ORTHOPEDICS HYPERGUIDE MCQ 751-800

 

751. (1926) Q2-2336:

Osteoclasts have receptors for which of the following:

1) 1,25 dihydroxyvitamin D3

3) Osteoprotegerin

2) Parathyroid hormone

5) Calcitonin

4) Receptor activator of nuclear factor âkB

Osteoclasts have receptors for calcitonin. Calcitonin causes osteoclasts to shrink in size and reduces their ability to resorb bone

■Correct Answer: Calcitonin

752. (1927) Q2-2337:

After oophorectomy or menopause, bone loss per year is estimated to be:

1) 0.3% to 0.5%

3) 5% to 10%

2) 2% to 3%

5) 15% to 20%

4) 10% to 15%

The normal estimated age-related bone loss per year is 0.5%. After oophorectomy or during the first 6 to 8 years after menopause, bone loss can be as high as 2.0% to 3.0% per year

■Correct Answer: 2% to 3%

753. (1928) Q2-2338:

Estrogen deficiency results in which of the following:

1) Increased interleukin-6 (IL-6) expression

3) Decreased IL-6 expression

2) Increased osteoprotegerin (OPG) expression

5) Decreased macrophage colony-stimulating factor (M-CSF) expression

4) Decreased receptor activator of nuclear factor âkB ligand (RANKL)

Estrogen deficiency results in increased bone resorption. An increase in IL-6 expression stimulates osteoclasts to resorb bone.

An increase in M-CSF and RANKL results in increased osteoclastiCactivity. OPG decreases osteoclastiCactivity as a decoy inhibitor of RANK

■Correct Answer: Increased interleukin-6 (IL-6) expression

754. (1929) Q2-2339:

Androgens prevent bone resorption. Receptors for androgens are found on which of the following cells:

1) Osteoclasts

3) Osteoblasts

2) Osteoclast precursor cells

5) Mast cells

4) Osteocytes

Osteoblasts have receptors for androgens. Although androgens prevent bone resorption and may increase bone mass, the process is not understood at this time

■Correct Answer: Osteoblasts

755. (1930) Q2-2340:

Corticosteroids decrease bone mass through which of the following mechanisms:

1) Inhibiting calcium absorption in the intestines

3) Increasing calcium binding proteins

2) Decreasing calcium excretion in the kidneys

5) Increasing bone resorption at high doses

4) Increasing overall protein synthesis

Corticosteroids decrease overall protein synthesis. In the intestines, corticosteroids decrease calcium-binding proteins, hence decreasing the absorption of calcium.

Corticosteroids:

Decrease overall protein synthesis

Increase calcium excretion in the kidney

Inhibit bone formation and absorption at high doses

With the above changes, a state of secondary hyperparathyroidism exists. Correct Answer: Inhibiting calcium absorption in the intestines

756. (1931) Q2-2341:

Which of the following defines osteoporosis according to the World Health Organization:

1) 0.5 to 1.0 standard deviation (SD) below age-matched controls

3) 1.0 to 2.5 SD below age-matched controls

2) 1.0 to 2.0 SD below age-matched controls

5) 2.5 to 5.0 SD below age-matched controls

4) More than 2.5 SD below age-matched controls

Osteoporosis is a condition in which there is a deficiency of bone mass and microarchitectural deterioration of bone tissue. Osteoporosis is defined as a bone mass that is more than 2.5 SD below the mean for age-matched controls. Patients are considered osteopeniCwith mild to moderate bone deficiency with a bone density of 1.0 to 2.5 SD

■Correct Answer: More than 2.5

SD below age-matched controls

757. (1932) Q2-2342:

Which of the following features is associated with type 1 osteoporosis:

1) Primarily occurs in patients older than 75 years of age

3) Cortical and trabecular bone are affected

2) Female to male ratio is 2:1

5) Related to estrogen deficiency rather than calcium intake

4) Low turnover osteoporosis

Type 1 osteoporosis is the most common form of osteoporosis and is found in women during postmenopausal years. Type 1 osteoporosis is related to estrogen deficiency rather than a problem in calcium intake or absorption.

Features of type 1 osteoporosis include: Female to male ratio is 6:1

High turnover osteoporosis

Bone loss rate of 2% to 3% per year for 6 to 10 years following menopause

Trabecular bone is most affected

Related to estrogen deficiency rather than calcium intake

Correct Answer: Related to estrogen deficiency rather than calcium intake

758. (1933) Q2-2343:

Which of the following features is associated with type 2 osteoporosis:

1) High turnover osteoporosis

3) Loss of cortical and trabecular bone

2) Female to male ratio is 6:1

5) Greatest bone loss in the first 6 to 10 years following menopause

4) Related to estrogen deficiency

Type 1 osteoporosis is the most common form of osteoporosis and is found in women during postmenopausal years. Type 1 osteoporosis is related to estrogen deficiency rather than a problem in calcium intake or absorption.

