Trauma

Question 1

What is the most commonly injured nerve root in Sacral fractures

Answer 1

S1/2
Denis 3 most common (60%)

28% of neurology overall with any sacral fracture

Question 2

What is the strongest construct for SI joint fixation

Answer 2

Triangular osteosynthesis > plates > Perc Screws

• involves L5 pedical Screw, screw in ilium and sacrum with bar connection between.

Question 3

Rate of AVN with hip dislocation

Answer 3

2-17% - increases with time to reduction (>12hr)

Question 4

Hip Dislocation Clang associations

Posterior
Anterior
Obturator

Answer 4

Posterior - sciatic nerve injury (10-20%)
Anterior - vascular injury
Obturator - obturator nerve palsy

Question 5

Rate of OA post-traumatic hip dislocation

Answer 5

15-20%

Up to 88% with femoral head or acetabular fracture (JAAOS)

Question 6

What is the best radiographic view for a posterior hip dislocation

Answer 6

Obturator oblique - can visualize posterior wall for #

Question 7

Are anterior or posterior femoral head dislocations more commonly associated with head #s

Answer 7

Anterior (68%)
Posterior (7%)

Question 8

Which approach to the hip has the highest rate of HO

Answer 8

Anterior approach (6-64%)

Question 9

What are the joint reactive forces across the hip in:
A) Double leg stance
B) single leg stance

Answer 9

A) 0.5x body weight
B) 4x body weight

A cane in the opposite hand can reduce single leg stance forces across the hip by 40%

Question 10

Anatomic landmarks to ID piriformis muscle in kocher langenback approach

Answer 10

1) fat overlying short ER
2) 135 degree angle to femoral shaft
3) 2cm of tendon
4) small bursa deep to short ER

Question 11

Indications for tibia plateau ORIF

Answer 11

1) articular depression 2mm-1cm
2) condylar widening >3mm
3) varus/valgus instability (not ligamentous) > 10 degrees
4) bicondylar plateau fractures

Question 12

Acceptable alignment for non-op adult tibia diaphyseal #s

Answer 12

<5 deg varus
<10 deg A/P angulation
>50% cortical apposition
<1cm shortening
<10 deg rotational alignment

Question 13

Radiographic Indications of an unstable scaphoid fracture

Answer 13

Displacement >1mm
DISI
RL > 15 deg, SL > 60 deg,
intrascaphoid > 35 deg

Question 14

Sangeorzan classification

Answer 14

Navicular fractures
1) axial plane fracture
2) dorsolateral to plantermedial fracture
3) comminution o body in Sagittal plane, forefoot laterally displaced

Question 15

Contraindications to electrical stimulation in non-union

Answer 15

Synovial paeudoarthrosis
Mobile non-unions
Fracture gap > 1cm

Question 16

Limb deformity order of correction

Answer 16

Angulation
Translation
Length
Rotation

Question 17

Critical bone defect

Answer 17

> 50% circumferential loss
2cm length lost

Question 18

Management of post traumatic segmental bone defects

Answer 18

Length(cm)

0.1-1. Shortening
0.5-3. Cancellous bone grafting
2-10. Bone transport
5-12. Free vascularized bone graft
10-30. Amputation

Question 19

Normal compartment resting pressure

Answer 19

0-4mmHg, 8-10mmHg with exertion

Question 20

Exertional compartment syndrome diagnostic criteria

Answer 20

Resting pressure >15mmHg
Immediate post exercise is >30mmHg
>15mmHg at 15min post exercise.

Question 21

Most common compartment syndrome

Answer 21

Proximal 1/3 tibia, transverse, fibula intact - 20% incidence.

Second most common is proximal 1/3 forearm #