The mechanism of action of nitrogen-containing bisphosphonates is:
1) Osteoblast activation
3) Osteoclast apoptosis
2) Osteocyte activation
5) Increased production of osteoprotegerin
4) Decreased production of receptor activator of nuclear factor-kB ligand (RANKL)
The mechanism of action of nitrogen-containing bisphosphonates is inhibition of protein prenylation. These agents cause programmed cell death of the osteoclast (apoptosis).
The nitrogen-containing bisphosphonates specifically inhibit farnesyl pyrophosphatase and prevent post-translational prenylation of guanosine triphosphate-binding proteins. Nitrogen-containing bisphosphonates disrupt the ruffled border and microtubules of the osteoclast.
Diphosphonates halt the osteoclast from resorbing bone and increasing the serum calcium level by resorbing bone and releasing the inorganic matrix. Diphosphonates are contraindicated in patients with hypocalcemia because they further lower the serum calcium level.
Diphosphonates do not influence RANKL or osteoprotegerin function or production. Correct Answe Osteoclast apoptosis
952. (3531) Q2-4485:
The mechanism of action of nitrogen-containing bisphosphonates is:
1) Toxic analogs of adenosine triphosphate
3) Increased production of osteoprotegerin
2) Decreased production of receptor activator of nuclear factor-kB ligand (RANKL)
5) Inhibition of farnesyl pyrophosphatase
4) Decreased production of RANK receptor
The mechanism of action of nitrogen-containing bisphosphonates is inhibition of protein prenylation. These agents cause programmed cell death of the osteoclast (apoptosis).
The nitrogen-containing bisphosphonates specifically inhibit farnesyl pyrophosphatase and prevent post-translational prenylation of guanosine triphosphate-binding proteins. Nitrogen-containing bisphosphonates disrupt the ruffled border and microtubules of the osteoclast.
Diphosphonates halt the osteoclast from resorbing bone and increasing the serum calcium level by resorbing bone and releasing the inorganic matrix. Diphosphonates are contraindicated in patients with hypocalcemia because they further lower the serum calcium level.
Diphosphonates do not influence RANKL or osteoprotegerin function or production. Correct Answe Inhibition of farnesyl pyrophosphatase
953. (3532) Q2-4486:
All of the following are significant risk factors for osteoporosis except:
1) White race
3) Low height
2) Low body weight
5) Maternal/paternal history of a hip fracture
4) Glucocorticoid use
The most important risk factors for osteoporosis are: Increasing age (geriatric patient)
Female gender
Early menopause
White race (fair-skinned individuals) Maternal/paternal history of hip fracture Low body weight
C igarette smoking Glucocorticoid use Excessive alcohol use Low protein intake
Anticonvulsant, antidepressant use
C orrect Answer: Low height
954. (3533) Q2-4487:
Which of the following are the most significant risk factors for osteoporosis:
1) Increasing age, female gender, low body weight
3) Increasing age, black race, male gender
2) Increasing age, female gender, high body weight
5) Male gender, white race, high body weight
4) Male gender, black race, high body weight
The most important risk factors for osteoporosis are:
Increasing age (geriatric patient) Female gender
Early menopause
White race (fair-skinned individuals) Maternal/paternal history of hip fracture Low body weight
C igarette smoking Glucocorticoid use Excessive alcohol use Low protein intake
Anticonvulsant, antidepressant use
C orrect Answer: Increasing age, female gender, low body weight
955. (3534) Q2-4488:
All of the following are significant risk factors for osteoporosis except:
1) White race
3) Low height
2) Low body weight
5) Maternal/paternal history of hip fracture
4) Glucocorticoid use
The most important risk factors for osteoporosis are: Increasing age (geriatric patient)
Female gender
Early menopause
White race (fair-skinned individuals) Maternal/paternal history of hip fracture Low body weight
C igarette smoking Glucocorticoid use Excessive alcohol use Low protein intake
Anticonvulsant, antidepressant use
C orrect Answer: Low height
956. (3535) Q2-4489:
Which of the following is a significant risk factor for osteoporosis:
1) Black race
3) Low height
2) High body weight
5) High protein intake
4) Glucocorticoid use
The most important risk factors for osteoporosis are:
Increasing age (geriatric patient) Female gender
Early menopause
White race (fair-skinned individuals) Maternal/paternal history of hip fracture Low body weight