Features of type 1 osteoporosis include:

Female to male ratio is 6:1

High turnover osteoporosis

Bone loss rate of 2% to 3% per year for 6 to 10 years following menopause

Trabecular bone is most affected

Related to estrogen deficiency rather than calcium intake

Type 2 osteoporosis, also called senile or involutional osteoporosis, is a low turnover osteoporosis and principally occurs in patients older than 75 years of age.

Features of type 2 osteoporosis include: Female to male ratio is 2:1

Patients older than 75 years of age

Low turnover osteoporosis

Trabecular and cortical bone affected

Associated with hip fractures

Related to a lifelong deficiency of calcium

Correct Answer: Loss of cortical and trabecular bone

759. (1934) Q2-2344:

Which of the following statements is false regarding the use of estrogen therapy to prevent osteoporosis:

1) Osteoblasts have estrogen receptors.

3) Estrogen decreases osteoclast activity.

2) Estrogen modulates calcium absorption and renal excretion.

5) The protective effect of estrogren therapy continues to prevent bone loss after therapy is discontinued.

4) Estrogen prevents osteoporosis in 80% of postmenopausal women.

Estrogen therapy is one of the main therapeutiCinterventions used to prevent osteoporosis in postmenopausal women. Features of estrogen interactions include:

Osteoblasts have estrogen receptors.

Estrogen indirectly affects calcium metabolism by modulating calcium absorption and renal excretion. Estrogen decreases osteoclast activity.

Estrogen prevents osteoporosis in 80% of postmenopausal women.

The protective effect of estrogren therapy ends when therapy is discontinued.

Correct Answer: The protective effect of estrogren therapy continues to prevent bone loss after therapy is discontinued.

760. (1935) Q2-2345:

Which of the following drugs is a selective estrogen receptor modulator:

1) Fosamax (alendronate sodium tablets, Merck & Co., Inc.)

3) Aredia (pamidronate disodium for injection, Novartis Pharmaceuticals Corporation)

2) Progestin

5) Alendronate sodium

4) Evista (raloxifene, Eli Lilly and Company)

A new class of selective estrogen receptor modulator acts as an antagonist in breast tissue and an agonist in bone. Raloxifene selectively stimulates estrogen receptors in bone and is an antagonist in breast tissue.

Progestin used in conjunction with estrogen opposes the action of estrogen and lowers the risk of endometrial cancer that might occur with estrogen therapy alone.

Aredia, Fosamax, and alendronate are biphosphonates that inhibit osteoclasts, thereby decreasing bone resorption.Correct

Answer: Evista (raloxifene, Eli Lilly and Company)

761. (1936) Q2-2346:

Which of the following mechanisms of bisphosphonate action occurs when a bisphosphonate is used to treat osteoporosis:

1) Increasing calcium absorption in the intestines

3) Stimulating osteoblast precursors

2) Decreasing urinary excretion of calcium

5) Increasing phosphate reabsorption in the kidney

4) Binding to hydroxyapatite crystals

Bisphosphonates are effective in the treatment of osteoporosis because they bind to the hydroxyapatite crystals and inhibit crystal resorption.

Other effects of bisphosphonates include:

Reducing production of proteins and lysosomal enzymes by osteoclasts

Reducing the formation of new bone remodeling units

Inducing osteoclast cell death

Reducing the formation of new osteoclasts

After 1 year of treatment, alendronate decreases fracture rates (hip, spine, and wrist) by 50%. Bone mass gains are modest â 2%

to 4% per year in the vertebra and 1% to 2% per year in the hip

■Correct Answer: Binding to hydroxyapatite crystals

762. (1937) Q2-2347:

Which of the following is a significant side effect of biphosphonates (e.g., alendronate):

1) Pruritus

3) Peripheral edema

2) Dizziness

5) Light sensitivity

4) Esophagitis and dyspepsia

The most significant side effect of biphosphonates is esophagitis and dyspepsia. Biphosphonates must be taken on an empty stomach with no oral intake for 30 minutes. In addition, patients should remain upright

■Correct Answer: Esophagitis and dyspepsia

763. (1938) Q2-2348:

Which of the following conditions is characterized by decreased osteoclastiCresorption of bone and cartilage with normal bone formation:

1) Type 1 osteoporosis

3) Osteopetrosis

2) Type 2 osteoporosis

5) Secondary hyperparathyroidism

4) Pagetâs disease

Osteopetrosis is a rare disorder in which there is decreased osteoclastiCresorption of bone and cartilage with normal bone formation. There are a number of different forms of the condition.

The most common form of osteopetrosis is an autosomal dominant type with mild features (adult or tarda). Patients may have mild anemia, have one or more fractures, or be asymptomatic.

