Basic Science 2015

Question 1

9. Increased levels of peroxisome proliferator-activated receptor gamma 2 (PPARy2) result in increased
10. bone.
11. adipose.
12. cartilage.
13. muscle.
14. tendon or ligament.

Answer 1

2. adipose.

RECOMMENDED READINGS

Lee FY, Drissi MH, Zuscik MJ, Chen D, Nizami S, Goto H. Molecular and cell biology in orthopaedics. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science Foundations of Clinical Practice. 4th ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2013:3-42.

Takada I, Suzawa M, Matsumoto K, Kato S. Suppression of PPAR transactivation switches cell fate of bone marrow stem cells from adipocytes into osteoblasts. Ann N Y Acad Sci. 2007 Nov;1116:182-95. Epub 2007 Jul 26. Review. PubMed PMID: 17656564.

Question 2

22. What is the mechanism of the anticoagulation effect of heparin?
23. Inhibition of Factor Xa
24. Activation of antithrombin (AT) III
25. Degradation of serine proteases
26. Interference with Factors Va and VIIIa
27. Blocking of vitamin K epoxide reductase (VKOR)

Answer 2

2. Activation of antithrombin (AT) III

RECOMMENDED READINGS

Pellegrini VD. Thrombolic disease and fat embolism syndrome. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA. eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL; American Academy of Orthopaedic Surgeons. 2013:117-133.

Roehrig S, Straub A, Pohlmann J, Lampe T, Pernerstorfer J, Schlemmer KH, Reinemer P, Perzborn E. Discovery of the novel antithrombotic agent 5-chloro-N-({(5S)-2-oxo-3-[4-(3-oxomorpholin-4-yl)phenyl]- 1,3-oxazolidin-5-yl}methyl)thiophene-2-carboxamide (BAY 59-7939): an oral, direct factor Xa inhibitor. J Med Chem.2005 Sep 22;48(19):5900-8. PubMed PMID: 16161994.

Question 3

24. What is the most likely cause of a pseudotumor in a well-positioned total hip arthroplasty?
25. Loosening of the cup at the bone interface
26. Fretting and corrosion reaction from the taper
27. Adhesive wear products from polyethylene
28. Backside wear of the polyethylene liner
29. Catastrophic polyethylene failure with metal-on-metal contact

Answer 3

2. Fretting and corrosion reaction from the taper

RECOMMENDED READINGS

Cook RB, Bolland BJ, Wharton JA, Tilley S, Latham JM, Wood RJ. Pseudotumour formation due to tribocorrosion at the taper interface of large diameter metal on polymer modular total hip replacements. J Arthroplasty. 2013 Sep;28(8):1430-6. doi: 10.1016/j.arth.2013.02.009. Epub 2013 Mar 23. PubMed PMID: 23528556.

Lieberman JR ed. AAOS Comprehensive Orthopaedic Review. Rosemont, IL; American Academy of Orthopaedic Surgeons. 2009: 21.

Question 4

36. Which gait pattern is most likely associated with knee osteoarthritis progression?
37. Abductor lurch
38. Ankle-flexed short stance
39. Increased adductor moment
40. Impulse loading after heel strike
41. Anterior cruciate ligament (ACL) protective gait

Answer 4

3. Increased adductor moment

RECOMMENDED READINGS

Li J, Hosseini A, Gadikota HR, Li G. Kinesiology of the knee joint. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science Foundations of Clinical Practice. 4th ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2013:261-278.

Chehab EF, Favre J, Erhart-Hledik JC, Andriacchi TP. Baseline knee adduction and flexion moments during walking are both associated with 5 year cartilage changes in patients with medial knee osteoarthritis. Osteoarthritis Cartilage. 2014 Nov;22(11):1833-9. doi: 10.1016/j.joca.2014.08.009. Epub 2014 Aug 27. PubMed PMID: 25211281; PubMed Central PMCID: PMC4369510.