C igarette smoking Glucocorticoid use Excessive alcohol use Low protein intake
Anticonvulsant, antidepressant use
C orrect Answer: Glucocorticoid use
957. (3536) Q2-4490:
Which of the following is a significant risk factor for osteoporosis:
1) Black race
3) Low height
2) High body weight
5) Maternal/paternal history of hip fracture
4) High protein intake
The most important risk factors for osteoporosis are: Increasing age (geriatric patient)
Female gender
Early menopause
White race (fair-skinned individuals) Maternal/paternal history of hip fracture Low body weight
C igarette smoking Glucocorticoid use Excessive alcohol use Low protein intake
Anticonvulsant, antidepressant use
C orrect Answer: Maternal/paternal history of hip fracture
958. (3537) Q2-4491:
Which of the following are significant risk factors for osteoporosis:
1) Increasing age, high body weight, female gender
3) Increasing age, low body weight, white race
2) Increasing age low body weight, male gender
5) Female gender, black race, high body weight
4) Female gender, white race, high body weight
The most important risk factors for osteoporosis are:
Increasing age (geriatric patient) Female gender
Early menopause
White race (fair-skinned individuals) Maternal/paternal history of hip fracture Low body weight
C igarette smoking Glucocorticoid use Excessive alcohol use Low protein intake
Anticonvulsant, antidepressant use
C orrect Answer: Increasing age, low body weight, white race
959. (3538) Q2-4492:
Peak bone mass is typically achieved by:
1) 10 to 20 years of age
3) 30 to 40 years of age
2) 20 to 30 years of age
5) 50 to 60 years of age
4) 40 to 50 years of age
Peak bone mass is achieved when puberty ends, usually between 20 and 30 years of age. Skeletal health is dependent upon peak bone mass because bone mass declines as an individual ages.
The greatest period of bone loss is the time of estrogen withdrawal in women. A decrease in estrogen levels has several consequences, including:
Decreased renal calcium absorption
Decreased calcium absorption
C orrect Answer: 20 to 30 years of age
960. (3702) Q2-7482:
Which of the following is false concerning fibroblast growth factor receptor 3 (FGFR3) physiology and related disorders:
1) Autosomal recessive inheritance
3) 70% are new mutations
2) Gain in function mutations
5) Ligand binding results in phosphorylation of the tyrosine kinase domain
4) Receptor is active even without ligand binding
I. Important facts concerning FGFR3 physiology and disorders
A. Gain in function mutation results in achondroplasia
B. Regulates cell growth, proliferation, and differentiation
C . Ligand binding results in phosphorylation of the tyrosine kinase domain
D. Activation of the receptor limits enchondral ossification
E. Deficiency of the receptor results in elongation of the vertebral column and long bones (knockout mice) Correct Answe Autosomal recessive inheritance
961. (3703) Q2-7483:
Which of the following is true concerning fibroblast growth factor receptor 3 (FGFR3) physiology and related disorders:
1) Autosomal recessive inheritance
3) Majority of patients with achondroplasia have an inherited mutation
B. Regulates cell growth, proliferation, and differentiation
C . Ligand binding results in phosphorylation of the tyrosine kinase domain
D. Activation of the receptor limits enchondral ossification
E. Deficiency of the receptor results in elongation of the vertebral column and long bones (knockout mice) Correct Answe Receptor is active even without ligand binding
962. (3704) Q2-7484:
Which of the following is true concerning fibroblast growth factor receptor 3 (FGFR3) physiology and related disorders:
1) Autosomal recessive inheritance
3) Majority of patients with achondroplasia have an inherited mutation
B. Regulates cell growth, proliferation, and differentiation
C . Ligand binding results in phosphorylation of the tyrosine kinase domain
D. Activation of the receptor limits enchondral ossification
E. Deficiency of the receptor results in elongation of the vertebral column and long bones (knockout mice) Correct Answe Receptor activation enhances enchondral ossification
964. (3706) Q2-7486:
Which of the following is false concerning fibroblast growth factor receptor 3 (FGFR3) physiology and related disorders:
1) Autosomal dominant inheritance
3) 70% are new mutations
2) Loss in function mutations
5) Ligand binding results in phosphorylation of the tyrosine kinase domain
