hip #2most commonly effects extraar-ticular tendon sheathsPeriarticular cystic degeneration in hands & feet freq85% have osseous lytic lesions & cortical errosionsLg subchondral cysts w NO joint space narrowing typicalNO CALC & NO Osteoperosis, articular cartilage preserved until lateResembles nonossified synovial osteochondromatosisDDx - Synovioma, sim distribu-tion & ST masserrosions more smooth & no pe-

riosteal rxn

Sudec's Atrophy - Reflex Sym-pathetic Dystrophy, shoulder-hand syn 1) onset of painful & stiff shoul-der or hand joints, lasts 6mo2) Shoulder improves but hand continues to burn, ST wasting3) last stage may be 3-6mo or chronic, contractures, skin atro-phyNucs - shows inc flow & uptake, plain film shows osteopenia P 6wksTrauma is often intial event, se-verity does not influence out-comeTx w corticosteroids & sympa-thetic block w meds or surgAggressive Osteoporosis is hall-markDDx - dissuse osteoporosis, no ST wasting or skin atrophy assoc

Septic Hip - B strep in neonate,

H. flu in infant, S. aureus in childpresent w fever and immobile joint, X-ray N initiallyEffusion displaces med aspect of head >1mm relative to oppositeAspirtation for Dx, Emergent ar-throtomy & open drainage for Txhigh risk of cartilage destruction, 15% assoc w head osteomyelitisX-ray - <35% sensitivity, 1mm is sig for poss infection, need of aspirationUS - 90% sensitive for effusion, best in sagittal planeechogenicity of the fluid does not relate to need for aspiration

Lyme Disease - JRA type pres-entation possible if no TxErythema Migrans rash at site of deer tick bite, Spirochet

Gorham's Vanishing Bone - massive osteolysis II' to hema-giomatosisbone resorbed & replaced by an-

giomatous tissue, crosses joints & diskeffects children & young adults, any bone involvedno pain or expansile mass assoc, no Tx effective.

Collagen Vascular Disease

NO joint destruction

Scleroderma - Tight overlying skin causes calcinosis cutisDist phalangeal resorb - pencil-ing & acroosteolysis ST calc but less than dermato-myositisNO osteoperosis

Dermatomyositis - nonsuppura-tive inflam myopathyOnset 4-11yrs, Edema of SubQ tissues first SxMuscle also presents w edema & loss of fat-musc planes

Eventual fibrosis, calc & contrac-tureST calc in linear confluent pat-ternseen in hands, axilla, inguinal & chest wallBone undergoes dissuse resorb-tionNO terminal tuft resorbtion, malig joint contracture assocFever, rash, lymphadenopathy, splenomegaly & death assocAtony & dilation of the esopha-gus

Systemic Lupus Erythemato-sus - Alignment changes, NO ERROSIONSBoutoneire Deformity - lax joint capsules esp at MCP jointsreducable ulnar deviation typicalNonerrosive peripheral polyar-thritis w sim distribution as RACalc of tendenous insertions poss

Mixed connective tis Dz - sclero, SLE, polymyositis & RAOsteoporosis & soft tissue wast-ingNo erosions

TraumaCERVICAL SPINEPrevertebral soft tissue - 3mm from C1-C4, smooth contourAnterior vertebral bodies - in-teruption indicates serious injSpinolaminal line - disruption could indicate cord injuryC1 ant arch should be no more than 2.5mm from dens (5mm kids)Nerve Root Avulsion - most common in dist cerv spine

Jefferson's fx - split C1, CT to demonstrate all fx pointsUnstable only if Trans lig dis-rupted, seen if >7mm spread rarely assoc w an odontoid fx

Rotary fixation of the atlantoaxial joint - follows mild traC1-C2 move en mass, lat spaces unequal even w/o rotation

Clay Shoveler's fx - avulsion of lower spinous processexcesive force to the su-peraspinous ligaments

Hangman's fx - bilat neural arch fx of C2, ant Sublux of C2 on C3hyperextention & extraction in-jury, unstable but cord decompprevertebral ST swelling but NO facet dilocationant inf corner fx of C2

Hyperextention Teardrop Fx - avulsion of ant inf corner by ant long lig, C2 #1Usually no displacement of vert body

Hyperflextion Teardrop Fx - ant inf corner crushed anteriorly,

body retropulsedone of the most severe & unsta-ble, cause ant cord syn - quad & loss of pain