Question 5

52. What is a major controlling molecule for tendon collagen fiber size?
53. Elastin
54. Fibrillin
55. Decorin
56. Biglycan
57. Fibronectin

Answer 5

3. Decorin

RECOMMENDED READINGS

Reuther KE, Gray CF, Soslowsky LJ. Form and function of tendon and ligament. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA. eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL; American Academy of Orthopaedic Surgeons; 2013: 213-228.

Zhang G, Ezura Y, Chervoneva I, Robinson PS, Beason DP, Carine ET, Soslowsky LJ, Iozzo RV, Birk DE. Decorin regulates assembly of collagen fibrils and acquisition of biomechanical properties during tendon development. J Cell Biochem. 2006 Aug 15;98(6):1436-49. PubMed PMID: 16518859.

Question 6

61. What is the principal cause of age-related increase in articular cartilage brittleness?
62. More rapid cleavage of collagen
63. Increase in advanced glycation end products
64. Increased association of type IX collagen with type II collagen
65. Loss of matrilin 3 association with collagen fibrils
66. Type II collagen replacement with type III collagen

Answer 6

3. Increased association of type IX collagen with type II collagen

RECOMMENDED READINGS

Chubinskaya S, Malfait A-M, Wimmer MA. Form and function of articular cartilage. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA. eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2013:183-197.

Shane Anderson A, Loeser RF. Why is osteoarthritis an age-related disease? Best Pract Res Clin Rheumatol. 2010 Feb;24(1):15-26. doi: 10.1016/j.berh.2009.08.006. Review. PubMed PMID: 20129196.

Question 7

67. The muscle energy source for a marathon athlete is predominantly
68. glycogen.
69. glycogen and fatty acids.
70. glycogen and lactic acids.
71. Adenosine triphosphate (ATP) and creatine phosphate.
72. ATP, creatine phosphate, and glycogen.

Answer 7

2. glycogen and fatty acids.

RECOMMENDED READINGS

Wright A, Gharaibeh B, Huard J. Form and function of skeletal muscle. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science Foundations of Clinical Practice. 4th ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2013:229-237.

Garrett WE Jr, Best TM. Anatomy, physiology, mechanics of skeletal muscle. In: Buckwalter JA, Einhorn TA, Simon SR, eds. Orthopaedic Basic Science: Biology and Biomechanics of the Musculoskeletal System. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2000:693-716.

Question 8

72. Which molecule is most responsible for the hydration of the intervertebral disk?
73. Decorin
74. Versican
75. Aggrecan
76. Type I collagen
77. Type II collagen

Answer 8

3. Aggrecan

RECOMMENDED READINGS

Moss IL, An HS. Form and function of the intervertebral disk. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2013:253-260.

Roughley PJ. Biology of intervertebral disc aging and degeneration: involvement of the extracellular matrix. Spine (Phila Pa 1976). 2004 Dec 1;29(23):2691-9. Review. PubMed PMID: 15564918.

Question 9

84. What is the mechanism of action for denosumab in the treatment of osteoporosis?
85. Blocking the parathyroid receptor
86. Blocking the carbonic anhydrase receptor
87. Attachment to osteoprotegerin (OPG)
88. Attachment to receptor activator of nuclear factor kappa beta (RANK)
89. Inhibition of RANK ligand (RANKL)

Answer 9

5. Inhibition of RANK ligand (RANKL)

RECOMMENDED READINGS

Bukata SV, Tyler WK. Metabolic bone disease. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2013:353-364.

Yasuda H. RANKL, a necessary chance for clinical application to osteoporosis and cancer-related bone diseases. World J Orthop. 2013 Oct 18;4(4):207-17. doi: 10.5312/wjo.v4.i4.207. Review. PubMed PMID: 24147256.

Capozzi A, Lello S, Pontecorvi A. The inhibition of RANK-ligand in the management of postmenopausal osteoporosis and related fractures: the role of denosumab. Gynecol Endocrinol. 2014 Jun;30(6):403-8. doi: 10.3109/09513590.2014.892067. Epub 2014 Mar 5. PubMed PMID: 24592987.