Which of the following is true concerning the genetics of arthritis:
1) Siblings have a 27% risk compared to spouses
3) Precocious osteoarthritis is not associated with type V collagen mutation
2) Equal risk in monozygotic twins compared to dizygotic twins
5) Distal interphalangeal joint arthritis is linked to trauma rather than a genetic foci
4) Occurs in all patients with aging hip joints
One should remember the genetic findings in patients with osteoarthritis: Siblings have a 27% risk compared to spouses
Twice as common in monozygotic twins compared to dizygotic twins Precocious osteoarthritis is associated with type V collagen mutation Does not occur universally in aging hip joints
Distal interphalangeal joint arthritis linked to a region of chromosome 2q
C orrect Answer: Siblings have a 27% risk compared to spouses
975. (3717) Q2-7497:
Which of the following disorders has a sex-linked inheritance pattern and is caused by a point mutation in the short stature homeobox-containing gene:
1) Achondroplasia
3) Diastrophic dysplasia
2) Turnerâs syndrome
5) Multiple epiphyseal dysplasia
4) C leidocranial dysplasia
There are a set of disorders with a sex-linked inheritance pattern that are most likely caused by a point mutation in the short stature homeobox gene. These disorders include:
Turnerâs syndrome
Langer mesomelic dysplasia
Leri-Weill dyschondrosteosis
The other responses refer to common disorders with well-documented genetic abnormalities:
Achondroplasia: FGFR3
Diastrophic dysplasia: DTDST (sulfate transporter gene) C leidocranial dysplasia: C BFA1
Multiple epiphyseal dysplasia: C OMP
C orrect Answer: Turnerâs syndrome
976. (3718) Q2-7498:
A mutation in which of the following genes causes a disturbance in normal limb outgrowth patterning:
1) C BFA1
3) C OL1A1
2) C OMP
5) VDR3
4) P63
P63 is an important factor in normal limb outgrowth patterning. The other factors are involved with common disorders:
C BFA1: C leidocranial dysplasia
C OMP: Multiple epiphyseal dysplasia
C OL1A1: Osteogenesis imperfecta (easy to remember type I collagen) VDR3: Osteoporosis (easy to remember vitamin D receptor)
C orrect Answer: P63
977. (3719) Q2-7499:
A prospective, randomized study of the use of intravenous bisphosphonate therapy following a hip fracture (control = no bisphosphonate; study group = annual zoledronic acid) would most likely yield the following outcome:
1) No difference in subsequent osteoporotic fractures
3) Reduction in nonvertebral fractures; no reduction in vertebral fractures
2) Reduction in vertebral fractures; no reduction in nonvertebral fractures
5) Equal death rate in the study and control groups
4) Reduction in vertebral and nonvertebral fractures
A large prospective, randomized study showed a reduction in vertebral and nonvertebral fractures when patients were treated with intravenous (IV) zoledronic acid within 90 days of a hip fracture, followed up with annual treatment.
Important points to remember about this study:
Study: Zoledronic acid (5 mg, IV) within 90 days of hip fracture and then annually (1,000 patients in each group) New fractures: 8.6% vs 13.9% (absolute risk reduction, 5.3%; relative risk reduction, 35%)
New fractures
  o   Vertebral: 1.7% vs 3.8% (P = .02)
  o   Nonvertebral: 7.6% vs 10.7% (P = .03)
  o   Hip: 2.0% vs 3.5% (relative risk 30%, not significant)   o   Divergence of fracture-free survival at 12 months BMD
  o   12 month: 2.6% vs -1.0%   o   24 month: 4.7% vs -0.7%   o   36 month: 5.5% vs -0.9% Death
  o   Hazard ratio: -0.72 (0.56 to 0.93 C I, P = .01) Adverse advents
  o   Pyrexia: 8.7% vs 3.1%   o   Myalgia: 4.9% vs 2.7%
  o   Bone pain: 3.2% vs 1.0%
C orrect Answer: Reduction in vertebral and nonvertebral fractures
978. (3720) Q2-7500:
A prospective, randomized study of the use of intravenous bisphosphonate therapy following a hip fracture (control = no bisphosphonate; study group = annual zoledronic acid) would most likely yield the following outcome:
1) Decrease in new fractures; no improvement in bone mineral density (BMD)
3) No difference in new fractures; no difference in survival
2) No difference in new fractures; no improvement in BMD
5) No difference in fracture-free survival; no difference in vertebral fractures
4) Decrease in new fractures; survival advantage
A large prospective, randomized study showed a reduction in vertebral and nonvertebral fractures when patients were treated with intravenous (IV) zoledronic acid within 90 days of a hip fracture, followed up with annual treatment.