Unilateral locked facet - apo-physeal ligaments ruptureflexion & rotation inf, facets overide, rarely bilat

Ant Subluxation - hyperextention, 20% have delayed instabilitykyphotic angulation w narrowed ant disk space, wide post

Instability - inability to withstand physiologic loadsIntervertebral space widened, horiz displacement >3.5mmangulation >11deg, disruption of facets, mult fx's

LUMBAR SPINESeat belt injury - ant compres-sion of L1 or L2

Smith's fx - fx of post body

Chance fx - results from flexion, 10% assoc w bowel damagefailure of the post & middle spinal columns ant failure also poss

Spondylolysis - fx of the pars in-terarticularis of laminafx in neck of scottie dog on obl viewoften occurs in toddler yrs, not always significant

Spondylolisthesis - bilat pars fx, sup sublux ant to inf

HANDBennett's fx - fx at base of 1st metacarpal into carpomet joithumb adductors cause sliding, must be surgically fixedpsuedo-bennett's fx - no in-volvement of the joint

Rolando's fx - com fx at base of 1st met w joint involed

Mallet Finger or Baseball Finger - avul at dorsal base of dist phalextensor digitorum insertion makes surg fix mandatoryflexs w/o opposition due to loss of extensor

Volar Plate Fx - fx at the base of the mid phalanx along the volar aspect

Gamekeeper's thumb - avul of ulnar side of 1st prox phalanx

WRIST80% of axial loading force on ra-diusany radial fx can result in positive ulnar variance

Lunate/Perilunate Dislocation - ligaments to capitate disruptDorsal perilunate dislocation -

capitelum & carpals dorsal3x more common than lunate disloc, 75% assoc w Fx

Lunate dislocation - lunate pushed volar to radiusmanipulation can change one to the otherpie shaped lunate seen on AP viewpermanent median nerve dam-age can result from lunateassoc w capitate, radial styloid, & triquetrum fxCan cause dorsal instability of the wrist

Ulnolunate Impaction Syn - pos ulnar variance flattens med lu-natetriangular fibrocartilage thinned & often torn by long ulnasubchondral degen cyst devel-ops in lunate due to impaction

Kienbock's Malacia - avasc nec

of lunateassoc w negative ulnar variance, short ulna

Hook of Hamate Fx - need carpal tunnel view, parralel to palmusually due to fall onto an out-streched handprof baseball, tennis, & golfers can lever of hookUlnar Nerve which lies adjacent & outside tunnel often damagedCT may be helpful

Fracture of Scaphoid - avasc nec of prox frag common

Dorsal Instability of Wrist - dis-ruption of dorsal radiocarpal ligaments60% due to scaphoid fx, 10% due to triquetral fx (dorsal chip seen)ligament inj such as rotary sublux of scaphoid or perilunate disloc also

AP film - often shows widening of scapholunate jointLat Film - key to diagnosis of dorsiflexion instabilityshows volar angulation of lunate & capitate displaced volar (post)lines drawn thru vert axis of lu-nate & scaphoid angle >80deg (N 30-60)Palmarflexion instability - Ant displaced capitate & palmar an-gulation of lunate

Rotary sublux of Scaphoid - rup-tured scapholunate lig, scaphoid rotates volarlat view shows horizontal orienta-tion of scaphoidgap between scaphoid and lu-nate on AP view - "Terry Thomas Sign"

Triquetral fx - avul chip seen on dorsum of wrist patognomonicoccurs at dorsum and may cause dorsal instability of the wrist

horizontal compresion assoc w perilunate diloc, capitate &/or scaphoid Fx

Carpal Tunnel - carries median & ulnar N, Radial & Ulnar artFlexor digitorum Profunda deep & superficialis overFlexor dig Longus goes over flexor retinaculum, inserts to palmar aponeurosisCarpal tunnel syndrome - most common in obese middle age women

Carpal-Ulnar Dislocation - ulna & triquetrum no longer aligned

deQuervain's Stenosing Teno-synovitis - affects the extensors over radial styloidabductor pollicus longus & bre-vis, MRI shows fat planes in-flammedpain occurs w thumb movement,

most in young female during lac-tation

FOREARMColle's fx - dorsal ang of dist radius/ulnar styloid fx

Smith's fx - volar ang of dist radius/ulna fx

Plastic bowing deformity - bend but no break must be surgicaly broken & reset or lose sup & pronation

