Mahoney case III Flashcards
2 X-ray stress tests to specifically test Lisfranc’s
- abduction stress test: step off of the 2nd met intermediate cuneiform joint
- adduction stress test: 1st met-cuneiform and 2nd met cuneiform widen
What is found with the adduction and abduction stress tests?
- abduction stress test: step off of the 2nd met intermediate cuneiform joint
- adduction stress test: 1st met-cuneiform and 2nd met cuneiform widen
Osteoporosis: imaging exams for diagnosis (4)
- DXA
- VFA
- IFA
- Quantitative Ultrasound scanner
Explain: DXA- VFA- IFA -Quantitative ultrasound scanner
DXA: dual photon X-ray absoptiometry. Gold standard to assess bone mineral density and detect early osteo.
—-2 energy X-rays shot at the bone and subtract the soft tissue component
VFA: x-ray taken of the spine, looking for an old fracture of the vertebra. Patient with the correct demographic features and positive VFA or IFA means positive for osteoporosis.
IFA: same as VFA
Quantitative Ultrasound scanner: popular prescreening tool to rule out osteoporosis. Need a DXA evaluation in order to rule in
Definition of T-scores
Standard deviation that shows how much a patient’s bone density is higher or lower than the bone density of a healthy 30 year old adult
Definition of Z- score
Standard deviation that compares patient bone density to what is normal in someone in their own age and body size.
T-score: use in what patient population
T-score used in older adults such as postmenopausal women and men over 50
Z-score: use in what patient population
useful in children, teens, younger men and women still having periods
Normal T-score and Z-score
T-score: above -1 is normal
Z-score above -2 is normal
T-scores:
–normal value
– Low bone density (osteopenia)
–Osteoporosis
- Normal bone density: -1 and above
- Low bone density (osteopenia): between -1 and -2.5
- Osteoporosis: below -2.5
Non-pharmacological treatment options for osteoporosis (3)
- behavioral modifications: stop tobacco, alcohol, and caffeine consumption
- Balanced diet: adequate calcium and Vitamin D intake
- Regulatory exercise program
MOA for estrogen
control activity of osteoblasts and osteoclasts. Will keep osteoclast numbers low and low activity as well
MOA calcium
increased bone mineralization
MOA vitamin D
increases calcium absorption in the GI tract
MOA Calcitonin
hormone directly inhibits osteoclastic bone resorption
MOA bisphosphonates
bind permanently to mineralized bone surfaces and inhibit osteoclastic activity
MOA raloxifene
will inhibit trabecular and vertebral bone loss by blocking the activity of cytokines which stimulate bone resorption
Definition of FRAX
can be used as an assessment modality for the prediction of fractures on the basis of clinical risk factors
Wilson Katz: stress fracture Type I
-what will be seen on X-ray
fracture line with no evidence of endosteal callus or periosteal reaction
-will see a radiolucent line through bone
Wilson Katz: stress fracture Type II
-what will be seen on X-ray
focal sclerosis and endosteal callus (occurs in cancellous bone)
-Will see a radiosclerotic at the metaphysis (in the metaphysis of the heads and bases)
Wilson Katz: stress fracture type III
-What will be seen on X-ray
Periosteal reaction and external reaction. Will see this mainly on the shaft
-Will see a callus lump.
Wilson Katz: stress fracture type IV
mixed combo of type 1,2,3
Fundamentals of MRI physics.
TR and TE values for T1 and T2
T1: Short TR and short TE
T2:long TR and long TE
What are the fat image and water image in MRI
Fat image is T1
Water image is T2
Gadolinium and its use in MRI
it will identify acute inflammation and infection.
-Will improve visibility of inflammation, tumours, blood vessels and blood supply
What disease will Gadolinium cause (2)
- Nephrogenic systemic fibrosis
- Gadolinium retention (in the brain)
What is the “magic angle effect”
- An MRI artifact which occurs on sequences with a short TE.
