2019 (All) Flashcards
In electrical burns, when is emergent surgical exploration required? (JAN2019)
- Compartment syndrome,
- progressive neuro dysfunction,
- vascular compromise,
- systemic unwell due to ongoing myonecrosis
Otherwise, wait 24-48 hrs for tissue demarcation before I&D (cutaneous burns grossly underestimate damage since most goes through muscle - low intrinsic resistance and larger mass)
What type of burn has the highest rate of amputation? (JAN19)
Electrical
(35-40% amputation)
- Severity of injury (Not time of I&D) biggest factor determining need for amputation
Mortality of electric current passing hand to hand VS leg to leg (JAN19)
- Hand to hand = 60% mortality
- Leg to Leg = 20% mortality
DURATION of current main factor predicting cardiac-resp arrest
What determines the amount of heat produced by electricity in the body? (JAN19)
Amount of JOULES (current squared x resistance)
- more damage or heat where current goes from low resistance (forearm) to HIGH resistance (wrist and AC fossa)
99% of current resistance in the body comes from what structure? (JAN19)
EPIDERMIS (mean 40,000 ohms….sometimes 1,000,000 - calloused palm)
Name tissue’s resistance to electrical current from highest to lowest (JAN19)
Cortical bone > cancellous bone > fat > tendon > skin > muscle > vessels > nerves
True or False?
Success rate of free flaps lower in electrical injuries (JAN19)
True
(Ofer et al. 15% flap failure occurred
within 5-21d)
Definition of hip microinstability (JAN19)
Extraphysiological hip motion that causes pain
Force needed to distract hip with labral tear (% difference) (JAN19)
60% less force to distract hip with labral tear
Intraop findings of hip instability?
Which capsuloligamentous structure does NOT insert directly on the acetabulum? (JAN19)
- Iliofemoral (ILFL)
- Pubofemoral (PFL)
- Ischiofemoral (ISFL)
Pubofemoral (PFL)
What is the strongest ligament in the body (also in hip)? (JAN19)
ILFL (Iliofemoral ligament)
What are causes of hip microinstability? (JAN19)
- (1) notable bony abnormalities or developmental dysplasia of the hip,
- (2) connective tissue disorders,
- (3) post- traumatic,
- (4) microtraumatic (ie, usu- ally associated with athletics such as ballet/ golfers, FAI may cause hip microtraumatic instability),
- (5) iatrogenic, and
- (6) idiopathic
What three PE tests (together 95% likelihood) can dx hip microinstability? (JAN19)
- HEER or Anterior Apprehension (HyperExt + ER)
- Ext-Abd-ER
- Prone ER
What are 3 general properties of stem cells? (JAN19)
- Capable of dividing and renewing themselves for a long period of time
- Unspecialized
- Capable of producing specialized cell types
Leukocyte rich or poor PRP for tx of knee OA? Lateral elbow tendinopathy?
- RCT showed that PRP more effective if:
- Leukocyte RICH in lateral elbow tendinopathy
- Leukocyte POOR in knee OA
Trick: Only RICH people play tennis
How many medial epicondyle # go to non-union? How many are symptomatic? (JAN19)
50-90% non union and 11% out of those become symptomatic
Name the 3 components of the UCL of the elbow? (JAN19)
- Anterior oblique
- Strongest, 30-90 flex, most commonly injured
- Posterior oblique
- 90-120 flex
- Transverse
What is the most common ankle fracture pattern? (JAN19)
Isolated lateral malleolus (56-65%)
What are the primary and secondary ankle stabilizers? (JAN19)
What does research say about locking vs non locking plates of the lateral malleolus ankle #? (JAN19)
Lyle et al.: No difference in complication rate or revision surgery rate at 2 yrs
between locking and non-locking plates (locking 6X more expensive)
Post op shoulder arthroplasty for fracture with pain and pseudoparalysis, what is the cause? (JAN19)
- Pain that never improved after index procedure = indolent low-grade infection
- Pain with mechanical symptoms = anterior instability
- Pain with FF and Add = posterior instability
- Pain with pseudoparalysis = RTC dysfunction
When is Subacromial decompression an option for post shoulder arthroplasty GT malunion?
Arthoscopic SA decompression successful for GT superior
displacement up to 15 mm
What is the classification for PP # around shoulder arthroplasty?
Risk factors for intraop # for revision shoulder arthroplasty? (JAN19)
- Female
- revision Of hemiarthroplasty
- Pt with instability
How many days do you hold the cultures for P. Acnes? (JAN19)
21 days (knowing that increased chance of culturing contaminants after 11 days)
What % of patients decided to live with shoulder abx spacer permanently after stage 1 revision TSA? (JAN19)
43%
How many ACL ruptures will have chondral or meniscal pathology? (FEB19)
- 50% primary ACL ruptures and
- 90% of failed reconstructions = co-existing cartilage and/or meniscal pathology.
True or False?
Lateral meniscal tear (in ACL tear) more prone to secondary injury with surgical delay
FALSE
MEDIAL MENISCAL tears most prone to secondary injury due to surgical delay
- Increase rates of chondral/meniscal injury by 1%/ month with surgical delay.
