Tumor

Question 1

Considerations for pelvic resection vs hemipelvectomy

Answer 1

sciatic nerve
femoral NVB
hip joint

Question 2

Classification of primary bone tumors pelvis?

Answer 2

<div>Enneking and Dunham Classification<br></br></div>

1- iliac wing: allograft/fixation<div>2-periacetabulum</div><div> -resection arthroplasty</div><div> -allograft/prosthetic composite</div><div> -saddle prosthesis</div><div> -custom metallic device</div><div> -hemipelvectomy</div><div>3-pubic rami/ischium: no reconstruction needed</div><div>4-sacrum</div><div><br></br></div>

Question 3

Classification/Tx of Metastatic Acetabular Lesions?

Answer 3

1-dome: cement THA, triflange, cup cage<div>2-medial wall/QP: harrington rod/flange cup, cage-cup, triflange, allograft-prosthetic composite, metal-augments + multihole highly porous cup</div><div>3-either column: cement augmented THA, saddle cup</div><div>4-both columns: cement augmented THA, saddle cup</div>

Question 4

Components of Mirel Criteria?

Answer 4

Site: U/E, L/E, peritrochanteric<div>Appearance: blastic, mixed, lytic</div><div>Size: <1/3, 1-2/3, >2/3</div><div>Pain: mild, mod, functional</div><div><br></br></div><div>>8 = 33% risk of fracture = fix</div><div>8= 15% risk</div><div><8 = 5% risk</div>

Question 5

ECOG Classification?

Answer 5

Eastern Cooperative Oncology Group:<div>0 - active, no restriction</div><div>1 - restriction with strenuous activyt</div><div>2 - ambulatory, ADLs, but no work activity</div><div>3 - Confided to bed>50% of time, ADLs</div><div>4 - completely disabled</div><div>5 - dead</div>

Question 6

Considerations for pathologic fracture management (known metastatic disease)

Answer 6

pre-op embolization (thryoid, RCC)<div>stable fixation of entire bone</div><div>med: bisphosphonate - decreases bone pain and risk of path fracture</div><div>radiation post-op of entire construct</div>

Question 7

Most likely primary in setting of diffuse mets with negative CT CAP?

Answer 7

Lung CA

Question 8

Most likely primary in acral mets

Answer 8

lung CA<div>acral = distal to elbow/knee</div>

Question 9

SINS Score components?

Answer 9

Spine Instability Neoplastic Score<div>-Location: junctional>rigid</div><div>-alignment</div><div>-Pain</div><div>-Bone Lesion Quality</div><div>-Vertebral body involvement</div><div>-Posterior column involvement</div><div><br></br></div><div>0-6 = stable</div><div>7-12 = unsure</div><div>>12 = unstable</div>

Question 10

Staging for Ewing Sarcoma

Answer 10

Local: full length X-rays, MRI (soft tissue extent!)<div>Systemic: bone scan, bone marrow biopsy (r/o leukemia), CT chest, LDH, FISH (molecular studies)</div>

Question 11

Poor Prognostic Features for Ewings?

Answer 11

<div><b>Metastatic disease</b>: bone mets worse than lung mets</div>

Patient Factors: age>14, male<div>Tumor factors: size and volume (>8cm/200cm3), location (central>distal), molecular path (fusion product), chemo response (<90% necrosis)</div><div>Systemic factors: high LDH (>200), esr, crp, wbc</div>

Question 12

Prognosis for Ewings?

Answer 12

<div>Survival</div>

Mets = 25% at 10 years<div>No Mets = 60% at 10 years</div>

Question 13

“Indications for adjuvant radiotherapy in Ewing’s?”

Answer 13

<div>Failure to achieve local control/cure</div>

<div><div>-Non-resectable tumour</div><div>-Positive margins</div></div>

Diffuse metastatic disease<div>Poor Chemo response</div><div><br></br></div>

Question 14

Relative Indications for amputation in primary bone tumour

Answer 14

Pathologic fracture contaminating compartments<div>Extensive NVB involvement</div><div>Function of Amp> than that of salvage</div>

Question 15

Poor Px factors for Osteosarcoma

Answer 15

<b>Overall stage, Presence of Mets</b><div>Tumor factors: size, location, response to chemo, positive margins, secondary sarcoma, tumor grade (conventional vs surface)</div><div>Systemic markers: high ALP/LDH, P-glycoprotein</div>

Question 16

RT dose for MM?