Question 10

87. What is the function of sclerostin in adult bone homeostasis?
88. Decreases bone formation by inhibiting osteoblastogenesis
89. Decreases bone formation by promoting osteoclastogenesis
90. Decreases bone formation by inhibiting osteocytes
91. Increases bone formation by promoting osteoblastogenesis
92. Increases bone formation by inhibiting osteoclastogenesis

Answer 10

1. Decreases bone formation by inhibiting osteoblastogenesis

RECOMMENDED READINGS

Suen PK, He YX, Chow DH, Huang L, Li C, Ke HZ, Ominsky MS, Qin L. Sclerostin monoclonal antibody enhanced bone fracture healing in an open osteotomy model in rats. J Orthop Res. 2014 Aug;32(8):997-1005. doi: 10.1002/jor.22636. Epub 2014 Apr 30. PMID: 24782158.

Bukata SV, Tyler WK. Metabolic bone disease. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2013:353-364.

Question 11

100. After initial arthroplasty surgery, infection that occurs within how many days is considered a surgical-site infection?
101. 30 days
102. 45 days
103. 60 days
104. 90 days
105. 365 days

Answer 11

5. 365 days

RECOMMENDED READINGS

Salava JK, Springer BD. Orthopaedic infections. In: Cannada LK, ed. Orthopaedic Knowledge Update 11. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2014:287-306.

Mangram AJ, Horan TC, Pearson ML, Silver LC, Jarvis WR. Guideline for Prevention of Surgical Site Infection, 1999. Centers for Disease Control and Prevention (CDC) Hospital Infection Control Practices Advisory Committee. Am J Infect Control. 1999 Apr;27(2):97-132; quiz 133-4; discussion 96. PubMed PMID: 10196487.

Question 12

106. A 5-year-old boy has progressive muscle weakness. Examination reveals pseudohypertrophy of the calf and deltoid musculature and a positive Gower sign. How is this disorder most commonly inherited?
107. Non-Mendelian
108. Autosomal recessive
109. Autosomal dominant
110. X-linked dominant
111. X-linked recessive

Answer 12

5. X-linked recessive

RECOMMENDED READINGS

Babis GC, Sakellariou VI. Muscle disorders. In: Cannada LK, ed. Orthopaedic Knowledge Update 11. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2014:237-252.

Shieh PB. Muscular dystrophies and other genetic myopathies. Neurol Clin. 2013 Nov;31(4):1009-29. doi: 10.1016/j.ncl.2013.04.004. Review. PubMed PMID: 24176421.

Question 13

115. Which factor is most commonly used to stimulate cartilage regeneration in vitro?
116. Tumor necrosis factor (TNF)-alpha
117. Transforming growth factor (TGF)-beta
118. Platelet-derived growth factor (PDGF)
119. Fibroblast growth factor (FGF)
120. Insulin-like growth factor-1 (IGF-1)

Answer 13

2. Transforming growth factor (TGF)-beta

RECOMMENDED READINGS

Klatt BA, Chen A, Tuan R. Arthritis and other cartilage disorders. In: Cannada LK, ed. Orthopaedic Knowledge Update 11. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2014:207-222.

Fortier LA, Barker JU, Strauss EJ, McCarrel TM, Cole BJ. The role of growth factors in cartilage repair. Clin Orthop Relat Res. 2011 Oct;469(10):2706-15. doi: 10.1007/s11999-011-1857-3. Review. PubMed PMID: 21403984; PubMed Central PMCID: PMC3171543.

Question 14

118. Which immune cell type is involved in metal allergy associated with orthopaedic implants?
119. Mast cells
120. Dendritic cells
121. Natural killer cells
122. B lymphocytes
123. T lymphocytes

Answer 14

5. T lymphocytes

RECOMMENDED READINGS

Jacobs JJ, Urban RM, Hallab NJ, Skipor AK, Fischer A, Wimmer MA. Metal-on-metal bearing surfaces. J Am Acad Orthop Surg. 2009 Feb;17(2):69-76. PubMed PMID: 19202120.

O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL; American Academy of Orthopaedic Surgeons: 2013.