Monteggia's Fx - ulna fx, (90% proximal) & prox radius dislocmust examine prox radius or aseptic nec may resultPositive Ulnar Variance - can re-sult from any radial fx

Galleazzi's Fx - radial fx w disloc of distal ulna

Essex-Lopressti Fx - radial head

fx w dislocation of dist radial ul-nar

Barton Fx - Fx of the dorsal ar-ticular margin of dist radius

ELBOWFat pad displaced from post fossa following fxchild usually supracondylar, adult usually radial headChildren can have effusion with-out Fx - Dr. Ozonoff

CRITOE 1,5,7,10,10,12 - order & age of epiphysis ossification el-bow Capitulum, Radius, Internal epi-condyle (med),TrochleaOlecranon & External epicondyle (lat)All but lat epi fuse by 16yrs, 18 - lat fusedCome Rub My Tree Of Love - Erin Masada's pneumonic

Ligamentous InjuriesUlnar Collateral Lig - most impor-tant, resists valgus stressAnt thick cordlike, middle apo-neurotic, post thin & tranfreq stressed in pitchersAnnular Ligament - stabalizes radial head in pronation & supDislocation - radius & ulna to-gether #1Nursemaids - reduced w supina-tion & ext rotationRadial head freq w ulnar FxCommon Flexor Tendon - from med epicondyle, can avulse Extensor Tendon - inflam causes Tennis Elbow, esp anconius muscle

Olecranon BursaSubcutaneous - freq assoc w housemaids elbow & traumaSubtendinous - assoc w pitcher injuries, chips in fossa

Pseudodefect of the Capitulum -

defect in postlat articulation on MRmistaken for osteochondral le-sion or fxTrue osteochonritis would be lo-cated more ant in cart

Essex-Lopresti Fx - Radial head Fx w dilocation of dist radial ulnar joint

Volkmann's Contracture - com-plication of a supracondylar fxvascular compromise from bra-chial art injury or swellingmuscle & nerve ischemia results in flexion contracture of hand & wrist

Biceps Tendon Rupture - most common tendinous injurypt unable to flex biceps, pain over radial tuberosity

Little Leaguer's Elbow - osteo-

chondral injury to capitellumdue to repeated valgus stress

SHOULDERNeer Classifications for Fx's - based on # & angulation of fragsOne Part - 80%, surgical neck fx w no displacementTwo Part - Fx of surgical neck w displacement>45deg angulation or >1cm apart, ORIF requiredThree Part - greater or lesser tuberosity avulsed & displacedFour Part - both greater & lesser tuberosity displaceddevascularization of humeral head

Ant dislocation - #1, ext rotation and abductionhead seen inf and medial to the glenoidHill-Sachs deformity - Fx of postlat head of hum, 50%caused by inf lip of glenoid, dis-

loc likely to recurBankart deformity - frag off inf glenoid, less commonAxillary Nerve Injury assoc

Post dislocation - more dif to Dx, use scapular Y or Axillary veiwAP view - may be N, lose overlap of glenoid & head, sm space seenlook for lesser tuberosity avul or Fx of post rim of glenoidReverse Hill-Sach's - trough Fx of ant-medial aspect of humeral head poss

Traumatic hemarthrosis - blood displaces head inf mediallyCT may be helpful in fully evalu-ating a joint fx

Rotator Cuff Tear - narrowed subacromial space when chronicContrast to subacromion & sub-deltoid bursa on arthrogram

PELVISAcetabulum - CT needed to show free frags and subtle fx

Sacrum - fx 50% of time w pelvis fx, dificult to seelook for interruption of the arcu-ate linesstress fx can appear sclerotic in osteopenic pt, CT

Malaigne Fx - SI diastasis assoc w pelvic ring Fx60% chance of significant injury elsewhere in the body

FEMURFemoral Head Dysplasia - abn fem head & acetabular relation-shipEtiology - Familial or anatomic variance, crowding or breech90% effect femalesLaxity of capsule allows head Sublux & compress posst labrumeventually may dislocate

causeing labrum to flip downII' acetabular dysplasia follows if not correctedPavlik Harness - holds in flexion & ext rotationUS - greater than 50% of fem head should be in acetab