Answer 16

40-50 Gy<div>(10-15 fractions of 3 Gy)</div>

Question 17

Association or Extra-osseous findings with Fibrous Dysplasia

Answer 17

<div>Metabolic Syndromes</div>

<div>-hyperT, hyperPLT, high GH (Acromegaly), high adrenals (Cushings), hypophosphatemia</div>

<div><br></br></div>

McCune Albright<div> -triad of Cafe au Lait spots (coast of Maine), endocrine issues (precocious puberty), unilateral polyostotic FD</div><div><br></br></div><div>Mazabraud Syndrome</div><div> - soft-tissue intramuscular myxomas</div><div><br></br></div><div>Cherubism</div><div>-FD involvement of mandible/maxilla</div>

Question 18

Graft to use for fibrous dysplasia

Answer 18

Allograft (cortical>cancellous)<div><br></br></div><div>lowest risk of graft being replaced by dysplastic bone</div>

Question 19

fibrous dysplasia can transform into which malignancies

Answer 19

osteosarcoma>FS, CS, MFH<div><br></br></div><div>(not Pleomorphic undiff sarcoma)</div>

Question 20

NF is associated with which tumours?

Answer 20

Astrocytoma - benign CNS tumour<div>MPNST</div><div>others: melanoma, leukemia, rhabdomyosarcoma, pheo, pancreatic endocrine</div>

Question 21

Good Px factors for UBC steroid injection?

Answer 21

Patient: age>8<div>Lesion: small, uniloculated, proximal humerus</div><div>Tx: multiple injections</div>

Question 22

Overall Px factors for UBC healing?

Answer 22

Patient: age>10 (90% chance) vs <10 (60%)<div>Lesion: >2cm from physis = lower recurrence</div>

Question 23

Complications of UBC?

Answer 23

LLD<div>Varus malunion</div><div>Physeal Arrest</div><div>AVN of femoral head</div>

Question 24

ABC Characteristics

Answer 24

Young<div>Assx with USP6 mutation</div><div>Can occur subperiosteally</div><div>MRI: fluid/fluid levels (DDx: telangiectatic OS, GCT, # through UBC)</div>

Question 25

RFs for developing metastatic dz in isolated STS?

Answer 25

Tumor type <b>(high grade)</b><div>Size >5cm</div><div>Depth (under deep fascia)/Compartment involvement</div>

Question 26

Components of AJCC for STS?

Answer 26

Grade<div>Tumor (size>5cm, depth=deep)</div><div>Nodes</div><div>Metastatic Disease</div>

Question 27

“STS that doesn’t require chemo?”

Answer 27

Angiosarcoma

Question 28

STS that metastasize to lymph?

Answer 28

CREAMS<div>Clear cell chondrosarcoma</div><div>Rhabdomyosarcoma</div><div>Epithelioid</div><div>Angiosarcoma - rmr chemo doesnt help</div><div>Myxoid liposarcoma</div><div>Synovial Cell Sarcoma</div>

Question 29

Tx of MFH of bone?

Answer 29

Surgical Excision and chemo<div>(rarely radiation)</div>

Question 30

Radiation Therapy: adv/disadv to pre vs postop?

Answer 30

PRE-OP<div>-Adv: LOWER dose (50Gy); a non-op tumour can become resectable; improve margin; decreases intra-op tumour seeding</div><div>-Disadv: delayed wound healing; histologic diagnosis may be difficult; margins may be difficult</div><div><br></br></div><div>POST-OP</div><div>-Adv: better surgical staging, total dose is based on residual tumour burden, better wound healing, easier surgical resection of tumour, if positive margins left–> easier to define them</div><div>-Disadv: Higher dose, possibility of seeding other tissue, healing issues may delay XRT, volume of irradiated tissue is higher</div>

Question 31

Complications of Radiation Therapy?