The juvenile form of osteopetrosis is a severe autosomal disorder. Children have multiple fractures, severe anemia, thrombocytopenia, and hepatosplenomegaly. Effected children are also immunocompromised

■Correct Answer: Osteopetrosis

764. (1939) Q2-2349:

Which of the following is an effective medication for osteopetrosis:

1) Calcitonin

3) Fosamax (alendronate sodium tablets, Merck & Co., Inc.)

2) Alendronate

5) Interferon gamma-1

4) Calcium carbonate

Interferon gamma-1 is the only treatment for osteopetrosis that is approved by the Food and Drug Administration

■Correct Answer: Interferon gamma-1

765. (2215) Q2-2642:

Which of the following is the proper sequence when listing materials in order of increasing elastiCmodulus:

1) Cancellous bone, methylmethacrylate, cortical bone, titanium, and cobalt chrome

3) Methylmethacrylate, cancellous bone, titanium, cortical bone, and cobalt chrome

2) Cancellous bone, cortical bone, titanium, methylmethacrylate, and cobalt chrome

5) Titanium, cobalt chrome, methylmethacrylate, cancellous bone, and cortical bone

4) Titanium, cancellous bone, methylmethacrylate, cortical bone, and cobalt chrome

The proper sequence when listing common orthopediCbiomaterials in order of increasing modulus is:

ElastiCModulus Cancellous bone Polyethylene Methylmethacrylate Cortical bone Titanium alloy Stainless steel Cobalt chrome

Correct Answer: Cancellous bone, methylmethacrylate, cortical bone, titanium, and cobalt chrome

766. (2329) Q2-2784:

Which of the following areas results in latitudinal physeal enlargement:

1) Proliferative zone

3) Reserve zone

2) Provisional calcification zone

5) Perichondrial ring of La Croix

4) HypertrophiCzone

The perichondrial ring of La Croix is the source of cells which differentiate into chondrocytes and results in latitudinal physeal enlargement.

The other answers refer to specifiCgrowth plate zones which have functions. The reserve zone is for matrix production and storage. The proliferative zone is for matrix production and cellular proliferation. The hypertrophiCzone contains the zone of maturation, degeneration, and provisional calcification.

Correct Answer: Perichondrial ring of La Croix

767. (2330) Q2-2785:

The abrupt appearance of which of the following collagens heralds the onset of ossification in the physis:

1) Type I

3) Type X

2) Type VI

5) Type IX

4) Type II

The terminal hypertrophiCchondrocytes in the hypertrophiCzone produce Type X collagen. The appearance of Type X collagen heralds ossification. Remember that Type II collagen is the most abundant collagen in the hypertrophiCzone

■Correct Answer: Type X

768. (2331) Q2-2786:

Which of the following zones of the physis is involved in Salter Harris Type I and II fractures:

1) Proliferative zone

3) Reserve zone

2) Perichondrial ring

5) Zone of provisional calcification

4) Node of Ranvier

Salter Harris Type I and II fractures occur through the zone of provisional calcification or through the hypertrophiCzone. The reserve and proliferative zone remain intact and growth can proceed normal after healing of the fracture

■Correct Answer: Zone of provisional calcification

769. (2332) Q2-2787:

Which of the following is the most likely origin for the greater medullary artery:

1) Lower cervical segmental

3) Upper lumbar segmental

2) Middle thoraciCsegmental

5) Lower thoraciCsegmental

4) Upper thoraciCsegmental

The major part of the blood supply of the spinal cord is provided by the medullary or radicular arteries. The only feeder for the lower thoraciCspinal cord is the greater medullary artery or artery of Adamkiwicz (T9-T11). One should remember that in the spine, the right-sided approach is preferred to avoid the aorta and segmental artery of Adamkiwicz

■Correct Answer: Lower thoraciCsegmental

770. (2333) Q2-2788:

Enchondral ossification is responsible for mineralization in all of the following conditions except:

1) HeterotopiCbone formation

3) Callus formation during fracture healing

2) EmbryoniClong bone development

5) Perichondrial bone formation

4) Cartilage degeneration in osteoarthritis

Enchondral bone formation or ossification is bone formation on a cartilage model. Enchondral bone formation occurs in embryoniClong bone development, epiphyseal secondary center of ossification formation, callus formation during fracture healing, degenerating cartilage of osteoarthritis, calcifying cartilage tumors, and bone formed with use of demineralized bone matrix.

Intramembranous bone formation occurs in flat bone development (pelvis, clavicle, skull bones), bone formation during distraction osteogenesis, and perichondrial bone formation

■Correct Answer: Perichondrial bone formation

771. (2334) Q2-2790:

Which of the following is true concerning cancellous bone:

1) It remodels through surface cells

3) It has high density

2) It has low surface area

5) It has a low metaboliCrate and turnover

4) It is organized in osteons and lamellae

Cortical bone has a much greater density than cancellous bone. Therefore, it is stiffer and stronger. Cortical bone has a higher density than cancellous bone, is organized into osteons and lamellae, has low surface area, lower metaboliCrate than cancellous bone, remodels through osteons, and accounts for much of the structural strength of bones.