Femoral neck stress fx - dif to detect esp in elderlytype 1 - sclerosis w/o fx line evi-dent, bedrest for txtype 2 - sclerosis w fx line evi-dent, int fixationtype 3 - displaced fx evident

Long Bone Stress Fx - may pre-sent as sclerosis, NO Bx repeat in 1-2 wks, CT & MRI helpful

Femoral Muscle Avulsions Sartoius - ant sup iliac spineRectus Femoris - ant in iliac spineHamstrings - ischial tuberosity

KNEECollateral Ligaments - Medial at-tached to the meniscus, tears more freqMedial Collateral Ligament - tear assoc w segond & ACL injuryLateral has 3 parts - fibular col-lateral, iliotibial collateral & arcu-ate

Meniscul Tears - horiz Tears de-generative, vert tears post trau-maticMedial meniscus more likely to tear than lat, posterior > anteriorassoc w med collateral, ACL & Segond injuryBucket Handle - inner portion of lat meniscus displaced intracon-dylar Discoid Meniscus - more likely to be lat, prone to tearmore common in children, ie lat tears #1 in child

Pitfalls of Meniscul Tears - liga-

ment insertionsHumphry's lig - passes just ant to PCL, inserts post lat meniscusWrisburg Lig - passes just post to PCL, inserts post lat meniscusoblique form post horn of lat me-niscus to med fem condyleTransverse Lig - connects the med & lat ant menisciPopliteus Tendon - inserts on lat fem condyle, passes postlat me-niscusAnt medial meniscus is 1/2 the size of the posterior medial

Synovial Cysts - extrusion of synovium w no communiction seenGanglion Cyst - assoc w tendon-ous synovial compartmentsfilled w gelatenous fluid, often appear intramuscularBakers Cyst - between semimem tendon & med gastroc headfree communication to joint space, seen on arthrography

occasionally causes entrapment of the peroneal nerverupture can cause pain & swel-ling similar to thrombophebitis

Meniscal Cyst - comm w joint via meniscus tear, usually lateralgelatinous fluid prevents visuali-zation w arthrography Inclusion Cyst - seen w an intact miniscus

Plica - adhesive band to dist fe-mur, seen best w effusionMedial Patellar Plica - most likely to cause SxSuperior plica - between supra-patellar tendon & femurlateral placa - between lat coll ligament & femur

Pes Anserinus - attachment of semitend, gracilic & saratoriusattaches to medial tibia, N bursa should not be seen

ACL Tears - external rotation & abductionSegond's Fx - longitudinal fx of post & lat tibiaoccurs just dist to tibial platue, always seen w ACL tearDeepening of the lateral femoral sulcus - 100% specificMedial Meniscus & Medial Col-lateral lig complete triadTibial Platue Fx - assoc fibular fx tends to be adjacent to tibial fxrarely cause damage to popliteal art, 5% get peroneal nerve palsyTypes - compression, split, com-bined or bicondylarknee instability develops in 30% within 2yrs, 50% get DJD in 15yrs20% assoc w meniscal tear, may interfer w reductionTx - if <4mm displaced use brief immobilization & range of motion earlypoor outcome assoc w >10deg of varus angulation

collateral lig tears must be re-paired to reduce laxity50% require open reduction & internal fixation

Patella Alta - pattella subluxed superior due to pattellar ligament disrup

Knee Prosthesis - anatomic alignment crucial to stabilityfemoral component 7deg valgus +/- 3deg, tibial 90deg to long axistibial component also tilts 10deg post to allow complete flexionNormal Long Term Appearance - two common changesLucency bone prosthesis inter-face <2mm, esp at ant tibial re-gionStress Shielding of Femur - due to nonuniform load transfer linear band of inc bone density extending from portion of pros-thesisFailure - follows nonanatomic

component placement or liga-ment laxityTibial loosens most often, tilts va-rus w subsidence of med plateauPatellar component is the most common site of arthroplasty complicationsubsidence occurs in 15% but it often stabalizes (ie infrequent "failure")Infection - most serious compli-cation, occurs in <2%73% appear normal on plain film, abscence of signs does not ex-clude infecPeriprosthetic Fracture - assoc w osteopenia and rheumatoid ar-thritisusually incomplete and appear as sclerotic lines of impactionParticle Disease - granulomatous response to debris from wear & tear