Answer 31

Acute<div>-Local: skin irritation/desquamation, infection, wound healing, local edema, physeal arrest</div><div>-Systemic: GI upset, anorexia, fatigue, urinary frequency</div><div><br></br></div><div>Chronic</div><div>-Local: Fracture, Secondary Sarcoma, Growth arrest, Fibrosis, Osteonecrosis, Chronic edema</div><div>-Systemic: chronic edema, chest wall abnormalities, scoliosis</div>

Question 32

RFs for # from radiation?

Answer 32

Patient factors: female, age>50<div>Tumour: anterior thigh</div><div>Treatment: <b>radiation dose >60Gy</b>, circumferential radiation, periosteal stripping, neoadjuvant chemo</div>

Question 33

Approach to fracture secondary to radiation

Answer 33

1-R/O infection and tumour recurrence<div>2- HIGH non-union rate (load sharing and tumour prostheses are good options)</div><div>3 - PROLONGED union (up to 18 months)</div><div>4 - complication rates >50%</div>

Question 34

Soft Tissue Coverage for Tibia?

Answer 34

-Prox: Gastrocs<div>-Mid: Gastrocs, soleus, propeller</div><div>-Distal: Propeller, reverse sural, FHL flap, free flap</div>

Question 35

Primary malignancies that respond solely to surgical management?

Answer 35

Chondrosarcoma<div>Chordoma</div><div>Low grade OS (parosteal)</div><div>Adamantioma</div><div><br></br></div>

Question 36

Posterior Spinal Tumors?

Answer 36

“OO<div>OB</div><div>OC</div><div>ABC</div><div>‘oh oh oh ahhh’</div><div><br></br></div><div>note: only malignant posterior spien tumour is metastatic disease</div>”

Question 37

DDx for epiphyseal lesions?

Answer 37

Benign: GCT, Chondroblastoma<div>Malignant: Clear cell chondrosarcoma</div><div>Non-Tumour: infection</div>

Question 38

Calcifications of STS?

Answer 38

SEE A Fat HPV Muscle<div>Synovial Sarcoma</div><div>Extraskeletal OS</div><div>Extraskeletal CS</div><div>Angiosarcoma</div><div>Fat: lipomatous tumour, atypical lipoma</div><div>Hemangioma, HO</div><div>Phlebolith</div><div>Vasc malformation</div><div>Muscle: MO</div>

Question 39

MR features of soft tissue tumour that make it a Determinate Lesion (no biopsy) vs a Interdeterminate lesion (BIOPSY!)

Answer 39

<div><u>Determinate Lesion</u></div>

Homogenous signal<div>Isointense to Fat on all MR sequences</div><div>Occasional fibrous septae</div><div>No post-contrast GAD enhancement</div><div><br></br></div><div><u>Indeterminate Lesion</u></div><div>Heterogenous signal intensity</div><div>Lack isotense signal compared to fat</div><div>Post-contrast GAD enhancement</div><div>NECROTIC areads</div><div>DDx: lipoma variant, ALT, Sarcoma</div>

Question 40

Differences between ALT and WDL?

Answer 40

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Question 41

Approach to the management of Liposarcoma?

Answer 41

1-Referal to Sarcoma Centre<div>2- Multidisciplinary approach</div><div>3- Wide en bloc margin free excision</div><div>4- radiation (pre or post)</div><div>5 +/- chemo (myxoid)</div>

Question 42

Core/FNA vs Incisional Biopsy?