Important points to remember about this study:
Study: Zoledronic acid (5 mg, IV) within 90 days of hip fracture and then annually (1,000 patients in each group) New fractures: 8.6% vs 13.9% (absolute risk reduction, 5.3%; relative risk reduction, 35%)
New fractures
  o   Vertebral: 1.7% vs 3.8% (P = .02)
  o   Nonvertebral: 7.6% vs 10.7% (P = .03)
  o   Hip: 2.0% vs 3.5% (relative risk 30%, not significant)   o   Divergence of fracture-free survival at 12 months BMD
  o   12 month: 2.6% vs -1.0%   o   24 month: 4.7% vs -0.7%   o   36 month: 5.5% vs -0.9% Death
  o   Hazard ratio: -0.72 (0.56 to 0.93 C I, P = .01) Adverse advents
  o   Pyrexia: 8.7% vs 3.1%   o   Myalgia: 4.9% vs 2.7%
  o   Bone pain: 3.2% vs 1.0%
C orrect Answer: Decrease in new fractures; survival advantage
979. (3721) Q2-7501:
Patients treated with zoledronic acid within 90 days of a hip fracture, followed up with annual treatment, will most likely show:
1) Decreased vertebral fractures, no difference in nonvertebral fracture, and no difference in survival
3) No difference in vertebral and nonvertebral fracture and no difference in survival
2) Decreased vertebral fractures, decreased nonvertebral fracture, and improved survival
5) Decreased fracture rate but no difference in survival or BMD
4) Improved bone mineral density (BMD) but no difference in fracture rate
A large prospective, randomized study showed a reduction in vertebral and nonvertebral fractures when patients were treated with intravenous (IV) zoledronic acid within 90 days of a hip fracture, followed up with annual treatment.
Important points to remember about this study:
Study: Zoledronic acid (5 mg, IV) within 90 days of hip fracture and then annually (1,000 patients in each group) New fractures: 8.6% vs 13.9% (absolute risk reduction, 5.3%; relative risk reduction, 35%)
New fractures
  o   Vertebral: 1.7% vs 3.8% (P = .02)
  o   Nonvertebral: 7.6% vs 10.7% (P = .03)
  o   Hip: 2.0% vs 3.5% (relative risk 30%, not significant)   o   Divergence of fracture-free survival at 12 months BMD
  o   12 month: 2.6% vs -1.0%   o   24 month: 4.7% vs -0.7%   o   36 month: 5.5% vs -0.9% Death
  o   Hazard ratio: -0.72 (0.56 to 0.93 C I, P = .01) Adverse advents
  o   Pyrexia: 8.7% vs 3.1%   o   Myalgia: 4.9% vs 2.7%
  o   Bone pain: 3.2% vs 1.0%
C orrect Answer: Decreased vertebral fractures, decreased nonvertebral fracture, and improved survival
980. (3722) Q2-7502:
Which of the following is the most common adverse event from intravenous bisphosphonate therapy:
1) Osteonecrosis of the jaw
3) Nausea and vomiting
2) Esophageal irritation and dyspepsia
5) Pruritic rash
4) Pyrexia and myalgia
A large prospective, randomized study showed a reduction in vertebral and nonvertebral fractures when patients were treated with intravenous (IV) zoledronic acid within 90 days of a hip fracture, followed up with annual treatment.
Important points to remember about this study:
Study: Zoledronic acid (5 mg, IV) within 90 days of hip fracture and then annually (1,000 patients in each group) New fractures: 8.6% vs 13.9% (absolute risk reduction, 5.3%; relative risk reduction, 35%)
New fractures
  o   Vertebral: 1.7% vs 3.8% (P = .02)
  o   Nonvertebral: 7.6% vs 10.7% (P = .03)
  o   Hip: 2.0% vs 3.5% (relative risk 30%, not significant)   o   Divergence of fracture-free survival at 12 months BMD
  o   12 month: 2.6% vs -1.0%   o   24 month: 4.7% vs -0.7%   o   36 month: 5.5% vs -0.9% Death
  o   Hazard ratio: -0.72 (0.56 to 0.93 C I, P = .01) Adverse advents
  o   Pyrexia: 8.7% vs 3.1%   o   Myalgia: 4.9% vs 2.7%
  o   Bone pain: 3.2% vs 1.0% Correct Answe Pyrexia and myalgia
981. (3723) Q2-7503:
A 65-year-old woman sustains a hip fracture following a minor fall. Which of the following treatments should be considered:
1) A. Hormone replacement therapy
3) Antiresorptive therapy
2) Intermittent parathyroid hormone therapy
5) C alcium and vitamin D supplementation and repeat bone mineral density measurement in 1 year
4) Prophylactic fixation of the contralateral hip
This patient has a new fracture. Because the fracture occurred following minor trauma, the physician should assume that this patient has an insufficiency fracture related to her osteoporosis.
