Basic Science 2016

Question 1

9. When skeletal muscle myofibrils are activated through neural pathways, which muscle fibres is recruited first?

1. Type IIA
2. Type IIB
3. Fast Glycolytic
4. Oxidative Glycolytic
5. Slow Oxidative

Answer 1

5. Slow Oxidative

Question 2

22. Which biochemical, that is associated with maintenance of at the articular cartilage phenotype, is most important during growth and development?

1. Decorin
2. Matrilin
3. Parathyroid-related protein (PTHrP)
4. 1,24 dihydroxycholicaliferol
5. Carlitalge Oligometric Protein (COMP)

Answer 2

3. Parathyroid-related protein (PTHrP)

Question 3

24. Which anterior cruciate ligament (ACL) graft type has the most tensile stiffness?

1. Bone-patellar tendon-bone
2. Quadriceps tendon
3. Quadrupled hamstring
4. Tibialis Anterior
5. Achilles Tendon

Answer 3

1. Bone-patellar tendon-bone

Question 4

36. During the course of intervertebral disk degeneration and enzymatic degradation, the molecular please that plays a predominant role in disk degeneration is:

1. Biglycan
2. Collagen II propeptide
3. Fibronectin Fragmentation
4. the G3 terminal domain of the core protein of aggrecan
5. the thrombospodin portion of cartilage oligometric protein

Answer 4

3. Fibronectin Fragmentation

Question 5

52. Which immune cell type is involved in innate immunity?

1. Killer T Cells
2. Helper T Cells
3. Natural Killer (NK) Cells
4. Plasma Cells
5. Memory B Cells

Answer 5

3. Natural Killer (NK) Cells

Question 6

61. What is the maximum length that can be bridged by a nerve conduit when repairing a nerve gap?

1. 1cm
2. 2cm
3. 3cm
4. 4cm
5. 5cm

Answer 6

3. 3cm

Question 7

67. A 58-year-old woman has had gradually worsening weakness in her dominant hand for several weeks, now has a wrist drop. What is the site of nerve entrapment?

1. Arcade of Frosche
2. Ligament of Strutters
3. Cubital Tunnel
4. Guyon’s Canal
5. Edge of Lacterus Fibrosus

Answer 7

1. Arcade of Frosche

Question 8

72. Figure 72 is the MR image of a torn structure consisting primarily of which collagen type?

1. I
2. II
3. IV
4. VI
5. X

Answer 8

1. Type I Collagen

Question 9

84. Three months after surger, an orthopaedic surgeon is studying the postsurgical range of motion of 2 patient cohorts taht underwent total knee surgery. this is a single-surgeon study, and the patients are prospectively randomized to a cruciate-retaining knee implant anda posterior-stabilized total knee implant. The null hypothesis is that patients who recieved cruciate-retaining total knee implants would have better range of motion at 3 months. At the end of the study, it is discovered that the patients in the posterior-stabilized cohort recieved outpatient physical therapy for longer period of time. This variable is an example of

1. Selection Bias
2. Confounding
3. Follow-up Bias
4. Conflict of Interest
5. Determination Bias

Answer 9

2. Confounding

Question 10

87. A 12-year old boy who is reletively short in stature has sustained several-low-energy fractures dispite having dense-appearing bones. Radiographs reveal that his distal phalanges are short. The front and back of his head are prominent. The boys’ baby teeth arrived late, adn his permanent teeth were slow to develop. There are no cervical cords or other neurologic defects. Although his bones are denser, there is now widending of the metaphysis. The likely cause of this disorder is a genetic defect of:

1. Activin A Receptor, Type 1 (ACVR-1)
2. Integrins
3. Cathespsin K (CatK)
4. Carbonic Anhydrase
5. Chloride Channel Gene (CICN7)

Answer 10

3. Cathespsin K (CatK)

Pycnodysostosis: Lysosomal storage disesease of bone.

Signs and symptoms:

• Osteopetrosis
• Short Distal Phalanges
• Delays in suture closure of the skull (with wide fontanelle- may have small bones within the fontanelle called wormian bones)
• Prominent front and back of head
• Other abnormalities of teeth, clavicles, bones, skin and nails
• Brittle Bones

Question 11

100. Following peripheral nerve injur, distal recovery typically occurs first in:

1. Motor function
2. Proprioception
3. Sympathetic activity
4. Temperature
5. Pain perception

Answer 11

3. Pain Perception

Question 12

106. A 56-year-old woman sustained a low-energy fracture and has a bone mineral density T-score of -2.7. Othere than mild hypertension, she has no systemic disorder. She is taking amlodipine for hyper tension and clonazepam as an antiepilectic. She should be advised that:

1. Does not need testing for 45 hydroxycholecalciferol levels and that clonazepam use could be related to her osteoporosis
2. Should be tested for 25 hydroxycholecalciferol; the test finding may be normal, but clonazepam use may be relatd to her osteoporosis
3. Should be testedfor 25 hydroxycholecaliferol and that her medication sare unrelated
4. Should be tested for 1,25 hydroxycholecalciferol and that her medications are unrelated
5. Should be tested for 1,25 hydroxycholecalciferol and that both medications are known to interfere with vitamin D metabolism

Answer 12

2. Should be tested for 25 hydroxycholecaliferol; the test finding may be normal, but clonazepam use may be related to her osteoporosis

Question 13

115. A 6-year-old child was born with a fixed flexion deformity of both little finger proximal IP joints, and several other fingers have similar flexion deformities. The child has a slight waddle, so gait radiographys of the hip were obtained and coxa vara was noted. Laboratory study findings include complete blood counts, erythrocyte sedimentation rate, and rheumatoid factor are negative. A referral to a pediatrician reveals tha thte child has a cardiac rub. What is the most likely diagnosis?