Answer 42

Core/FNA<div>-Adv: good for soft tissue, no OR, less risk of contamination/hematoma/path #</div><div>-Disadv: sampling error, not enough tissue, 85% accuracy</div><div><br></br></div><div>Open Bx</div><div>-Adv: diagnositc accuracy 96%</div><div>-Disadv: risk of inx, bleeding/hematoma, path #</div>

Question 43

Biopsy Principles

Answer 43

-Perform after clinical, lab and radiographic test complete<div>-Perform with definitive treating surgeon, notify pathologist before bx</div><div>-Tourniquet: inflate but do not compress</div><div>-Incision: small, in-line with future incisions for limb salvage surgery</div><div>-Bx tract is considered contaminated</div><div>-Approach: minimal contamination, single compartment, avoid NV structures, minimal retraction, meticulous hemostasis</div><div>-Bx: leading edge of tumour, cortical window=circular/oval, plug with PMMA</div><div>-Frozen section sent intra-op with surgeon to patholgist to ensure adequate tissue obtained</div><div>-no drains for closure</div>

Question 44

Low vs High Grade Lesions?

Answer 44

Low: well diff, few mitosis, moderate atypia, low risk mets <25%<div>High: poorly diff, high mitotic rate, high cell:matrix ration</div>

Question 45

HyperCa Mx of malignancy?

Answer 45

IVF: NS 250cc/hr for U/O>100cc/hr<div>Calcitonin: immediate Ca decrease</div><div>Zoledronic acid (4mg IV over 15 min): kicks in day 2-4</div><div> -Can use denosumab if zoledronic acid not working</div>

Question 46

Small round cell tumor differential (by age)?

Answer 46

”< 5 yrs: neuroblastoma or leukemia<div>5-10 yrs: eosinophilic granuloma</div><div>5-30 yrs:Ewing’s sarcoma</div><div>>30 yrs: lymphoma</div><div>> 50 yrs: myeloma<br></br></div>”

Question 47

Tx, Px of common malignant tumours?

Answer 47

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Question 48

Adjuncts to surgery for metastatic bone disease?

Answer 48

-bisphosphonates: decrease bone pain/fracture rate<div>-radiation</div>

Question 49

Adjuncts during extended intra-lesional curretage

Answer 49

-high speed burr<div>-cryotherapy<br></br><div>-cement/PMMA</div><div>-phenol</div><div>-peroxide</div></div><div>-hypotonic saline</div><div>-argon laser</div>

Question 50

GCT Treatment?

Answer 50

Systemic: Bisphosphonates, Denosumab<div>Surgical:</div><div>-extended intralesional curretage with adjuncts and reconstruction</div>

Question 51

<div>Which of the following is NOT true of ABC</div>

<div>a.Fluid fluid levels are pathognomonic with ABC on MRI</div>

<div>b.ABC can occur subperiostially</div>

<div>c.ABC is generally associated with USP6 mutation ??</div>

<div>d. Occur in people under 20</div>

Answer 51

Answer: A (GCT and CB can have fluid fluid levels)

Question 52

Methods to control bleeding intra-op with tumour resection?

Answer 52

<ul> <li>Flo-seal (spray tisseel)</li> <li>Bone cement</li> <li>Epinephrine soaked gauze</li> <li>Bone wax</li> <li>Get the tumor out</li> <li>If all else fails, embolize emergently in angio suite</li></ul>

Question 53

<div>Management of hypercalcemia of malignancy?</div>

Answer 53

“<ul> <li>Intravascular expansion with NS at 200-300cc/hr for urine output of 100cc/hr</li> <li>Calcitonin for immediate serum Ca++</li> <li>Zoledronic acid (4mg IV over 15mins)</li> <ul> <li>Kicks in around day 2-4 for maintenance of lowered calcium</li> </ul> <li>Denosumab is an option if refractory to zoledronic acid</li> <li>Loop diuretics are no longer considered part of the algorithm<br></br> </li> <li>ECG changes:</li> <ul> <li>Earliest change is shortening of the QT interval</li> <li>If severe, can see ““Osborne J waves,”” arrhythmias including ventricular irritability and VF arrest</li> </ul></ul>”

Question 54

pre-op vs post-op RT?

Answer 54

“<div> <div> <div><img></img></div> </div></div>”

Question 55

Presentation and histology of MO? Not a RC Q.