Patients who sustain an osteoporotic hip fracture should be treated with antiresorptive therapy to lower the risk of a subsequent hip or vertebral fracture. A recent randomized trial showed the following:
A large prospective, randomized study showed a reduction in vertebral and nonvertebral fractures when patients were treated with intravenous (IV) zoledronic acid within 90 days of a hip fracture, followed up with annual treatment.
Important points to remember about this study:
Study: Zoledronic acid (5 mg, IV) within 90 days of hip fracture and then annually (1,000 patients in each group) New fractures: 8.6% vs 13.9% (absolute risk reduction, 5.3%; relative risk reduction, 35%)
New fractures
  o   Vertebral: 1.7% vs 3.8% (P = .02)
  o   Nonvertebral: 7.6% vs 10.7% (P = .03)
  o   Hip: 2.0% vs 3.5% (relative risk 30%, not significant)   o   Divergence of fracture-free survival at 12 months
C orrect Answer: Antiresorptive therapy
982. (3768) Q2-7550:
Which of the following biomaterials is considered inert:
1) Porous tantalum
3) Biodegradable polymeric scaffolds
2) Autologous chondrocytes
5) C obalt-chromium alloys
4) C alcium sulfate pellets
Biocompatibility refers to materials that can be implanted into the body without causing major adverse reactions. Some materials, such as cobalt chromium alloys, are essentially inert; these materials cause no reaction from the body.
Other materials might be biocompatible, but they are not inert: Porous tantalum is a metal material that grows into bone.
Autologous chondrocytes are grown in vitro and then used as filler for cartilage defects.
Biodegradable polymeric scaffolds are resorbed and new tissues are laid down upon them.
C alcium sulfate pellets are quickly resorbed over a 4- to 6-week period and new bone formation occurs either completely or incompletely.
C orrect Answer: C obalt-chromium alloys
983. (3769) Q2-7551:
Which of the following materials is biocompatible in bulk form but may cause severe soft tissue reactions and damage in particulate form:
1) Freeze-dried allograft
3) Polymethylmethacrylate
2) Fresh-frozen allograft
5) C obalt-chromium alloy
4) Ultra-high molecular weight polyethylene
Ultra-high molecular weight polyethylene is inert in bulk form but may cause severe bone loss when found in a particulate form. Wear debris that is generated at a polyethylene metal articulation is ingested by macrophages and an inflammatory response is generated. Bone resorption often results with aseptic loosening of the involved component.
C orrect Answer: Ultra-high molecular weight polyethylene
984. (3770) Q2-7552:
Which of the following describes galvanic corrosion:
1) Between the femoral head and tapered neck
3) Delamination of high-density polyethylene
2) Screw head and countersunk region of the acetabular component
5) Irradiation of high-density polyethylene in an ambient environment
4) At the interface between a plate and the screw heads
Galvanic corrosion is caused by an electrochemical potential that is created between two metals that are located in a conductive environment, such as body fluids.
Examples of galvanic corrosion include: Screw heads and a plate
Femoral head screw and barrel of a dynamic hip screw
Interlocking screws and an intramedullary nail
Galvanic corrosion can also occur within a metal if there are impurities (intergranular corrosion).