Cancellous bone has a lower density than cortical bone, has an organization of lamellar bone, has a high surface area, higher metaboliCrate than cortical bone, remodels through surface cells, and transmits forces in subchondral location.

Correct Answer: It remodels through surface cells

772. (2449) Q2-2914:

Which of the following statements is true regarding metaphyseal cortical bone formation in a child with open physes:

1) Cortical bone is formed by intramembranous bone formation.

3) Cortical bone is formed by coalescence of enchondral trabecular bone.

2) Cortical bone is formed by intramembranous and enchondral bone formation.

5) Cortical bone is formed from the groove of Ranvier.

4) Cortical bone is solely formed from the periosteal bone.

Cadet and colleagues studied the formation of cortical bone in the metaphyses of rabbits. They found that the metaphyseal cortical bone is formed by coalescence of enchondral trabecular bone.

Important points from this study include:

Metaphyseal cortical bone is formed by coalescence of enchondral trabecular bone. The coalescence is formed by an increased osteoblast surface.

The increased osteoblast surface is likely caused by factors from the periosteum.

The bone that is produced by the cells in the groove of Ranvier probably does not contribute to the metaphyseal cortical bone.

Correct Answer: Cortical bone is formed by coalescence of enchondral trabecular bone.

773. (2450) Q2-2915:

Which of the following molecules influences embryoniCbone formation and fracture healing:

1) Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1)

3) Platelet derived growth factor (PDGF)

2) Transforming growth factor-beta (TGF-B)

5) Vascular endothelial growth factor (VEGF)

4) Interleukin-1 (IL-1)

Important concepts to remember regarding signaling proteins include:

Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1) influence embryoniCbone formation and fracture healing. Vascular endothelial growth factor (VEGF) plays a role in cartilage hypertrophy at the growth plate and during fracture healing.

Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF) are found in early fracture hematoma, and these factors modulate cell proliferation and differentiation.

Bone morphogenetiCprotein and interleukin 1 and 6 are expressed during cartilage formation. Correct Answer: Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1)

774. (2451) Q2-2916:

Which of the following molecules are present in a hematoma after a fracture and aid in modulating cell proliferation and differentiation:

1) Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1)

3) Interleukin-1 (IL-1)

2) Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF)

5) Vascular endothelial growth factor (VEGF)

4) Interleukin-6 (IL-6)

Important concepts to remember regarding signaling proteins include:

Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1) influence embryoniCbone formation and fracture healing. Vascular endothelial growth factor (VEGF) plays a role in cartilage hypertrophy at the growth plate and during fracture healing.

Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF) are found in early fracture hematoma, and these factors modulate cell proliferation and differentiation.

Bone morphogenetiCprotein and interleukin 1 and 6 are expressed during cartilage formation. Correct Answer: Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF)

775. (2452) Q2-2917:

Which of the following molecules play an important role in cartilage hypertrophy during growth plate development and ossification in fracture healing:

1) Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1)

3) Interleukin-1 (IL-1)

2) Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF)

5) Vascular endothelial growth factor (VEGF)

4) Interleukin-6 (IL-6)

Important concepts to remember regarding signaling proteins include:

Indian hedgehog (IHH) and core binding factor alpha 1 (Cbfa1) influence embryoniCbone formation and fracture healing. Vascular endothelial growth factor (VEGF) plays a role in cartilage hypertrophy at the growth plate and during fracture healing.

Transforming growth factor-beta (TGF-B) and platelet derived growth factor (PDGF) are found in early fracture hematoma, and these factors modulate cell proliferation and differentiation.

Bone morphogenetiCprotein and interleukin 1 and 6 are expressed during cartilage formation. Correct Answer: Vascular endothelial growth factor (VEGF)

776. (2453) Q2-2918:

All of the following factors are important to achieve primary osteonal healing during plate fixation except:

1) AnatomiCreduction

3) Adequate vascular supply

2) Rigid fixation

5) Very low strain levels

4) Moderate-to-high strain levels

In primary osteonal bone healing, osteoclasts cut channels across the bone contact sites and blood vessels, and osteoblasts fill in the gap with new bone.

To achieve osteonal healing, there must be an anatomiCreduction with rigid fixation, an adequate blood supply, and the amount of motion at the fracture site must be very small to none (very low strain levels).

Moderate-to-high strain levels occur if there is motion at the osteosynthesis site. This motion results from poor fixation (lack of rigidity) or excessive loading during the healing period. High strain levels in the gap favor the formation of granulation tissue rather than bone.