1. A deficit in the EXT1 gene
2. Juvenile rheumatoid arthitis (JRA)
3. Juvenile-onset lupus erythematosus
4. Campylodactyly
5. Campylodactyly-arthropathy-coxavara-pericarditis syndrome (CACP)

Answer 13

5. Campylodactyly-arthropathy-coxavara-pericarditis syndrome (CACP)

Question 14

118. Both achondroplasia and Jansen-type metaphyseal dysplasia are examples of inherited disorders characterized by a signaling disorder of:

1. Ligand mutation interited as autosomal recessive
2. Ligand mutation interited as autosomal dominant
3. Activated receptor mutation inherited as autosomal recessive
4. Activated receptor mutation inherited as autosomal dominant
5. Activated recepor mutaiton interited as sex-linked recessive

Answer 14

4. Activated receptor mutation inherited as autosomal dominant.

Achondroplasia- mutation in Fibroblast Growth Factor Receptor 3 (FGFR3)

Jansen-type Metaphyseal Dysplasia- mutation in Parathyroid Hormone Receptor (PTHR1)

• Dwarfism
• Normal ephiphysis but disorganized metaphyseal region
• Hypercalcemia
• Hypophosphetemia
• Increased urinary calcium
• Prominent/protruding eyes
• High-arched palate
• Microagnathia
• Nephorcalcinosis
• Wide Sutures

Question 15

126. A 76-year-old man with long-standing degenerative joitn disease of his right hip has developed a contracture of that hip. He walks witha characteristic crouched posture. To maintain his center of mass while walking in a straight line, he compensates by:

1. ​Keepnig his contralateral hip extended
2. Swinging his arms in a widened stance
3. Dorsiflexion his ipsilateral foot
4. Flexing his ipsilateral knee
5. Increasing lumbar kyphosis

Answer 15

4. Flexing his ipsilateral knee.

Question 16

134. A 22-year-old woman has a reletively low-energy distal radius fracture. She takes no medications and is in good health, but her vitamin D levels are very low. Vitamin D metabolite and sclerosin levels are asses before and after 3 months of vitamin D replacement therapy to determine if therapy will improve her long-term bone health. There is an expected elevation in:

1. 25-hydroxycholecalciferol and sclerosin levels but not in 1,25-dihydroxycholecalciferol level
2. 1,25-dihydroxycholecalciferol level with a lower level of sclerosin but no effect on 25-hydroxycholecalciferol level
3. 1,25-dihydroxycholecalciferol and 25-hydroxycholecalciferol levels with a lower level of sclerosin
4. 1,25-dihydroxycholecalciferol and 25-hydroxycholecalciferol levels with a higher level of sclerosin
5. 1,25-dihydroxycholecalciferol and 25-hydroxycholecalciferol levels with no effect on level of sclerosin

Answer 16

3. 1,25-dihydroxycholecalciferol and 25-hydroxycholecalciferol levels with a lower level of sclerostin.

Sclerostin anatognizes bone formation by BMP pathway, therefore causes decreased bone formation. When gene for sclerostin is mutated, you get bone overgrowth.

Question 17

142. What is the predominant fuction of aggrecan in articular cartilage?

1. Controls collagen fibril size
2. Controls collagen spatial orientation
3. Maintains osmotic water ballance
4. Transmits mechanical forces to chondrocytes
5. Exerts swelling pressure against the restraint of collagen

Answer 17

5. Exerts swelling pressure against the restriant of collagen.

Aggrecan - aka chondroitin sulfate proteoglycan 1 or cartilage-specific proteoglycan core protein.

• provides intervertebral discs the ability to resist load
• provide osmotic properties required for normal tissue function

Question 18

148. The characteristics of the region labelled A on the stress-strain curve of a ligment as shown in figure 148 predominantly are attributed to which molecule?

1. Aggrecan
2. Fibronectin
3. Decorin
4. Elastin
5. Lubricin

Answer 18

4. Elastin

Question 19

153. Which structure is identified byt he arrow in Figure 153?

1. Semimembranosus
2. Semitendinosis
3. Gracilis
4. Popliteus
5. Sartorius

Answer 19

1. Semimembranosus

Question 20

155. To reconstruct a semental tibia defect for a patient who has sustained a gunshot wound, an orthopaedic surgeon chooses to use a freeze-dried allograft. Which popential disadvantage is associated with this type of graft?