Answer 55

<ul> <li>Similar to heterotopic ossification</li> <li>Self-limiting reparative process in response to trauma</li> <ul> <li>75% have history of trauma</li> </ul> <li>Proliferation of fibroblasts centrally, bone forming osteoblastic elements peripherally</li> <ul> <li>Progresses centrally over the course of weeks</li> <li>Can have periosteal reaction with adjacent bone</li> </ul> <li>Painful firm mass 2-6 weeks post-injury</li> <li>Thigh, shoulder, buttock, elbow</li> <li>Biopsy:</li> <ul> <li>Osteogenic sarcoma has immature bone peripherally</li> <ul> <li>Growing OUT</li> </ul> <li>MO has mature bone peripherally with fibroblasts +/- mature bone centrally</li> <ul> <li>Grows from edge IN</li> </ul> </ul> <li>Treatment:</li> <ul> <li>Generally pain improves</li> <li>High recurrence is excision too early (delay until matured 6-12months)</li> <li>Consider low dose rads or indomethacin to limit recurrence</li> </ul></ul>

Question 56

Management Considerations for MM?

Answer 56

<ul> <li>Treatable, but not curable</li> <li>Remission can be achieved with chemo, steroids, targeted therapy, stem cell transplant</li> <li>Bone lesions: radiation (can be curative in solitary plasmocytoma), bisphosphonates</li><li>hyperCa tx (CRAB)</li></ul>

Question 57

Relative indications for amputation in sarcoma?

Answer 57

<ul> <li>Pathologic fracture with contamination of compartments</li> <li>Unable to remove tumor safely with NV bundle involvement</li> <li>Function of amputation > than that of salvage</li></ul>

Question 58

ddx benign aggressive lesions?

Answer 58

<div><ul><li>ABC</li> <li>GCT</li> <li>CMF</li> <li>Osteoblastoma</li> <li>Chondroblastoma</li></ul></div>

Question 59

JAASOS 2018 - STS indications for CT C/A/P?

Answer 59

<div>Staging typically only invovles CT Chest for STS, except for LAME</div>

<div>leiomyosarcoma</div>

<div>angiosarcoma</div>

<div>myxoid liposarcoma</div>

<div>epithelioid</div>

Question 60

JAAOS 2018 - megaprostheses

Answer 60

<div> <div> <div> <ul> <li>Summary</li> <ul> <li>Overall considerations</li> <ul> <li>prevent infx, improve ST attachment& bone/prosthesis interface</li> </ul> <li>Pelvis</li> <ul> <li>Resection + reconstruction</li> <ul> <li>CT custom implants, saddle implant becoming historic</li> <li>High risk of infx (40%), hematoma, dislocation</li> </ul> <li>Resection alone (leaving flail limb)</li> <ul> <li>Decreases risks of reconstruction</li> <li>Because implants getting better, may be historic</li> </ul> </ul> <li>Prox femur</li> <ul> <li>Difficulties with soft tissue attachments</li> <li>APC - allograft prosthetic composites designed to leave natural soft tissue attachments intact</li> <ul> <li>Complications: cost, infx rate, nonunion, graft absorption</li> </ul> <li>Unipolar/bipolar heads in young patients to preserve acetabular bone stock</li> <ul> <li>Can use in elderly patients who will die soon</li> </ul> </ul> <li>Distal femur</li> <ul> <li>Considerations: ligamentous laxity - need stability and ROM</li> <li>Improvements in design include: deepening and lateralizing the troch- lear grove, making the distal femur component smaller, using thicker stems, developing new coating surfaces for press-fit implants to avoid the use of cement, introducing more wear- resistant polyethylene, and using a modular implant system for ease of use </li> <li>Peds</li> <ul> <li>If close to skeletal maturity - do contralateral epiphysiodesis</li> </ul> </ul> <li>Total femur</li> <ul> <li>Risk of infection with: big resection, large metal surfaces, increased or time, comorbidities, repeat hospitalization</li> </ul> <li>Proximal tibia</li> <ul> <li>Most common site of failure</li> <li>Challenge: patellar tendon</li> <li>Study: Best function is with direct attach of Extensor Mechanism to prosthesis with an artificial tendon & medial gastroc flap</li> <li>Study: APC vs MP - 10y survival APC 93% vs 78.8% for MP</li> </ul> </ul> </ul> </div> </div></div>

Question 61

<div>Lesions that can be treated with bisphosphonates</div>

Answer 61

“<ul> <li>Mets</li> <li>Multiple myeloma</li> <li>Fibrous dysplasia</li> <li>Paget’s disease</li></ul>”

Question 62

Which physes are intra-capsular?