- It is confined to regions of tightly bound collagen at 54.74 degrees from the main magnetic field and appears hyperintense, thus potentially being mistaken for tendinopathy
What are the 5 stages for hemorrhage
- hyperacute
- Acute(1-2days)
- Early subacute (2-7days)
- Late subacute (7-14days)
- Chronic (14-28 days)
What are the imaging characteristics of hyperacute stage
- isointense on T1 and isointense to hyperintense on T2.
- Due to intracellular oxyhaemoglobin
What are the imaging characteristics of acute stage
- T2 signal intensity drops. T1 remains intermediate to low.
- Due to intracellular deoxyhaemoglobin
What are the imaging characteristics of early subacute stage
- T1 signal gradually increases to become hyperintense.
- Due to intracellular methaemoglobin
What are the imaging characteristics of late subacute stage
-extracellular methaemoglobin leads to increase in T2 signal
What are the imaging characteristics of chronic stage
- periphery is low on T1 + T2.
- Center is isointense on T1 and hyperintense on T2.
Stages of bone healing and time line (5)
1) Inflammation (1-4days): hematoma formation
2) Induction(day 1-?)
3) Soft callus (4-4weeks)
4) Hard callus (4 weeks- 4months)
5) Remodeling(4 months-2 years)
What effect does pH and O2 have on bone healing
- pH: better when alkyline
- High O2 better early on in bone healing
- Low O2 better later on in bone healing
Hardcastle classification for Lisfranc’s injuries
Type A: Total displacement
A1: Lateral displacement
A2: Dorsoplantar displacement
Type B: Partial displacement
B1: Medial dislocation 1st met
B2: Lateral dislocation lesser mets
Type C: Divergent (1st met medially while lesser mets go laterally)
C1: 1st met displaced medially with some lesser mets laterally displaced
C2: 1st met displaced medially with all lesser mets laterally displaced
Myerson classification of Lisfranc’s injuries
Type A: Total displacement in any plane or direction
Type B1: Medial displacement of 1st met
Type B2: Lateral displacement of 1 or more lesser mets
Type C1: Partial displacement of 1st met medially and lesser mets laterally
Type C2: Total displacement with a divergent pattern with total incongruity
AP X-ray findings for Lisfranc’s ligaments
flex sign: avulsion at base of 2nd met cuneiform
step off: widening of the 1st interweb space
Oblique X-ray findings for Lisfranc’s ligaments
lateral margins of 2nd met-cuneiform and 3rd met-cuneiform should align
Lateral X-ray findings for Lisfranc’s ligaments
will look for dorsoplantar subluxation or angulation and loss of medial plantar arch
- medial plantar archis determined by medial cuneiform and 5th met
Nunley Classification of Lisfranc’s injuries (3stages)
Stage I: pain at the Lisfranc complex and were nondisplaced radiographically, but demonstrates increased uptake on bone scan.
TX-nonoperative
Stage II: M1-M2 diastasis 1-5mm greater than the uninjured foot but no loss to arch height
TX- operative
Stage III: More than 5mm M1-M2 diastasis and arch height loss
TX- operative
External bone growth stimulators (the two types)
Electrical stimulator and ultrasound stimulator
Electrical bone stimulator details
to stimulate need to use negative electric current.
-to resorb need to use positive electric current.
Ultrasonic osteogenesis stimulator detail
stimulates receptor of osteoblasts to start producing osteoprogenitor material
-not through the previously believed mechanism of mechanical stimulation
Sudeck atrophy
metabolic bone changes that occur with CRPS
Causes of Normocytic anemia (4)
Acute blood loss
Bone marrow failure
Chronic disease
Destruction (hemolysis)
Causes of Macrocytic anemia (8)
- Alcohol (liver disease)
- B12 deficiency
- Compensatory reticulocytosis
- Drug/Dysplasia
- Endocrine (hypothyroid)
- Folate deficiency/Fetus
Causes of Microcytic anemia (4)
Thalassemia
Iron deficiency
Chronic disease
Sideroblastic anemia
