What property of Cobalt-chromium-molybdenum alloy gives it its resistance to corrosion?
In Kaplan-Meier survival analysis, what to you do when people fail?
You calculate the survival by dividing by the remaining survivors
kaplan survival = Number subjects living at the start - number subjects died / number subjects living at the start
How do you limit the Hawthorne effect?
a) Blind the patients to the exact parameter assessed
b) Proper randomization
It is the process where human subjects of an experiment change their behavior, simply because they are being studied. This is one of the hardest inbuilt biases to eliminate or factor into the design.
What is true of X-linked hypophosphatemic rickets?
It is X linked dominant
55- During lateral approach to proximal 1/3 femur, you place a Hohmann retractor posterior and encounter arterial bleeding. Which vessel?
72- What is an example of an anisotropic material?
Anisotropic: Materials that posess different mechanical properties depending on the direction of the applied load
99- Where would you expect to find obturator nerve exiting obturator foramen?
125- How do biofilms protect bacteria from antibiotics?
Which of the following medications is used to treat RA?
All are true regarding returning to driving after orthopedic surgery EXCEPT
Which is a closed chain exercise
Distal end is fixed
Regarding the mechanical axis in the tibia, all are true except?
Which of these anticoagulation therapies postop TJA has the lowest evidence supporting its use?
Which of the following is true for patients with sickle cell?
What is the last bone to ossify? REPEAT
What is the meaning of the area under a stress strain curve? REPEAT 2012
Which is a dynamic restraint to proximal migration of the humerus?
All of the following may cause scapular winging except REPEAT
What is the limiting factor in treating obese patients?
What is true about muscle activity in mid-swing (mid stance) phase of gait? REPEAT
Technical difficulty with FCR approach to distal radius?
What muscle-tendon units are activated in the mid-swing phase of gait?
Which of the following is associated with thoracic outlet syndrome?
Watson test for SLAC
Compression is btw anterior and middle scalene
It is depression of scapula
6 risk factors for thoracic outlet syndrome
Descent of scapula (trap palsy)
Congenital bands btw 1st rib and cervical rib
Female > make
3 tests for thoracic outlet sydnrome
Adson: arm adducted+ head extended + turn to affected side
Wrights: arm abducted + ER + deep breath
Which of the following study designs will convey level IV evidence?
Level 1: RCT high quality
Level 2: Less quality RCT , retrospective study
Level 3: case control
Level 4: case series
Level 5: expert opinion
With a noncompliant patient, at what point is the physician released from responsibility?
A patient needs to undergo an elective orthopaedic procedure. Which of the following describes informed consent?
3 key elements to informed consent:
What cells produce hyaluronic acid for the synovial fluid?
type B synoviocytes: synovial lining cells
A patient is unconscious & needs emergency surgery. No family members are available. What should you do?
c) Contact the hospital legal/ethics board (& wait for their decision)
You are shown a diagram of a cross-section of the thigh at the adductor canal (similar but not identical to the one below). What muscle is the arrow pointing to?
b) Adductor longus
c) Adductor magnus
Learn cross sectional anatomy!
What is true regarding intimate partner violence?
1/6 pts in ortho clinic have experienced abuse
1/50 present as a direct concequence
Regarding a hip fracture patient on Plavix (clopidogrel), which of the following is true?
Which embryonic layer forms the vertebral body?
Which is the correct order of materials according to Young’s Modulus (from highest to lowest)?
High to low:
Which of the following describes hydrodynamic lubrication?
Elastodynamic: join motion > articular carilage.
Boosted: lubricating fluid pools in regions contained by articular surface
weeping: lubricating fluid sshifts from articular surface towards load bearign regions
What is the main blood supply to the scaphoid?
All of the following are true, EXCEPT?
All are true EXCEPT?
All the following are components of the rotator cuff interval EXCEPT?
Coracohumeral ligament that bridge the gap between supraspinatus and subscap
All are true regarding observational studies EXCEPT?
The main branch of the medial femoral circumflex artery is anterior to all of the following structures EXCEPT?
Deep branch MFCA passes behind obturator externus then it goes anterior to obturator internus/sup/inf gemellus
Perforates capsule at the level of sup gemellus
With regards to osteoporosis and proximal femur fractures, everything is true EXCEPT:
In the lateral corticospinal and spinothalamic tracts, which fibers are located on the lateral aspect of each?
Spinothalamic tract from central to peripheral: Cervical thoracic lumbar sacral
Posterior columns:med to lat > sacral > lumbar > thoracic >cervical
Guy fell off a ladder 5 weeks ago, initially had lots of shoulder and neck pain, now c/o numbness lateral arm, weak shoulder abduction, also has winging. What is the lesion? (C5 root was NOT an option).
All of the following are regarding HIT are true except.
HIT timing: fall platelets >50 usually 5-10 days after initiation of therapy
Big problem is thrombosis
What is mode of inheritance for duchennes?
What would you find with hypophosphotasia?
have low alk phos, high calcium, high phosphate
Increase in urine phosphoethanolamine: dx
All are true re: bisphosphonates in kids except?
A has slow decrease in calcium
Retrograde ejaculation caused by? Repeat from way back
the sympathetic superior hypogastric plexus anterior to L5
All of the following are potential causes of knee pain EXCEPT?