Answer 62

<div>Proximal humerus</div>

<div>Distal humerus</div>

<div>Proximal femur</div>

<div>Distal fibula</div>

Question 63

Absolute and Relative C/I to Van Nes Rotationplasty

Answer 63

1. Sciatic nerve dysfunction<div>2. Venous and arterial pathology</div><div>3. Impaired ankle extension</div><div>4. Expected psychosocial problems</div>

Question 64

Patients who undergo transtibial amputation must exert which percentage of increased energy for ambulation as compared to baseline?<div>A. 80%</div><div>B. 65%</div><div>C. 40%</div><div>D. 25%</div>

Answer 64

D. 25%<div>Patients who undergo transfemoral amputation exert 65% more energy for ambulation compared to baseline. Patients with transtibial amputations exert 25% more energy compared to baseline.<br></br></div>

Question 65

“A 20-year-old right-hand dominant man reports worsening left shoulder stiffness. He has a history of unremitting joint ankylosis that began in childhood (Figure 1) and worsened following two earlier procedures. On physical examination, his left shoulder is stiff and he has symmetric hallux foot deformities. Figure 2 is his current radiograph. In what gene is the associated mutation found?<div><br></br></div><div><img></img><img></img><br></br></div><div><br></br></div><div>A. cAMP</div><div>B. ACVR1</div><div>C. GNAS</div><div>D. LRP5</div>”

Answer 65

B. ACVR1<div><br></br></div><div>Fibrodysplasia ossificans progressive (FOP) is a disorder in which the skeletal and connective tissue are progressively replaced by bone. A minor trauma or injury can result in extensive heterotopic bone. The disorder is inherited in an <b>autosomal dominant</b> fashion. <b>The mutation affects the ACVR1 gene, which is a type I bone morphogenetic protein (BMP) receptor that becomes constitutively active once mutated</b>. The type I BMP receptor then performs signal transduction through either the Smad pathway or the mitogen-activated protein kinase (MAPK) pathway to affect transcription at the target gene level. <br></br><br></br>Regarding the cAMP gene, fibrous dysplasia arises from a somatic activating mutation in the GNAS gene that results in a constitutively active adenylyl cyclase and dysregulated cAMP production, expression, and activity. <br></br><br></br>The low-density lipoprotein receptor-related protein 5 (LRP5) gene plays a role in the bone development. Primary osteoporosis results from a missense mutation in LRP5. The mutation reduces signaling activity through the Wnt pathway and results in decreased bone formation.<br></br></div>

Question 66

“Figures 1 through 3 show the radiographs and photomicrograph obtained from a12-year-old boy who is right-hand dominant. He reports having spontaneous right forearm swelling and pain for the previous 2 months.What is the best next step?<div><br></br></div><div>A. Radiotherapy</div><div>B. Wide resection</div><div>C. Local resection</div><div>D. Medical management</div><div><br></br></div><div><img></img><img></img><br></br></div>”

Answer 66

D. Medical management<div>Chronic recurrent multifocal osteomyelitis is an inflammatory bone process usually seen in children. It is frequently characterized by focal pain and swelling and produces nonspecific radiographs that could be interpreted as indicating malignancy. The biopsy however is negative for small round blue cells or other changes suggestive of malignancy. The condition is a noninfectious osteomyelitis and is therefore not treated with antibiotics. Chondrosarcoma is extremely rare in this age group.<br></br></div>

Question 67

“Figures 1 through 4 show the radiographs and MRI scans obtained from a 40-year-old man who has a painful left medial knee mass. What is the most likely diagnosis?<div><br></br></div><div><img></img><img></img><img></img><img></img><br></br></div><div><br></br></div><div>A. STS</div><div>B. Chronic MCL tear</div><div>C. Parameniscal cyst</div><div>D. Hemangioma</div>”

Answer 67

These findings are most consistent with a vascular malformation along the medial aspect of the knee. Plain radiographs demonstrate phleboliths, and the MRI shows serpiginous vascularity with interspersed fat.