Correct Answer: Moderate-to-high strain levels

777. (2454) Q2-2919:

All of the following factors increase the rigidity of an external fixator except:

1) Increased individual pin diameter

3) Increased bone-to-rod distance

2) Increased pin number

5) Separating half pins by 45°

4) Increased pin group separation

There are many factors that increase the rigidity of an external fixator, including: Increased pin diameter

Increased pin number Decreased bone-to-rod distance Increased pin group separation Separating half pins by 45°

Increasing the bone-to-rod distance decreases the rigidity of the system. The fracture gap is also important. The fracture gap should be minimized for excellent bone apposition.

Correct Answer: Increased bone-to-rod distance

778. (2455) Q2-2920:

Which of the following graft types has both osteoinductive and osteoconductive properties:

1) Autogenous bone marrow

3) Bone morphogenetiCprotein-2 (BMP-2)

2) Coral-based hydroxyapatite bone graft substitute

5) Cancellous bone graft

4) Recombinant bone morphogenetiCprotein-7 (rhBMP-7)

Grafting materials may include osteoconductive and/or osteoinductive properties and osteoprogenitor cells.

Cancellous bone and vascularized bone graft are the only materials that have significant osteoconductive, osteoinductive, and osteoprogenitor cells.

Several materials are mainly osteoinductive. Remember the definition of osteoinductive and osteoconductive properties: Osteoinductive factors: Molecules that have the capability of inducing osteoblastiCprecursors to differentiate into mature bone

forming cells.

Osteoinductive factors (without significant osteoconductive properties) include growth factors such as BMP-2 and rhBMP-7 (OP-1, Stryker Biotech, Hopkinton, Mass) and demineralized bone matrix.

Osteoconductive factors: The ability of a porous material to provide a scaffold for new bone formation.

Osteoconductive materials (without significant osteoinductive properties) include ceramics such as coral-based hydroxyapatite graft substitutes, Norian skeletal repair system (Norian Corporation, Cupertino, Calif), and calcium sulfate pellets (Osteoset, Wright Medical Technology Inc., Arlington, Tenn).

Bone marrow has the potential of supplying osteoprogenitor cells but has little osteoinductive or osteoconductive properties. Correct Answer: Cancellous bone graft

779. (2456) Q2-2921:

Which of the following materials has mainly osteoconductive properties with little or no osteoinductive ability:

1) Autogenous bone marrow

3) Bone morphogenetiCprotein-2 (BMP-2)

2) Coral-based hydroxyapatite bone graft substitute

5) Cancellous bone graft

4) Recombinant bone morphogenetiCprotein-7 (rhBMP-7)

Grafting materials may include osteoconductive and/or osteoinductive properties and osteoprogenitor cells.

Cancellous bone and vascularized bone graft are the only materials that have significant osteoconductive, osteoinductive, and osteoprogenitor cells.

Several materials are mainly osteoinductive. Remember the definition of osteoinductive and osteoconductive properties: Osteoinductive factors: Molecules that have the capability of inducing osteoblastiCprecursors to differentiate into mature bone

forming cells.

Osteoinductive factors (without significant osteoconductive properties) include growth factors such as BMP-2 and rhBMP-7 (OP-1, Stryker Biotech, Hopkinton, Mass) and demineralized bone matrix.

Osteoconductive factors: The ability of a porous material to provide a scaffold for new bone formation.

Osteoconductive materials (without significant osteoinductive properties) include ceramics such as coral-based hydroxyapatite graft substitutes, Norian skeletal repair system (Norian Corporation, Cupertino, Calif), and calcium sulfate pellets (Osteoset, Wright Medical Technology Inc., Arlington, Tenn).

Bone marrow has the potential of supplying osteoprogenitor cells but has little osteoinductive or osteoconductive properties. Correct Answer: Coral-based hydroxyapatite bone graft substitute

780. (2457) Q2-2922:

Which of the following materials has mainly osteoinductive properties with little or no osteoconductive ability:

1) Autogenous bone marrow

3) Calcium sulfate crystals

2) Coral-based hydroxyapatite bone graft substitute

5) Cancellous bone graft

4) Recombinant bone morphogenetiCprotein-7 (rhBMP-7)

Grafting materials may include osteoconductive and/or osteoinductive properties and osteoprogenitor cells.

Cancellous bone and vascularized bone graft are the only materials that have significant osteoconductive, osteoinductive, and osteoprogenitor cells.

Several materials are mainly osteoinductive. Remember the definition of osteoinductive and osteoconductive properties: Osteoinductive factors: Molecules that have the capability of inducing osteoblastiCprecursors to differentiate into mature bone

forming cells.

Osteoinductive factors (without significant osteoconductive properties) include growth factors such as BMP-2 and rhBMP-7 (OP-1, Stryker Biotech, Hopkinton, Mass) and demineralized bone matrix.