FOOT & ANKLECavus - elevation of the arch of

the footPlantus - flattening of the arch of the foot

Maisonneuve Fx - proximal fibula Fx which is often associated w ankle fracturesproximal films must always be obtained to rule this outDr. Abrahams asked me this question during oral boards

Inversion-Adduction Injury - Lat lig rupture or trans fx lat malleo-lusangular forces from talus can cause obl fx of medial malleolus

Eversion Injury - Deltoid lig rup-ture & med malleolus FxDist tibiofibular lig tear, fx of dist fib including spiral typedoes NOT cause trans fx of lat malleolus

Jones Fx - trans thru base of 5th

metatarsaloccurs II' to inversion-adduction also

Calcaneal Stress Fx - linear band of sclerosis in post calcaBoehler's angle - 30-40 deg N, lines drawn post & antnot the best predictor of out-come, does not indicate ORIFAlignment of the post articular surface predicts outcomeCoronal thin section CT best for assesmentEssex-Lopresti classification for Fx's - tounge type or joint de-pression typeresult from forces at the angle of Gissane75% have some intra-articular component, all assoc w lumbar fx

Talar Neck fx - forced dorsiflexion

Kohler's Malacia - avasc nec of tarsal navicular, poss N var

seen in kids, Tx w immobilization

Lisfanc's Fx - fx dislocation of the tarsometatarsalsMed border of 2nd metatarsal aligns med border of 2nd cuneBunkbed Fx - fx disloc of 1st metatarsal & medial(1st) cunei-form

Chopart Dislocation - talo-navicular & calcaneo-cuboid joints dilocatedmid tarsal dislocation

Clubfoot - Usully Equinovarus, Navicular rotated med to talar headlat veiw shows talus & calcaneus parralel

Flatfoot - hindfoot valgus, navicu-lar rotated lat to talar headTalus rotates downward in front w navicular near dorsum

Halx Valgus - great toe turned latSubtalr Dislocation - dist foot dis-locates from fall onto inverted foottalonavicular & talocalcaneal joints disrupted, medial #1calcaneocuboid joint & ankle in-tactpoor outcome if assoc w talar Fx

Tillo Fx - lat epiphysis of distal tibiaoccurs in adolescence when fuseing from med to lat

Tendon Tear on MRI - degenera-tion, partial tear & tendinitis ap-pear siminc signal in substance of tendon, tendon enlargement seen w all 3Peronius, Post Tibial & Flexor Digitorum - fluid seen in sheathPost Tibial - rupture in women w rhuematoid, painful flat foot as-socFlexor Hallucis Longus - sheath

communicates w joint, eff may migrateAnt Tibial Tendon - rupture rare, tenosynovitis in downhill hikersAchilles - has no sheath so can be abn w no evidence of fluid on MRI

Navicular Fx - avulsion of cortical margin #1 midtarsal Fx deltoid ligament attachment in mid upper margin not significantly displaced, not a significant portion of articular sur-face

Hallux Valgus Deformity - lat de-viation of entire 1st toesesamoids not centered over joint & medial 1st head promen-inceHallux Rigidus Deformity - DJD causeing loss of dorsiflexion

Hammertoe - fixed flexion con-tracture at prox interphalangeal

jointClaw toe is flexion of dist inter-phalangeal joint

PEDIATRIC TRAUMABirth Trauma - Clavicle fx #1, fe-mur & humerus possusually spiral fx of diaphysis II' to breechUndetected metaphyseal & epiphyseal fx freqGood prognosis, pseudoarthrosis very rare

Battered Child - Metaphyseal avul or "Corner Fx" pathogmay see squaring of metaphysis, "bucket handle"Perisoteal rxn exuberant, perios-teum easily pulled freeVisceral injury & subdural hem assoc

Bowing Fracture in Child - due to longitudinal compressive forceassoc w fx of parralel bone, oc-

curs in naturaly bowing boneforearm #1, leg #2, fix w manual manipulation

Salter-Harris Fracturesany fx involving the growth plate I-VIZone of degen & transformation weakest portion of platebest place - no germ cells, sup-ply from metaphysisEpiphyseal blood supply critical to germinal matrix growth20% of all childhood Fx, dist ra-dius accounts for 50%Dist femur & prox tibia 3%, but 50% of growth arrest