Question 68

“Figures 1 through 4 show the MRI scans and an immunohistochemical panel summary from a 27-year-old man who reports having left shoulder pain and weakness for the last 6 years. His history includes an ipsilateral distal ring finger amputation for a nonhealing ulcer. What is the most likely diagnosis?<div><br></br></div><div><img></img><img></img><img></img><img></img><br></br></div><div><br></br></div>”

Answer 68

Epithelioid sarcoma tends to occur in young adults in the second to fourth decades of life. It commonly occurs on the volar surfaces of the fingers, hands, wrists, and forearm. It stains positive for epithelial membrane antigen among other epithelial stains. It is often misdiagnosed as a nonhealing wound or ulcer owing to its seemingly indolent progression.

Question 69

“Figures 1 through 4 show the radiographs and MRI scans from a 70-year-old woman who is being evaluated for anterior knee pain. She has a known history of knee osteoarthritis. What is the most appropriate next step?<div><br></br></div><div><img></img><br></br></div><div><img></img><br></br></div><div><img></img><br></br></div><div><img></img><br></br></div>”

Answer 69

These images are most consistent with bone infarcts, which occur secondary to interrupted blood supply to the bone. Associated conditions include trauma, steroid use, hemoglobinopathies, alcohol abuse, and Caisson disease. They usually occur within the medulla of the metaphysis. Lesions have geographic margins on plain radiographs, low signal on T1-weighted sequences, and a double-line sign on T2-weighted sequences. Nonsurgical management and further observation is warranted.

Question 70

“Figure 1 shows the MRI scan from a 52-year-oldman with 6 weeks of left hip pain. He denies any recent trauma to the hip or recent infection. What is the best next step?<div><br></br></div><div><img></img><br></br></div><div><br></br></div><div>A. Protected WB</div><div>B. Core decompression</div><div>C. THA</div><div>D. Resection arthroplasty</div>”

Answer 70

Figure 1 demonstrates <b>transient osteoporosis of the hip</b>. This condition is seen as a homogenous pattern of edema involving the femoral head and neck. T1-weighted images demonstrate a low-intensity signal, whereas T2-weighted imaging demonstrates a high-intensity signal. <b>This condition is managed with protected weight bearing and is a self-limiting process that will improve without surgical intervention. </b>Transient osteoporosis of the hip presents in middle-aged men and in women during pregnancy.

Question 71

A 75-year-old man visits the office4 weeks after total knee arthroplasty. He has anteromedial skin necrosis. Staged revision arthroplasty is planned with flap coverage. What artery is the predominant blood supply of the most commonly used flap for this area of skin compromise?<div>A. Medial geniculate</div><div>B. Lateral geniculate</div><div>C. Lateral sural</div><div>D. Medial sural</div>

Answer 71

“<div>D. Medial sural</div><img></img><div>Wound complications following knee arthroplasty are uncommon but present a challenging problem. For anteromedial wound defects, the pedicled medial gastrocnemius is the most commonly used flap, given that the medial gastrocnemius muscle is larger and has more rotational excursion than the lateral gastrocnemius. Its predominant blood supply is the medial sural artery.<br></br></div>”

Question 72

PVNS - driven by overexpression of?<div>A. Ubiquitin-specific protease-6 (USP-6)</div><div>B. Colony-stimulating factor 1 (CSF-1)</div><div>C. Mouse double minute-2 homolog (MDM2)</div><div>D. Platelet-derived growth factor beta (PDGFB)</div>