Question 15

126. Which ion and ion channel are responsible for generation of a nerve action potential?
127. Sodium ion through a voltage-gated channel
128. Sodium ion through a transmitter-gated channel
129. Potassium ion through a voltage-gated channel
130. Potassium ion through a mechanically-gated channel
131. Chloride ion through a mechanically-gated channel

Answer 15

1. Sodium ion through a voltage-gated channel

RECOMMENDED READINGS

O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL; American Academy of Orthopaedic Surgeons: 2013.

Lee DH, Claussen GC, Oh S. Clinical nerve conduction and needle electromyography studies. J Am Acad Orthop Surg. 2004 Jul-Aug;12(4):276-87. Review. PubMed PMID: 15473679.

Catterall WA. Structure and function of voltage-gated sodium channels at atomic resolution. Exp Physiol. 2014 Jan;99(1):35-51. doi: 10.1113/expphysiol.2013.071969. Epub 2013 Oct 4. Review. PubMed PMID: 24097157; PubMed Central PMCID: PMC3885250.

Question 16

134. Figure 134 is the radiograph of a 50-year-old man. Laboratory tests were performed based on these findings, and results demonstrated an elevated alkaline phosphatase level. Which cell type is abnormally altered in the underlying pathology of this disorder?
135. Osteoclasts
136. Osteoblasts
137. Osteocytes
138. Osteoprogenitor cells
139. Mesenchymal stem cells

Answer 16

1. Osteoclasts

RECOMMENDED READINGS

Ralston SH, Langston AL, Reid IR. Pathogenesis and management of Paget’s disease of bone. Lancet. 2008 Jul 12;372(9633):155-63. doi: 10.1016/S0140-6736(08)61035-1. Review. PubMed PMID: 18620951.

Kaplan FS, Singer FR. Paget’s Disease of Bone: Pathophysiology, Diagnosis, and Management. J Am Acad Orthop Surg. 1995 Nov;3(6):336-344. PubMed PMID: 10790672.

Question 17

142. A 46-year-old laborer has elbow pain for 1 year. The pain is located over the lateral aspect, and he denies any trauma. Examination reveals pain to palpation just distal to the lateral epicondyle and pain with resisted wrist extension with the elbow in extension. Where does the primary muscle involved in this disorder insert?
143. Radial styloid
144. Base of the second metacarpal
145. Base of the third metacarpal
146. Base of the fourth metacarpal
147. Base of the fifth metacarpal

Answer 17

3. Base of the third metacarpal

RECOMMENDED READINGS

Brummel J, Baker CL 3rd, Hopkins R, Baker CL Jr. Epicondylitis: lateral. Sports Med Arthrosc. 2014 Sep;22(3):e1-6. doi: 10.1097/JSA.0000000000000024. Review. PubMed PMID: 25077751.

Bunata RE, Brown DS, Capelo R. Anatomic factors related to the cause of tennis elbow. J Bone Joint Surg Am. 2007 Sep;89(9):1955-63. PubMed PMID: 17768192.

Question 18

148. Which physical examination finding is consistent with the lesion seen on the MR images shown in Figures 148a and 148b?
149. Saddle anesthesia
150. Weak great toe extension
151. Decreased patellar tendon reflex
152. Decreased Achilles tendon reflex
153. Diminished sensation over the dorsum of the foot

Answer 18

4. Decreased Achilles tendon reflex

RECOMMENDED READINGS

O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL; American Academy of Orthopaedic Surgeons: 2013.

Hoppenfeld S, Thomas H. Physical Examination of the Spine and Extremities 1st ed. East Norwalk, CT, Appleton-Century Crofts, 1976.

Question 19

153. What happens to the size and cellularity of the nucleus pulposus proportional to the intervertebral disk after birth?
154. Increase in size and cellularity
155. Increase in size and decrease in cellularity
156. Decrease in size and cellularity
157. Decrease in size and increase in cellularity
158. Size and cellularity remain constant

Answer 19

3. Decrease in size and cellularity

RECOMMENDED READINGS

O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL; American Academy of Orthopaedic Surgeons: 2013.

Urban JPG, Roberts S, Ralphs JR. The Nucleus of the Intervertebral Disc from Development to Degeneration. Amer Zool. 2000;40:53-61.