1. Reduced torsional and bending strength compared to frozen allograft
2. Reduced compressive and tensile strength compared to frozen allograft
3. Lower shelf-life compared to fresh and frozen allograft
4. Increased immunogeniciity compared to fresh allograft
5. Loss of osteoconductive properties compared to frozen allograft

Answer 20

1. Reduced torsional and bending strength compared to frozen allograft.

Question 21

166. Ceramics and inorganic compounds often are used in orthopaedic clinical practice to fil bone defects. Their biomechanical properties are best described as?

1. Very rapid resporption and remodelling of synthetic hydroxyapetite
2. Very slow resorbption of calcium sulfate
3. Providing excellent osteoinductive properties
4. Having bioceramics tha ttypically exhibit weak compressive strength
5. Having bioceramics with larger pore size that have a better osteoconductive effect.

Answer 21

5. Having bioceramics with larger pore sizes have a better osteoconductive effect.

Osteoinductive: Materials that contains factors taht stimulate bone growth and induction of stem cells down bone-forming lineage. Examples are: Deminarlized bone matrices.

Osteoconductive: Materials that acts as a structural framework for bone growth. Examples: BMP protein.

Osteogenic: Material directly provides celsl that will produce bone-inducing primitive mesenchymal stem cells, osteoblasts and osteocytes. Examples are: autologous bone graft (fresh autograft and bone marrow aspirate)

Question 22

170. Asprin affects bleeding time by which mechanism?

1. Activiates antithrombin III
2. Blocks adenosine diphosphate (ADP) receptor on platelet membranes
3. Blocks thromboxane A2
4. Inhibits factor Xa
5. Inhibits vitamin K epoxide reductase

Answer 22

3. Blocks thromboxane A2

Question 23

176. Which abnormality causes excessive knee extension during the swing phase of gait?

1. Hip flexion weakness
2. Ankle dorsiflexion weakness
3. Hamstring contracture
4. Quadriceps spasticity
5. Quadriceps weakness

Answer 23

5. Quadriceps weakness

Question 24

186. What is the dominant contributing factor in intervertebral disk degeneration?

1. Genetics
2. Nutrition
3. Inflammation
4. Vascular supply
5. Trebeclar remodelling

Answer 24

1. Genetics

Question 25

**192. The mechanism of action for fondaparinux, a synthetic pentasacharide is via:** 1. Powerful and irreversible thrombin binding 2. Indirect inhibitoin of the clotting cascade at the level of factor X 3. Antagonism of platelet aggregation 4. Orally administered direct inhibition of activated factor X 5. direct inibition of activated factor II (thrombin)

Answer 25

2. Indirect inhibition of the clotting casacde at the level of factor X.

Question 26

**198. The Small, Integrin-Binding LIgand, N-Linked Glycoprotein (SIBLING) family of noncollagenous proteions includes osteopontin, bone sialoprotein, dentin matrix protein-1, and matrix extracellular phosphyglycoprotein. Which biomechanical characteristic is responsible for much of the function?** 1. Glycosylation of collagen 2. An arg-gly-asp (RGD) sequence 3. Control of procollagin fibril widening 4. A vitamin-K-dependent gamma-carboxylation site 5. A glycogen side chain responsible for control of fibril size

Answer 26

2. An arg-gly-asp (RGD) sequence

Question 27

**203. Which molecular loss is most associated with figure 203?** 1. Versican 2. Aggrecan 3. Hyaluronic Acid 4. Type I Collagen 5. Type II Collagen

Answer 27

2. Aggecan

Question 28

**207. Which structure(s) is/are found at the bone-tendon junction and is/are responsible for nociception?** 1. Free nerve endings 2. Golgi organs 3. Golgi apparatus 4. Pacini corpuscles 5. Ruffini Endings

Answer 28

1. Free nerve endings

Question 29

**227. One of the nonmechanical causes of osteoarthritis is the DNA methylation of metalloprotease promotor sequence. This is an example of:** 1. Anticipation 2. Epigenetic Change 3. Postranslational Change 4. Spontaneous Mutation 5. Single-nucleotide Polymorphism (SNP)

Answer 29

2. Epigenetic Change

Question 30

**237. The first bone tissue that forms in the developing long bones is intramembranous. This is initiated by a lateral-diffusion Indian hedgehog. At this point, the hypertrophic condrocytes elaborate:** 1. Sox-9 2. Osteoclastin 3. Fibroblast growth factor 3 (FGF3) 4. Vascular endothelial growth factor (VEGF) 5. Peroxisome proliferator-activated receptors gamma 2 (PPARy2)

Answer 30

4. Vascular endothelial growth factor (VEGF)

Question 31

**225. Which nuclear transcription factor is important in tendon and ligament formation?** 1. Osterix 2. CCAAT/enhancer-binding protein (C/EBP) 3. Twist 1 4. Scleraxis 5. Sclerostin

Answer 31

4. Scleraxis

Question 32

**274. Which biomaterial has the highest rate of bacterial adherance?** 1. Pure titanium 2. Stainless steel 3. Tantalum 4. Titanium Alloy 5. Silver

Answer 32

4. Titanium Alloy