The other responses refer to:
Fretting corrosion: Between the femoral head and tapered neck
C revice corrosion: Screw head and countersunk region of the acetabular component
Oxidative degradation: Delamination of high-density polyethylene
Oxidative degradation: Irradiation of high-density polytheylene in an ambient environment
C orrect Answer: At the interface between a plate and the screw heads
985. (3771) Q2-7553:
Which of the following describes fretting corrosion:
1) Impurities within a metal implant
3) At sites of electrochemical gradients
2) At a surface defect of an implant
5) Free-radical generation during sterilization
4) Relative micromotion under load
Fretting corrosion occurs when micromotion exists between two metals in contact. One of the most common examples of fretting corrosion is micromotion between a modular femoral head and the tapered neck junction. Modular components, such as the S- ROM system (DePuy Orthopaedics Inc., Warsaw, Ind), are subject to fretting corrosion at each of the junctions.
Techniques to minimize fretting corrosion include:
Making sure the head-neck junctions are dry and clean
Eliminating micromotion but having an exact fit (ie, not mixing manufacturers)
The other responses refer to:
Galvanic corrosion: Impurities within a metal implant C revice corrosion: At a surface defect of an implant Galvanic corrosion: At sites of electrochemical gradients
Oxidative degradation: Irradiation of high-density polyethylene in an ambient environment
C orrect Answer: Relative micromotion under load
986. (3772) Q2-7554:
Which of the following describes crevice corrosion:
1) Impurities within an implant
3) Relative micromotion under load
2) At sites of an electrochemical potential
5) Differences in oxygen tension causing pH and electrolyte changes
4) Free-radical generation during air sterilization
C revice corrosion occurs at the sites of a surface defect in a metal implant. At these defects, changes in pH and electrolyte concentrations cause corrosion.
C ommon examples of crevice corrosion include:
At the interface between an uncemented acetabular component and the cancellous screws (at the contact point where the head of the screw is countersunk into the acetabular shell)
At the interface between a screw head and the plate at the point where the screw head contacts the plate
The other responses refer to:
Galvanic corrosion: Impurities within a metal implant Galvanic corrosion: At sites of electrochemical gradients Fretting corrosion: Relative micromotion under load
Oxidative degradation: Free-radical generation during air sterilization
C orrect Answer: Differences in oxygen tension causing pH and electrolyte changes
987. (3773) Q2-7555:
Which of the following has led to oxidative degradation of ultra-high molecular weight polyethylene (UHMWPE):
1) Ram extrusion
3) Sterilization in an ambient environment
2) C ompression molding
5) Sterilization with ethylene oxide
4) Direct molding
One of the most important examples of corrosion is the breakdown of ultra-high density polyethylene. Wear particles result in osteolysis and bone loss. When UHMWPE is sterilized in air, free radicals are generated and lead to oxidative degradation of the UHMWPE.
The other responses refer to:
Ram extrusion: Manufacturing method for UHMWPE C ompression molding: Manufacturing method for UHMWPE Direct molding: Manufacturing method for UHMWPE Sterilization with ethylene oxide: Alternative
C orrect Answer: Sterilization in an ambient environment
988. (3779) Q2-7561:
Which of the following statements concerning stress fractures is false:
1) Track teams have the highest incidence of stress fractures.
3) Stress fractures occur in normal bone subjected to abnormal stresses.
2) In military recruits, rates of stress fractures are gender dependent.
5) Stress fractures occur in normal bone subjected to normal stresses.
4) Stress fractures occur in sites of bone resorption due to continued loading.
The following are features of stress fractures:
A. Stress fractures most often occur from changes in an athleteâs training program.
1. Increases in intensity
2. Increases in duration
B. In military recruits, the rates are gender dependent.
1. Men â 4%
2. Women â 7%
C . Stress fractures occur in normal bone subjected to abnormal stresses.
D. Stress fractures occur in sites of bone resorption subjected to continued loading.
E. Important to know is the definition of insufficiency fractures â fractures in abnormal bone from normal stresses. Correct Answe Stress fractures occur in normal bone subjected to normal stresses.
989. (3780) Q2-7562:
Which of the following is a significant risk factor for a stress fracture:
1) Testosterone levels in men
3) Training surfaces
2) Age
5) Low calcium intake
4) Menstrual irregularity
There are a number of risk factors for stress factors:
A. Menstrual irregularity in women is perhaps the most significant risk factor.
1. Remember the terrible triad in female patients:
a. Menstrual irregularity b. Eating disorders
c. Low bone mass
B. Increase in frequency and intensity of athletic training or activity
C . C hanges in athletic training are noted in 80% of athletes surveyed who have stress fractures. D. Decreased tibial width (smaller bone size)
E. Factors that have not been found to be statistically significant include:
1. Testosterone levels in male athletes
2. Age
a. Location by age is significant, but not etiology
3. Training surfaces
4. Flexibility
5. Low calcium intake
C orrect Answer: Menstrual irregularity
990. (3781) Q2-7563:
Which of the following is a significant risk factor for a stress fracture:
1) Flexibility
3) Increase in frequency and intensity of training
2) Training surfaces
5) Testosterone levels in athletes
4) Low calcium intake
There are a number of risk factors for stress fractures:
A. Menstrual irregularity in women is perhaps the most significant risk factor.
1. Remember the terrible triad in female patients:
a. Menstrual irregularity b. Eating disorders
c. Low bone mass
B. Increase in frequency and intensity of athletic training or activity
C . C hanges in athletic training are noted in 80% of athletes surveyed who have stress fractures. D. Decreased tibial width (smaller bone size)
E. Factors that have not been found to be statistically significant include:
1. Testosterone levels in male athletes
2. Age
a. Location by age is significant, but not etiology
3. Training surfaces
4. Flexibility
5. Low calcium intake
C orrect Answer: Increase in frequency and intensity of training
991. (3782) Q2-7564:
Which of the following statements regarding plain radiographic findings of stress fractures is false:
1) Plain radiographs have a low false-negative rate.
3) Only 20% of bone scan positive foci correlate with positive radiographic findings.
2) Periosteal bone formation is a hallmark finding.
5) he âgray cortexâ may occur secondary to cortical resorption.
4) Positive radiographic findings include horizontal or linear patterns of sclerosis.
Plain radiographs have a high false-negative rate especially early in the clinical course of stress fracture.
Periosteal new bone formation is a hallmark finding.
Only 20% of bone scan positive foci correlate with positive radiographs. Positive radiographic findings include horizontal or linear patterns of sclerosis.
The âgray cortexâ may occur from increased osteoclastic resorption on the cortex. Correct Answe Plain radiographs have a low false-negative rate.
992. (3783) Q2-7565:
A patient has an early stage stress fracture (grade 1) on a technetium bone scan. The magnetic resonance image findings most likely to correlate with the bone scan are:
1) Periosteal high signal on T2; normal marrow signal on T1- and T2-weighted images
3) Periosteal high signal on T2; increased signal on T1; and normal signal on T2-weighted images
2) Normal periosteal signal; normal marrow signal on T1- and T2-weighted images
5) Normal periosteal signal; decreased marrow signal on T1; and high signal on T2-weighted images
4) Periosteal high signal on T2; normal signal on T1; and high signal on T2-weighted images
In 1995, Fredrickson and colleagues classified stress fractures into four grades based upon bone scans:
Grade 1Â Â Â Â Â Small ill-defined cortical area of mildly increased activity
Grade 2     Well-defined cortical area of moderately increased cortical activity
Grade 3Â Â Â Â Â Wide, cortical-medullary area of increased activity
Grade 4Â Â Â Â Â Transcortical area of intensely increased activity
In an early stress fracture (grade 1 bone scan criteria), a periosteal high signal on T2-weighted images and a normal marrow signal are present.C orrect Answer: Periosteal high signal on T2; normal marrow signal on T1- and T2-weighted images
993. (3784) Q2-7566:
A patient with stress fracture has a transcortical area of intense uptake on the technetium bone scan. Which of the following findings would most likely be present on the magnetic resonance imaging (MRI) scan:
1) Normal periosteal signal; normal marrow signal on T1; high marrow signal on T2
3) Normal periosteal signal on T2; low marrow signal on T1; high marrow signal on T2
2) Normal periosteal signal; low marrow signal on T1; high marrow signal on T2
5) High periosteal signal on T2; low marrow signal on T1; normal marrow signal on T2
4) High periosteal signal on T2; low marrow signal on T1; high marrow signal on T2
In 1995, Fredrickson and colleagues classified stress fractures into four grades based upon bone scans:
Grade 1     Small ill-defined cortical area of mildly increased activity Grade 2     Well-defined cortical area of moderately increased cortical                     activity
Grade 3Â Â Â Â Â Wide, cortical-medullary area of increased activity