Question 20

155. What is the most common fiber type in the knee structure shown in the arthroscopic image in Figure 155?
156. Proteoglycans
157. Elastin
158. Sharpey fibers
159. Collagen type I
160. Collagen type II

Answer 20

4. Collagen type I

RECOMMENDED READINGS

Duthon VB, Barea C, Abrassart S, Fasel JH, Fritschy D, Ménétrey J. Anatomy of the anterior cruciate ligament. Knee Surg Sports Traumatol Arthrosc. 2006 Mar;14(3):204-13. Epub 2005 Oct 19. Review. PubMed PMID: 16235056.

O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL; American Academy of Orthopaedic Surgeons: 2013.

Question 21

166. How does the World Health Organization (WHO) define osteopenia based on the dual-energy x-ray absorptiometry test?
167. T-score between 0 and 1 standard deviation below the norm
168. T-score between 1 and 2.5 standard deviations below the norm
169. Z-score between 0 and 1 standard deviation below the norm
170. Z-score between 1 and 2.5 standard deviations below the norm
171. Bone mineral density below 2.5 standard deviations of the mean for a healthy 30-year-old

Answer 21

2. T-score between 1 and 2.5 standard deviations below the norm

RECOMMENDED READINGS

Blake GM, Fogelman I. Role of dual-energy X-ray absorptiometry in the diagnosis and treatment of osteoporosis. J Clin Densitom. 2007 Jan-Mar;10(1):102-10. Epub 2006 Dec 27. Review. PubMed PMID: 17289532.

Templeton K. Secondary osteoporosis. J Am Acad Orthop Surg. 2005 Nov;13(7):475-86. Review. PubMed PMID: 16272272.

Question 22

170. Hemophilia A is a genetic disorder that is transmitted by which inheritance pattern?
171. Autosomal dominant
172. Autosomal recessive
173. X-linked recessive
174. X-linked dominant
175. Mitochondrial

Answer 22

3. X-linked recessive

RECOMMENDED READINGS

Vanderhave KL, Caird MS, Hake M, Hensinger RN, Urquhart AG, Silva S, Farley FA. Musculoskeletal care of the hemophiliac patient. J Am Acad Orthop Surg. 2012 Sep;20(9):553-63. doi: 10.5435/ JAAOS-20-09-553. Review. PubMed PMID: 22941798.

Buckwalter JA, Einhorn TA, Simon SR, eds. Orthopaedic Basic Science: Biology and Biomechanics of the Musculoskeletal System. 2nd ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2000.

Question 23

176. Figures 176a through 176c are the MR images and biopsy specimen of a 42-year-old woman who has a slow-growing mass in her right knee. Which translocation is associated with this condition?
177. 11:22
178. X:18
179. 12:16
180. 12:22
181. 9:22

Answer 23

2. X:18

RECOMMENDED READINGS

Ladanyi M, Antonescu CR, Leung DH, Woodruff JM, Kawai A, Healey JH, Brennan MF, Bridge JA, Neff JR, Barr FG, Goldsmith JD, Brooks JS, Goldblum JR, Ali SZ, Shipley J, Cooper CS, Fisher C, Skytting B, Larsson O. Impact of SYT-SSX fusion type on the clinical behavior of synovial sarcoma: a multi-institutional retrospective study of 243 patients. Cancer Res. 2002 Jan 1;62(1):135-40. PubMed PMID: 11782370.

Kawai A, Woodruff J, Healey JH, Brennan MF, Antonescu CR, Ladanyi M. SYT-SSX gene fusion as a determinant of morphology and prognosis in synovial sarcoma. N Engl J Med. 1998 Jan 15;338(3):153- 60. PubMed PMID: 9428816.

Chotel F, Unnithan A, Chandrasekar CR, Parot R, Jeys L, Grimer RJ. Variability in the presentation of synovial sarcoma in children: a plea for greater awareness. J Bone Joint Surg Br. 2008 Aug;90(8):1090-6. doi: 10.1302/0301-620X.90B8.19815. PubMed PMID: 18669969.