Type I - growth plate shear, best prognosisHip injury can mimic disloc, ar-thro will show cart headdist Humerus Fx can sim disloc, epiphysis shifts en blocRadius remains aligned to capi-telum oss center

True fx radius is not aligned w capitelumApophyseal injuries to elbow, sup acetabulum & ischial tub

Type II - Fx thru metaphysis into physisEasy to reduce except at knee, tends to hem

Type III - Fx thru epiphysis into physisOffset of articular surface com-plicates reductionTillo Fx - most common, lat epiphysis of distal tibiaoccurs in adolescence when fuseing from med to lat

Type IV - Fx thru all 3 structures, difficult to alignTriplane Fx - prox tibial epiphysis fx in sag planemaetaphysis Fx in Coronal Plane, epi in horiz planeBony bar - cross union between

met & epi, arrest & twist

Type V - easiest to miss, only germinal cells crushedType VI - periosteal only, not X-ray DxType VII - Osteochondritis desi-cans

Osteochondritis Dissecans - Type VII Salter-Harris Fxchip Fx in articular surface of epiphysis, growth plate NormalAdolescent males - 15-20yrs, never seen before 10yrs or after 50yrspresent w locking, recurrent swelling or aymOsteochondral Fx from "nut-cracker"Medial femoral condyle lat por-tion in 75%, seen on tunnel viewtalus & capitellum also, Lat femo-ral condyle very rarely affectedpredisposes to early osteoarthri-tis

DDx - N ossification variant, epiphyseal dysplasia

Chondromalacia Patella - pain, errosion of cartilage in adoles-centdue to mechanical stress, T1 MRI best for evaluationcalled osteoarthritis in an adult.

MRI of Bone Marrow LesionsMRI CHARACTERISTICS OF BONE MARROW LESIONSGradient Recalled Echo Im-ages - partial flip angle followed by 180effective trans relaxation (T2*) instead of T2Susceptibility differences cause irreversible dephaseing, shorten-ing T2*Trabecula in marrow form inho-mogeneous susceptibilitiesloss of marrow signal results, not seen in diaphyseal region

Hemorrhage - Susceptibility from Iron products also causes signal loss

STIR - Short Tau Inversion Re-covery, starts w an initial 180a 90 is given when fat protons at their "null point", approx 350mseca second 180 then rephases the protonsIncreased marrow to lesion con-spicuity results, esp in fatty mar-row

FSE - Fast Aquisition Spin Echo, produces images w long TR in short timek-space filling is altered by aquir-ing trains of 2-16 echoes after one 90 pulsethe TE becomes a midline value instead of a fixed valuemiddle lines of k-space are assoc w the greatest signal & highest contrast

Fatty marrow sustains a higher signal intensity than conventional Spin Echoincreased difficulty distinguishing fatty from red marrowimproved sensitivity using fat suppresion techniques

Fat Suppresion Techniques - use chemical shift between fat & water protonsthey resonate at slightly diff fre-quencies due to enviroment dif-ferencesFat is suppresed by using low intensity RF centered on fat resonancefat magnîn is rotated mult times in the direction of the applied RFThis nulls the Z component of fat magnetization & blocks fat signalroutine spin echo or FSE se-quence can then be performed on water

Marrow Distribution - Red is intermediate T1 intensity, fatty is brightInfant pattern - homogeneous in-termediate intensity in all long boneschildhood pattern - intermediate metaphyseal intensity up to 10yrsOssifying epiphyses always con-tain high intensity FATTY marrowAdolescent Pattern - patchy transformation of metaphyseal marrowAdult Pattern - fatty marrow in all portions of long boneRed Marrow can be N in prox fem & humeral metaphysisalso seen in flat bones & axial skeleton, clivus is fatty though

Medullary Bone Infarct - occurs II' to ischemiaAcute appear as intermediate T1 & high T2Chronic shows more defined

borders, fibrous interface

Sickle Cell - frequently have ex-tensive cellular replacement Infarcts are freq complication due to sicklesRadiation Therapy - diffuse fatty replacement in field of portfollows 2000-4000 rads, edema & destruction of sinusoids intitallyDDx - anaplastic anemia, fatty replacement also but more patchy

Lymphoma - focal regions of dec marrow signal due to cellu-larity

Leukemic Bone - can have dif-fuse inc cellularity in active stage