Osteoconductive factors: The ability of a porous material to provide a scaffold for new bone formation.

Osteoconductive materials (without significant osteoinductive properties) include ceramics such as coral-based hydroxyapatite graft substitutes, Norian skeletal repair system (Norian Corporation, Cupertino, Calif), and calcium sulfate pellets (Osteoset, Wright Medical Technology Inc., Arlington, Tenn).

Bone marrow has the potential of supplying osteoprogenitor cells but has little osteoinductive or osteoconductive properties. Correct Answer: Recombinant bone morphogenetiCprotein-7 (rhBMP-7)

781. (2458) Q2-2923:

Slide 1                             Slide 2                             Slide 3

A 65-year-old man has severe foot pain. His plain radiograph is shown in Slide 1, and a needle biopsy specimen in Slides and 3. The most likely diagnosis is:

1) Coccidioidomycosis

3) Rheumatoid arthritis

2) Pigmented villonodular synovitis

5) Tuberculosus

4) Gout

Gout is caused by the deposition of monosodium urate crystals in tissues, typically around joints. Common locations of gout include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first affected location is the great toe. Gout commonly occurs inside a joint for two reasons - synovial fluid is a poorer solvent than plasma and lower temperatures (as in peripheral joints) favor crystallization.

Neutrophils ingest the crystals and release potent lysosomal enzymes. Punched lesions may be seen on radiographs in chroniCcases, and one can often see an overlying lip of cortex at the edge of the lesion.

Histologically, the tophi have several features: Acellular amorphous material

Macrophages

Foreign body giant cells

In this patient, the joint space is preserved on the plain radiographs. The biopsy specimen has the characteristiCfeatures of gout - acellular amorphous material, macrophages, and foreign body giant cells.

Correct Answer: Gout

782. (2459) Q2-2924:

Slide 1                             Slide 2                             Slide 3

A 65-year-old man has severe foot pain. His plain radiograph is shown in Slide 1, and a needle biopsy specimen in Slides 2 and

3. The most appropriate treatment for this patient is:

1) Irrigation/debridement followed by antibiotics

3) Diphosphonate therapy

2) Chemotherapy followed by wide resection

5) ArthroscopiCdebridement

4) Nonsteriodal anti-inflammatory agents

Gout is caused by the deposition of monosodium urate crystals in tissues, typically around joints. Common locations of gout include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first affected location is the great toe. Gout commonly occurs inside a joint for two reasons - synovial fluid is a poorer solvent than plasma and lower temperatures (as in peripheral joints) favor crystallization.

Neutrophils ingest the crystals and release potent lysosomal enzymes. Punched lesions may be seen on radiographs in chroniCcases, and one can often see an overlying lip of cortex at the edge of the lesion.

Histologically, the tophi have several features: Acellular amorphous material

Macrophages

Foreign body giant cells

In this patient, the joint space is preserved on the plain radiographs. The biopsy specimen has the characteristiCfeatures of gout - acellular amorphous material, macrophages, and foreign body giant cells.

The treatment of gout includes nonsteroidal anti-inflammatory drugs and medications such as allopurinol and colchicines, which lower hyperuricemia.

Correct Answer: Nonsteriodal anti-inflammatory agents

783. (2460) Q2-2925:

Slide 1                             Slide 2                             Slide 3                             Slide 4

A 60-year-old man has severe knee pain. His plain radiographs are shown in Slide 1. His T1- and T2-weighted sagittal magnetiCresonance images (MRIs) are shown in Slides 2 and 3. A biopsy specimen is shown in Slide 4. The most likely diagnosis is:

1) Coccidioidomycosis

3) Rheumatoid arthritis

2) Pigmented villonodular synovitis

5) Tuberculosus

4) Gout

Gout is caused by the deposition of monosodium urate crystals in tissues, typically around joints. Common locations of gout include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first affected location is the great toe. Gout commonly occurs inside a joint for two reasons - synovial fluid is a poorer solvent than plasma and lower temperatures (as in peripheral joints) favor crystallization.

Neutrophils ingest the crystals and release potent lysosomal enzymes. Punched lesions may be seen on radiographs in chroniCcases, and one can often see an overlying lip of cortex at the edge of the lesion.

Histologically, the tophi have several features: Acellular amorphous material

Macrophages

Foreign body giant cells

In this patient, the joint space is preserved on the plain radiographs. The MRI scans show periarticular erosions. The biopsy specimen has the characteristiCfeatures of gout - acellular amorphous material, macrophages, and foreign body giant cells.