Grade 4Â Â Â Â Â Transcortical area of intensely increased activity
In a grade 4 stress fracture, the corresponding MRI will show: High periosteal signal on T2-weighted images
Low signal on T1-weighted images, often with a liner low signal line representing the fracture line
High signal on T2-weighted images, often with a liner low signal line representing the fracture line
C orrect Answer: High periosteal signal on T2; low marrow signal on T1; high marrow signal on T2
994. (3785) Q2-7567:
A patient has a defined area of moderately increased activity in the femoral shaft consistent with a stress fracture (grade 2 by bone scan criteria). Which of the following is the corresponding finding on the magnetic resonance imaging scan:
1) Normal periosteal signal; normal marrow T1 signal; high marrow T2 signal
3) High periosteal signal; high marrow T1 signal; normal marrow T2 signal
2) Normal periosteal signal; high marrow T1 signal; high marrow T2 signal
5) High periosteal signal; normal marrow T1 signal; high marrow T2 signal
4) High periosteal signal; normal marrow T1 signal; high marrow T2 signal
In 1995, Fredrickson and colleagues classified stress fractures into four grades based upon bone scans:
Grade 1     Small ill-defined cortical area of mildly increased activity Grade 2     Well-defined cortical area of moderately increased cortical                     activity
Grade 3Â Â Â Â Â Wide, cortical-medullary area of increased activity
Grade 4Â Â Â Â Â Transcortical area of intensely increased activity
C orrect Answer: High periosteal signal; normal marrow T1 signal; high marrow T2 signal
995. (3786) Q2-7568:
Which of the following treatment methods is used for the majority of patients with a stress fracture:
1) Rest and protected weight-bearing
3) Plate fixation with bone grafting
2) Rest and electrical stimulation
5) Intramedullary rod fixation
4) Plate fixation without bone grafting
The majority of stress fractures are treated with rest and protected weight-bearing. When the patient rests, strain on the affected bone is reduced and formation exceeds resorption, leading to bone healing.
Electrical stimulation and ultrasound have not been shown to increase the rate of healing. For most stress fractures, surgery is not necessary.
C orrect Answer: Rest and protected weight-bearing
996. (3787) Q2-7569:
Which of the following stress fractures most often requires internal fixation:
1) Second metatarsal
3) Sacrum
2) Femoral shaft
5) Tension-sided femoral neck
4) C ompression-sided femoral neck
The majority of stress fractures are treated with rest and protected weight-bearing. When the patient rests, strain on the affected bone is reduced and formation exceeds resorption, leading to bone healing.
A tension-sided femoral neck stress fracture is most at risk for progression to a complete fracture and displacement. Correct Answe Tension-sided femoral neck
997. (3788) Q2-7570:
Which of the following stress fractures is the most prone to nonunion and require surgical intervention:
1) Proximal posteromedial compression
3) Anterior tibial cortex tension
2) Distal posteromedial compression
5) Medial malleolus
4) Femoral shaft compression
The majority of stress fractures are treated with rest and protected weight-bearing. When the patient rests, strain on the affected bone is reduced and formation exceeds resorption, leading to bone healing.
An anterior tibial tension stress fracture is most prone to not healing. This fracture typically occurs in the anterior cortex and appears as a horizontal lucency â the dreaded black line.
Many patients with this fracture will not heal nonoperatively and will require intramedullary rod fixation. Correct Answe Anterior tibial cortex tension
998. (3789) Q2-7571:
Which of the following activities predisposes a patient to an anterior tibial cortex stress fracture:
1) Long-distance running
3) Military recruits following long marches
2) Repetitive jumping or leaping
5) Playing tennis
4) Gymnastics
Repetitive stresses from jumping or leaping is a risk factor for anterior tibial cortex stress fractures. C orrect Answer: Repetitive jumping or leaping
999. (3794) Q2-7577:
Which of the following properties is false concerning articular cartilage:
1) Avascular (no blood vessels)
3) Alymphatic (no lymphatic vessels)
2) Aneural (no nerve fibers)
5) Self-renewing (maintenance and restoration of extracellular matrix)
4) Moderate friction on cartilage-on-cartilage motion
Important properties of articular cartilage include: Avascular (no blood vessels)
Aneural (no nerve fibers) Alymphatic (no lymphatic vessels)
Very low friction on cartilage on cartilage motion
Self-renewing (maintenance and restoration of extracellular matrix) With aging, loss of ability to maintain the extracellular matrix
C orrect Answer: Moderate friction on cartilage-on-cartilage motion