Answer 72

The patient presents with a history and clinical findings typical of diffuse pigmented villonodular synovitis (PVNS). This disorder is primarily managed with surgical synovectomy and often requiresboth an anterior and a posterior approach. Local recurrence is common, and long-term sequelae include degenerative changes and eventualjoint destruction. Colony-stimulating factor 1 overexpression has been linked to the growth and development of PVNS. Early clinical trials using colony-stimulating factor 1 receptor inhibitors were encouraging, and continued drug development is ongoing. Ubiquitin-specific protease 6fusion genes have been linked to aneurysmal bone cysts and more recently to nodular fasciitis. Mouse double minute-2 homolog has been associated with the development of low-grade and parosteal osteosarcoma as well as atypical lipomatous tumors. The increased expression of platelet-derived growth factor beta has been associated with the development of dermatofibrosarcoma protuberans.

Question 73

A 28-year-old woman underwent curettage and packing of a benign but aggressive distal radial bone tumor 9 months ago. She returns with clinical and radiographic evidence of recurrence. The morbidity of surgery has been deemed extensive, and she has been offered medical management at this point. What is a recognized risk of medical management?<div>A. Hypercalcemia</div><div>B. Elevated levels of Vitamin D</div><div>C. Atypical vertebral fractures</div><div>D. Avascular necrosis of the jaw</div>

Answer 73

<div>D. Jaw AVN</div>

Denosumab is a monoclonal antibody that inhibits receptor activator of nuclear factor-kappa Β ligand (RANKL). It is designed to prevent bone loss and has been developed as an antiresorptive agent for the treatment of osteoporosis. More recently, it has been FDA approved for the treatment of recurrent and/or unresectable giant cell tumor of bone in cases in which surgery would demand unacceptably excessive morbidity. It has also been used as a means of downstaging the tumor, thereby allowing for more conservative surgery. Hypocalcemia is a recognized risk, and close monitoring and correction are recommended. <b>Avascular necrosis (AVN) of the jaw is a rare but significant recognized complication.</b> Concomitant dentoalveolar surgery increases the risk of AVN, and major dental procedures should be accomplished prior to the initiation of treatment to minimize risk. Supplementation with vitamin D is often necessary, in conjunction with calcium. Atypical vertebral fractures are generally encountered in osteoporotic patients who have abruptly discontinued therapy.

Question 74

“Figures show the radiographs, MRI, and histology from a 12-year-old boy who reports progressively worsening left knee pain that began approximately 5 months earlier. He denies significant trauma and reports no prior knee-related issues. He ambulates with an antalgic gait and is unable to squat or jump secondary to pain. His examination is notable for a large effusion, limited range of motion, and tenderness to palpation along the lateral femoral condyle. The most appropriate next step is<div><img></img><br></br></div><div><img></img><img></img><img></img></div><div><br></br></div><div>A. Curettage and packing.</div><div>B. Radiofrequency ablation.</div><div>C. Wide excision and reconstruction.</div><div>D. Observation and reassurance.</div>”

Answer 74

A. Curettage and packing<div>Chondroblastoma is a benign cartilagetumor that generally develops in the second decade of life and typically occurs within the epiphyseal region of long bones. Patients often present with pain; however, adjacent joint effusion, limited range of motion, and stiffness are alsocommon. Microscopic features include chondroid lobules, sheets of chondroblasts, anda distinct pattern of interspersed calcification <b>(chicken-wire calcification)</b>. <b>Secondary aneurysmal bone cysts are common, as are giant cells</b>. The treatment entails extended curettage and grafting. Radiofrequency ablation has been employed in smaller lesions, but it is not recommended for larger subchondral lesions that pose a higher fracturerisk. Wide excision and reconstruction would oncologically control the disease but is overly aggressive and excessivelymorbid. Observation and reassurance are not indicated, giventhat chondroblastomasdo not spontaneously resolve and are expected to progress, causing progressive bone and joint destruction and increasing pain and disability.<br></br></div>

Question 75

Complications of radiotherapy (ortho) (at least 5)

Answer 75

1. LLD<div>2. Joint contracture</div><div>3. Muscle atrophy</div><div>4. Pathologic fracture</div><div>5. Secondary sarcoma</div>