Correct Answer: Gout

784. (2461) Q2-2926:

Slide 1                             Slide 2                             Slide 3                             Slide 4

A 60-year-old man has severe knee pain. His plain radiographs are shown in Slide 1. His T1- and T2-weighted sagittal magnetiCresonance images (MRIs) are shown in Slides 2 and 3. A biopsy specimen is shown in Slide 4. The most appropriate treatment for this patient is:

1) Irrigation/debridement followed by antibiotics

3) Diphosphonate therapy

2) Chemotherapy followed by wide resection

5) ArthroscopiCdebridement

4) Nonsteriodal anti-inflammatory agents

Gout is caused by the deposition of monosodium urate crystals in tissues, typically around joints. Common locations of gout include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first affected location is the great toe. Gout commonly occurs inside a joint for two reasons - synovial fluid is a poorer solvent than plasma and lower temperatures (as in peripheral joints) favor crystallization.

Neutrophils ingest the crystals and release potent lysosomal enzymes. Punched lesions may be seen on radiographs in chroniCcases, and one can often see an overlying lip of cortex at the edge of the lesion.

Histologically, the tophi have several features: Acellular amorphous material

Macrophages

Foreign body giant cells

In this patient, the joint space is preserved on the plain radiographs. The biopsy specimen has the characteristiCfeatures of gout - acellular amorphous material, macrophages, and foreign body giant cells.

The treatment of gout includes nonsteroidal anti-inflammatory drugs and medications such as allopurinol and colchicines, which lower hyperuricemia.

Correct Answer: Nonsteriodal anti-inflammatory agents

785. (2571) Q2-3044:

Slide 1                             Slide 2                             Slide 3

A 55-year-old man has severe wrist pain with erythema and soft tissue swelling. The plain radiograph is shown in Slide 1 and a biopsy specimen is shown in Slide 2 and Slide 3. The most likely diagnosis is:

1) SeptiCarthritis

3) Gout

2) Osteomyelitis

5) Tuberculosis

4) MetastatiClung carcinoma

The plain radiographs show a destructive lesion in the wrist in the distal radius and at the scaphotrapezial joint. The joint spaces are preserved. The histology shows the features of gout: acellular amorphous tissue, macrophages, and giant cells.

Gout is caused by the deposition of monosodium urate crystals in tissues typically around joints. Common locations include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first attack is in the great toe. Gout commonly occurs inside a joint for two reasons:

The synovial fluid is a poorer solvent than plasma

Lower temperatures (as in peripheral joints) favor crystallization

Neutrophils ingest the crystals and then release potent lysosomal enzymes. Punched lesions may be seen on radiographs in chroniCcases. One can often see an overlying lip of cortex at the edge of the lesion.

Histologically, the tophi have several features: Acellular amorphous material

Macrophages

Foreign body giant cells

Correct Answer: Gout

786. (2572) Q2-3045:

Slide 1                              Slide 2                              Slide 3

A 55-year-old man has severe wrist pain with erythema and soft tissue swelling. The plain radiograph is shown in Slide 1 and a biopsy specimen is shown in Slide 2 and Slide 3. Which of the following would be the best treatment:

1) Debridement and antibiotics

3) External beam irradiation

2) Nonsteroidal anti-inflammatory medications

5) Thumb basal joint arthroplasty

4) Wide resection and wrist fusion

The plain radiographs show a destructive lesion in the wrist in the distal radius and at the scaphotrapezial joint. The joint spaces are preserved. The histology shows the features of gout: acellular amorphous tissue, macrophages, and giant cells.

Gout is caused by the deposition of monosodium urate crystals in tissues typically around joints. Common locations include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first attack is in the great toe. Gout commonly occurs inside a joint for two reasons:

The synovial fluid is a poorer solvent than plasma

Lower temperatures (as in peripheral joints) favor crystallization

Neutrophils ingest the crystals and then release potent lysosomal enzymes. Histologically, the tophi have several features: Acellular amorphous material

Macrophages

Foreign body giant cells

The first line of treatment is nonsteroidal anti-inflammatory medications. Correct Answer: Nonsteroidal anti-inflammatory medications

787. (2573) Q2-3046:

Which of the following statements is true regarding gout:

1) Gout is more common in females than males.

3) Gout is very common in heart transplant patients on cyclosporine.

2) Urate overproduction is the most common cause.

5) Joint space destruction is an early radiographiCfinding.

4) The serum uriCacid level is always elevated in an acute attack.

Gout is caused by the deposition of monosodium urate crystals in tissues typically around joints. Common locations include the great toe, heel, ankle, and knee. In approximately 50% of patients, the first attack is in the great toe. Gout commonly occurs inside a joint for two reasons:

The synovial fluid is a poorer solvent than plasma

Lower temperatures (as in peripheral joints) favor crystallization

One should remember the following:

Gout is much more common in males (ratio of 20:1). An inability to excrete uriCacid is the primary cause.

Gout is very common in transplant patients taking cyclosporine. Serum uriCacid level is often normal in an acute attack.

Joint space is usually preserved on plain radiographs (early disease). Correct Answer: Gout is very common in heart transplant patients on cyclosporine.