Question 24

186. The process of reading DNA information by RNA polymerase to make specific complementary mRNA is known as
187. replication.
188. recombination.
189. translation.
190. translocation.
191. transcription.

Answer 24

5. transcription.

RECOMMENDED READINGS

Zuscik MJ, Drissi MH, Chen D, Rosier RN. Molecular and cell biology in orthopaedics. In: Einhorn TA, O’Keefe RJ, Buckwalter JA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice, 3rd ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2007:3-23.

Lieberman JR, ed. AAOS Comprehensive Orthopaedic Review. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2009:3-13.

Question 25

192. Achondroplasia is caused by a mutation in the gene encoding for fibroblast growth factor receptor 3 (FGFR3). This genetic mutation leads to 1. accumulation of the protein in the golgi. 2. gain of function of FGFR3 (turned on). 3. loss of function of FGFR3 (turned off). 4. increased production of the FGFR3 protein. 5. decreased production of the FGFR3 protein.

Answer 25

2. gain of function of FGFR3 (turned on). RECOMMENDED READINGS Morcuende JA, Alman BA. Skeletal dysplasias, connective tissue diseases, and other genetic disorders. In: Flynn JM, ed. Orthopaedic Knowledge Update 10. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2011:797-810. Sponseller PD, Ain MC. The skeletal dysplasias. In: Morrissy RT, Weinstein SL, eds. Lovell and Winter’s Pediatric Orthopaedics. Philadelphia, PA: Lippincott Williams & Wilkins; 2006:205-250.

Question 26

198. Which factor promotes inflammation-related osteolysis around orthopaedic implants? 1. Interleukin-4 (IL-4) 2. IL-6 3. Osteoprotegerin 4. Interferon (IFN) gamma 5. Transforming growth factor beta

Answer 26

2. IL-6 RECOMMENDED READINGS Yousef AA, Clohisy JC. The biological response to orthopaedic implants. In: Einhorn TA, O’Keefe RJ, Buckwalter, JA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 3rd ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2007: 365-77. Talmo CT, Shanbhag AS, Rubash HE. Nonsurgical management of osteolysis: challenges and opportunities. Clin Orthop Relat Res. 2006 Dec;453:254-64. Review. PubMed PMID: 17016218.

Question 27

203. Materials that demonstrate stress-strain behaviors that are time dependent are 1. ductile. 2. brittle. 3. isotropic. 4. anisotropic. 5. viscoelastic.

Answer 27

5. viscoelastic RECOMMENDED READINGS Lieberman JR, ed. AAOS Comprehensive Orthopaedic Review. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2009:21-28. Lu L, Kaufman KR, Yaszemski MJ. Biomechanics. In: Einhorn TA, O’Keefe RJ, Buckwalter JA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice, 3rd ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2007:49-64.

Question 28

207. The son of a man with Huntington disease is informed that he will likely develop a more severe form of the disease at a younger age than his father. This is an example of 1. anticipation. 2. DNA methylation. 3. histone deactylation. 4. loss of telomere length. 5. lyonization.

Answer 28

1. anticipation. RECOMMENDED READINGS Cook PC, Sanders JO. Genetic diseases in orthopaedics. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA, eds. Orthopaedic Basic Science: Foundations of Clinical Practice, 4th ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2013: 43-53. Martorell L, Monckton DG, Sanchez A, Lopez De Munain A, Baiget M. Frequency and stability of the myotonic dystrophy type 1 premutation. Neurology. 2001 Feb 13;56(3):328-35. PubMed PMID: 11171897. Kamsteeg EJ, Kress W, Catalli C, Hertz JM, Witsch-Baumgartner M, Buckley MF, van Engelen BG, Schwartz M, Scheffer H. Best practice guidelines and recommendations on the molecular diagnosis of myotonic dystrophy types 1 and 2. Eur J Hum Genet. 2012 Dec;20(12):1203-8. doi: 10.1038/ ejhg.2012.108. Epub 2012 May 30. PubMed PMID: 22643181; PubMed Central PMCID: PMC3499739.