Patient with RA. Which of the following medications must be stopped pre-operatively?
c) Vitamin K
B: stop in diabetics, elderly or ppl with liver, kidney, lung disease undergoing major procedures
Which of the following allow you to become stronger during initial phase of training?
increase in muscle cross sectional area due to increase in size of muscle fibers, not due to additional muscles
Pt has MRSA. Best periop abx? High rate MRSA your hospital
What is interval for ant. Approach to hip?
Hypovolemic shock, ATP depleted. What happens intracellular?
Patient in hypovolemic shock is fluid ressuscitated with NS. What will labs show?
All of the following make up the quadrangular space except?
What is the main stabilizer to posterior shoulder translation when the shoulder is in flexion, adduction, and internal rotation?
SGHL and coracohumeral: Limit inferior translation + ER when arm adducted.......limit posterior translation when arm flexed adducted IR
MGHL: Limit ER with addcuted humeurs + Ant/post with partially abducted humerus
IGHL: Primary restraint to anterior posterior at 45-90 degrees of elevation
Shown Cross section of thigh at adductor canal. What is the arrow pointing to? Note: the diagram was essentially identical to this one from Netter’s. However, it was a left thigh, not right as shown here.
Weird question on functional loads in stable joint, all except?
Transient osteoporosis, all except
a) Usually healthy, middle-aged men
b) Usually no trauma
c) Roughly 50% of cases in the upper extremity
d) Physical exam usually reveals minimal restriction in ROM
C: occurs only in lower extremity
usually health middle aged men and pregnant women
Minimal restriction to ROM on exam
Mechanism of botox?
a) Inhibition of postsynaptic acetylcholine receptor
b) Inhibition of ACh release from presynaptic vesicles
Competitive inhibitor of presynaptic cholinergic receptors with a finite lifetime (usually lasts 2-3 months)
Most common cause of upper extremity neuropathic arthropathy?
Most common overall is diabetes
What is the most sensitive test when evaluation for musculoskeletal infection?
C-diff, all true except?
All of the following practices can prevent HIV transmission except?
What amount of force do the hip abductors need to generate to keep pelvis level in single leg stance?
Articular cartilage, all true except
Cartilage made of sulfated PG: chondroitin and keratin sulfate
Weight: 60% collagen, 35% PG
All of the following cell types are present during the inflammatory phase of bone healing EXCEPT:
Which of the following is the correct order of cartilaginous zones from metaphysis to physis?
reserve is closest to epiphysis
Which of the following are responsible for formation of verterbrae?
Mesoderm is responsible for MSK
Ectoderm is responsible for neural tube
Which of the following is the correct ranking in order of Young’s Modulus of Elasticity from Highest to Lowest?
High young smodulus means stiffer
Youngs modulus is the slope of stress strain curve
Which of the following antibiotics are appropriate for treatment of Eikenella
Corrodens due to a human bite injury?
Usually treatment is amox/clav
All of the following are true with ADH in shock EXCEPT:
Promotos mesenteric vasoconstriction of smooth muscle
Post approach to knee what is landmark?
Specifically medial sural cutaneous that leads to tibial N
Usually along with small saphenus vein
Young’s Modulus: High to low (Make list in order)
b) Cobalt Chrome
d) Cortical Bone
Hydrodynamic lubrication (old question):
Answer: This is a form of LUBRICATION in articular cartilage.
Elastohydrodynamic lubrication is the predominant mechanism during dynamic joint motion.
Hyaluronic acid is made by…
All of the following are about fiberglass compared to Plaster EXCEPT:
All of the following are true regarding cement compared to bone graft for GCT
Which of the following structures is the main landmark for the posterior approach to the popliteal fossa?
Which of the following collagen orientations are most resistant to hoop stresses in the menisci?
Peak maximum vascularity of fracture callus
Normalizes after 3-5 months
Pressure injury of tourniquet
EMG normal 1 year
Wider is better
Injury is at the level of the cuff
Which of the following is true in regards to synovial fluid?
Which nerve(s) are contained within the carotid sheath along with the Internal Jugular Vein and Common Carotid Artery?
Other structures in sheath
Internal jugular vein
COmmon carotid A
Deep cervical LN
A 16 y.o. female patient with long-standing seizure disorder has used Phenytoin (Dilantin) for many years. She is found to have osteomalacia. What is the reason?
VIT D GETS 25 FROM LIVER
Vit D gets 1 from kidney
SUn makes pre vit D to Vit D
Polyarticular sepsis is often seen with which underlying diagnosis:
Multiple septic arthritis is most often associated with which of the following disorders:
Pnemococcal pneumonia is predictor of mortality
In polyarticular septic arthritis which joints are most commonly involved (each stem had 4 choices and you needed to pick the one with all 4 right joints).
a) hip, shoulder, elbow, ankle
b) hip shoulder, knee, elbow
In necrotizing fasciitis, what is the most consistent initial symptom:
Which of the following constructs can be used by utilizing the tension band principle except:
Which of the following is true for titanium plates (LC-DCP) compared to stainless steel:
All help to increase stability for an ex-fix, except
Which is true: these are probably misworded stems but you get the gist
a) GAG are sulfated
b) Cartilage is viscoelastic
c) The annulus is viscoelastic
d) The nucleus pulposus has mainly hydrostatic pressure