788. (2574) Q2-3047:

Slide 1                             Slide 2

A 9-year-old boy has a history of multiple fractures. He presents with left leg pain following a minor fall. His anteroposterior

(Slide 1) and lateral (Slide 2) plain radiographs are shown. Which of the following is the most likely diagnosis:

1) Child abuse

3) Osteopetrosis

2) Osteomalacia (rickets)

5) Leukemia

4) Osteogenesis imperfecta

The anteroposterior and lateral radiographs show thinned cortices and a gentle S-shaped curve of the tibia. The overall alignment of the tibia, as well as the physes, is normal. These are the radiographiCfeatures of osteogenesis imperfecta.

Child abuse, osteomalacia (rickets), osteopetrosis, and leukemia must be distinguished from osteogenesis imperfecta. In child abuse, multiple fractures are at different stages of healing. Osteomalacia has widened physes and osteopetrosis has marked bone sclerosis and absence of a medullary cavity. Patients with leukemia have lytiCdestructive lesions.

In osteogenesis imperfecta, the genetiCdefect involves type I collagen. Type I collagen is made up of two alpha-1 chains and one alpha-2 chain in a triple helix. Glycine is the smallest amino acid and is crucial for coiling of the triple helix. Mutations in the

glycine chain lead to severe forms of osteogenesis imperfecta.

One should also remember the Silence classification:

Type    Inheritance      Sclera   Severity

I          AD                     Blue        Mild form, normal teeth

II        AR                     Blue        Lethal form, die early

III       AR                     Normal    Severe, progressively deforming

IV        AD                     Normal    Moderately severe

Biphosphonate therapy can be used to slow bone remodeling and increase bone mass. Correct Answer: Osteogenesis imperfecta

789. (2575) Q2-3048:

Slide 1                             Slide 2

A 9-year-old boy has a history of multiple fractures. He presents with left leg pain following a minor fall. His anteroposterior

(Slide 1) and lateral (Slide 2) plain radiographs are shown. The most likely genetiCdefect would be:

1) FGF receptor 3

3) Cartilage oligomeriCmatrix protein

2) Type I collagen

5) Type II collagen

4) Fibrillin

The anteroposterior and lateral radiographs show thinned cortices and a gentle S-shaped curve of the tibia. The overall alignment of the tibia, as well as the physes, is normal. These are the radiographiCfeatures of osteogenesis imperfecta.

In osteogenesis imperfecta, the genetiCdefect involves type I collagen. Type I collagen is made up of two alpha-1 chains and one alpha-2 chain in a triple helix. Glycine is the smallest amino acid and is crucial for coiling of the triple helix. Mutations in the

glycine chain lead to severe forms of osteogenesis imperfecta. One should also remember the Silence classification:

Type    Inheritance      Sclera   Severity

I          AD                     Blue        Mild form, normal teeth

II        AR                     Blue        Lethal form, die early

III       AR                     Normal    Severe, progressively deforming

IV        AD                     Normal    Moderately severe

Biphosphonate therapy can be used to slow bone remodeling and increase bone mass. With regard to the incorrect choices:

FGF receptor 3 is associated with achondroplasia. Fibrillin is associated with Marfan's syndrome.

Type II collagen is associated with spondyloepiphyseal dsyplasia.

Cartilage oligomeriCmatrix protein is associated with pseudoachondroplasia.  Correct Answer: Type I collagen

790. (2576) Q2-3049:

Slide 1                             Slide 2

A 9-year-old boy has a history of multiple fractures. He presents with left leg pain following a minor fall. His anteroposterior

(Slide 1) and lateral (Slide 2) plain radiographs are shown. Which of the following can be an effective pharmacologiCtreatment:

1) Diphosphonate therapy

3) CytotoxiCmulti-agent chemotherapy

2) Vitamin D and calcium

5) Growth hormone

4) SystemiCantibiotics

The anteroposterior and lateral radiographs show thinned cortices and a gentle S-shaped curve of the tibia. The overall alignment of the tibia, as well as the physes, is normal. These are the radiographiCfeatures of osteogenesis imperfecta.

In osteogenesis imperfecta, the genetiCdefect involves type I collagen. Type I collagen is made up of two alpha-1 chains and one alpha-2 chain in a triple helix. Glycine is the smallest amino acid and is crucial for coiling of the triple helix. Mutations in the

glycine chain lead to severe forms of osteogenesis imperfecta. One should also remember the Silence classification:

Type    Inheritance      Sclera   Severity

I          AD                     Blue        Mild form, normal teeth

II        AR                     Blue        Lethal form, die early

III       AR                     Normal    Severe, progressively deforming

IV        AD                     Normal    Moderately severe

Biphosphonate therapy can be used to slow bone remodeling and increase bone mass. Correct Answer: Diphosphonate therapy