Question 29

227. An inactivating mutation in the receptor for 1,25 (OH)2 vitamin D3 is associated with which disorder? 1. Paget disease 2. Hypophosphatasia 3. Renal osteodystrophy 4. Familial hypophosphatemic rickets 5. Type II vitamin D-dependent rickets

Answer 29

5. Type II vitamin D-dependent rickets RECOMMENDED READINGS Brinker MR. Basic Science: Bone. In: Miller MD, ed. Review of Orthopaedics. 3rd ed. Philadelphia, PA: WB Saunders; 2000: 1-39. Liberman U, Marx S.Vitamin D-dependent rickets. In: Favus MK (ed). Primer on the Metabolic Bone Diseases and Disorders of Mineral Metabolism, 5th ed. Washington, DC: The American Society for Bone and Mineral Research; 2003:311-316.

Question 30

237. A patient comes to you for a second opinion after undergoing surgery for a rotator cuff tear with another surgeon in your practice. Following your evaluation, you believe that surgeon error resulted in a poor outcome. What is your responsibility in reporting to the patient that this possible error may have contributed to the poor outcome? 1. You are lawfully required to disclose this information to the patient. 2. You are lawfully and ethically required to disclose this information to the patient. 3. You are ethically required to disclose this information to the patient. 4. You are ethically required to discuss this information with your partner. 5. No disclosures are required.

Answer 30

3. You are ethically required to disclose this information to the patient. RECOMMENDED READINGS Bhattacharyya T, Yeon H. "Doctor, was this surgery done wrong?" Ethical issues in providing second opinions. J Bone Joint Surg Am. 2005 Jan;87(1):223-5. PubMed PMID: 15634836. American Academy of Orthopaedic Surgeons. Second or Additional Medical Opinions in Orthopaedic Surgery. http://www.aaos.org/CustomTemplates/Content.aspx?id=22293. Accessed January 2016.

Question 31

255. A pregnant 28-year-old woman who is seen in the emergency department with a closed ankle fracture reports that she tripped and fell at home. The patient’s mother tells you that there is reason to suspect spousal abuse as a cause for the injury. The patient denies any domestic violence. What is your responsibility in reporting this possible abuse? 1. You should do nothing further because you have no proof of abuse. 2. You should investigate further by asking other family members if spousal abuse is suspected. 3. You are required to communicate this finding with the emergency department staff and social worker. 4. The patient should be encouraged to seek self-protection and consult with a social worker at the hospital. 5. To avoid disciplinary action, by law you must report this possible abuse to the authorities.

Answer 31

4. The patient should be encouraged to seek self-protection and consult with a social worker at the hospital. RECOMMENDED READINGS American Academy of Orthopaedic Surgeons: Child Abuse or Maltreatment, Elder Maltreatment, and Intimate Partner Violence (IPV): The Orthopaedic Surgeon’s Responsibilities in Domestic and Family Violence. Rosemont, IL: American Academy of Orthopaedic Surgeons. Available at http://www.aaos.org/ CustomTemplates/Content.aspx?id=22286&ssopc=1. Accessed January 2016. American Medical Association Council on Ethical and Judicial Affairs. Code of medical ethics: Opinion 2.02 – Physicians’ Obligation in Preventing, Identifying, and Treating Violence and Abuse. Available at http://www.ama-assn.org/ama/pub/physician-resources/medical-ethics/code-medical-ethics/opinion202. page?. Accessed January 2016.

Question 32

274. A thicker myelin sheath will affect nerve transmission by 1. decreasing the depolarization rate. 2. increasing the depolarization rate. 3. increasing the relative refractory period. 4. increasing the absolute refractory period. 5. increasing the speed of wave propagation.

Answer 32

5. increasing the speed of wave propagation. RECOMMENDED READINGS Jackson WM, Diao E. Peripheral nerves: form and function. In: O’Keefe RJ, Jacobs JJ, Chu CR, Einhorn TA. eds. Orthopaedic Basic Science: Foundations of Clinical Practice. 4th ed. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2013;239-251. Peters A. The effects of normal aging on myelin and nerve fibers: a review. J Neurocytol. 2002 Sep- Nov;31(8-9):581-93. Review. PubMed PMID: 14501200.