Orthopedic Arithmetic
Bill Nye the Bone Guy
Trauma Llamas
Its in the doctor books!
Fee morhl fractures
Xray vision
FINAL JEOPARDY
100
A higher radius of curvature results in a more _______ bone
flatter /straighter 
100
approved for use in single level ALIF and open tibial shaft fractures
rhBMP-2
100
consequence of a starting point which is too lateral given a specific nail design/geometry
Varus
100
Name 4 intra articular metaphyses
- proximal humerus
- proximal femur
- proximal radius
- distal fibula
(if osteomyelitis is seen in these areas by definition there is an associated septic joint)
100
AO/OTA classification system designation given to the femur
3
100
injury associated with this positive xray finding
PCL injury
200
bending rigidity of a solid nail is equal to this proportion
what is radius to the 4th 
200
this metal frequently used in orthopedic implants has a modulus of elasticity that most closely approximates cortical bone
titanium
200
this technique used when reaming for a prophylactic nail decreases intramedullary pressures
Venting
200
most common level for vertebral artery to enter transverse foramen
C6
200
Age and weight in which you can consider rigid antegrade nailing compared to other methods for fixing pediatric/adolescent femur fractures
11-12yrs, >50kg (100lbs)
200
what is the distal metatarsal articular angle (DMAA)?
normal is <15 degrees
300
in the normal individual with spinopelvic harmony this is geometrically related to 2 additional radiographic parameters
PT + SS
300
mixing stainless steel and cobalt chromium implant may lead to this problem
galvanic corrosion
300
name the column and wall best evaluate in the R hip on this xray
posterior wall
anterior column
300
vascular structure at risk with piriformis entry nail
medial femoral circumflex artery
300
Compared to their geriatric counterparts, young, high energy femoral shaft fractures with associated femoral neck fractures are more likely this orientation (include classification designation)
Vertical, Pauwels III
300
What is the Southwick slip angle?
400
circle line method for calculating glenoid track
0.83D - d
400
in this stress over strain curve, the slope in the elastic zone
what is young's modulus of elasticity?
( measure of stiffness, higher measure = stiffer material)
400
% increase in metabolic cost for unilateral AKA vs control
44-47%
400
narrowest diameter thoracic and lumbar pedicles respectively
T4, L1
400
These are 3 main deforming forces in a subtrochanteric femur fracture with responsible offenders
Abduction/ER - gluteal muscles
Varus - abductors
Flexion - IP
400
slip angle
500
normal lateral distal tibial angle (aLDTA)
what is 89 degrees
500
mechanism of action of nitrogen containing bisphosnates
inhibiting farnesyl pyrophosphate synthase (FPPS), an enzyme involved in the mevalonate pathway
500
DAILY DOUBLE
only elementary acetabular fracture pattern to involve both columns
transverse
500
most accurate description of the angle B - angle A
femoral ante torsion (femoral rotation)
femoral ante torsion = angle of femoral neck relative to posterior condylar axis
femoral ante version = angle of femoral neck relative to pelvic horizontal (interischial line)
500
In the Windquist & Hansen classification of femoral shaft fracture, what separates Type II and Type III fracture patterns?
Amount of cortical contact
Type II <50%
Type III >50%
500
McGregor's Line
odontoid tip >4.5cm above indicates basilar invagination
500
name this specialized radiographic technique in imaging of the foot
Broden's view