- Lateral meniscus more associated with ACL tear; However, medial meniscal tear rates
increase with time without surgery and lateral meniscal tear remain constant.
Higher rates of chondral defects after previous meniscal repair OR partial meniscectomy?
- Higher rates of chondral injury with previous partial meniscectomy (vs repair or no tear)
o Lateral meniscal repairs were more protective of chondral injury then medial.
True or false? The sacral articular cartilage is TWICE as thick as iliac cartilage in SIJ (Feb2019)
TRUE
by 60s, marked fibrosis of SIJ with almost no motion
What is the Fortin Finger test? (Feb 2019)
Palpation, max point tenderness 2 cm inferomedial to PSIS = SIJ pathology
What % of ankle sprain and # have osteochondral lesions of the talus? (Feb2019)
Ankle sprain = 50% OC lesion
ANkle # = 73% OC lesion
In PRP (Platelet rich plasma), which type has anabolic cytokines and which type has catabolic cytokines? (Feb 2019)
Leukocyte RICH PRP = Catabolic
Leukocyte POOR PRP = anabolic
TRICK: The Rich spend (catabolic) money, and the poor need to make it
What is the incidence of adjacent segment disease after ACDF? (Feb2019)
2.9%/ year after cervical fusion
Difference in progression between cervical radic vs myelopathy?
Radiculopathy = MOST cases resolve non op
Myelopathy = progressive disorder, will need sx eventually
Name the contraindications for Cervical disc arthroplasty (Feb2019)
- 3 or more levels
- cervical instability
- allergy to implants
- Active local or systemic infx
- osteoporosis or penia
- previous sx at level
- post-traumatic vertebral deformity
- FACET arthropathy
- segmental kyphotic deformity
What is the most common complication specific to CDA (cervical disc arthroplasty)? (Feb 2019)
Heterotopic Ossification (HO)
What is the leading cause of EARLY pTHA failure?
Periprosthetic #
(Severeal national joint registries show lower risk of revision surgery if use CEMENTED pTHA when pt >75 yo)
What are risk factors for PP# in THA? (Feb2019)
- > 65 yo
- female
- cementless stem
- metabolic conditions
What is the Number needed to treat with cemented THA to prevent one intraop femoral #? (Feb 2019)
NNT = 18 patients
What are the practical phases of PMMA cement? (feb2019)
- Mixing
- Waiting
- Working
- Setting
What is the working time for medium viscocity cement at 20 degrees celsius? (Feb2019)
4-7 minutes
Indication to use CEMENTED stem in THA (age)? (FEb2019)
Over 70 yo
Note less then 55 yo do better (longevity) with cementless.
Nerve and blood supply to lat dorsi? (Feb2019)
- Thoracodorsal artery
- Thoracodorsal nerve
- C5-C7
- Branch of posterior cord of brachial plexus
Lats are one of highest power generators inwhat phase of throwing? (Feb2019)
- Acceleration phase
Deadliest TBI in sports? (Feb2019)
Epidural hematomas = notorious for so-called lucid intervals, mental clarity followed
by extreme neurologic decompensation
§ Subdural hematomas = DEADLIEST in highschool/college football, 79% of brain
injury –related deaths
Evaluation of concussion at side line, what is more reliable? (Feb2019)
Full neuro exam and evaluation with assessment tool: Sports Concussion Assessment Tool
version 5 (SCAT5)
§ Most athletes have pre-season baseline used as a reference
o Memory assessment is MORE RELIABLE than standard orientation questions.
Most common ocular injury in what sport? (Feb2019)
From 2010-2013 – basketball accounted for most eye injuries. (22.6%), followed by baseball
and air-gun shooting.
o From abrasion to globe ruptures.
Dental trauma, what to do with tooth?
If tooth cannot be re-implanted within 5 minutes of avulsion
§ PUT IN Hank’s balanced salt solution (celle and tissue culture solution = best
solution)
§ WHOLE MILK is another option (similar pH and osmolality as the mouth).
§ If water or saliva used – tooth needs to be implanted within 20 minutes.
§ If > 60 min, small chance of saving tooth since death of periodontal ligament cells.
§ Some advocate to put back in mouth (chocking hazard)
Most common cardiac cause of death in <35 yo? (Feb2019)
Most COMMON causes of cardiac death in athletes < 35 yo is hypertrophic cardiomyopathy
(26%), commotion cordis “blow to heart” (20%) and anomalous coronary arteries (14%)
o Most COMMON causes of cardiac death in athletes > 35 yo, is acquired atherosclerotic
coronary artery disease.
Asymptomatic RTC tears in 60 yo? 80yo? % (March2019)
DEGENERATIVE ROTATOR CUFF TEARS: REFINING SURGICAL
INDICATIONS BASED ON NATURAL HISTORY DATA (MARCH 1,
2019)
Asymptomatic RTC tears present in
20% of 60yo and 80% of 80yo.
Most important risk factor of supraspinatus degeneration? (March2019)
Most important predictor of SUPRA degen = disruption of
anterior supra insertion
(anterior cable)
§ Most important predictor of INFRA degen = larger tear size
Supraspinatus insertion = 12.6 mm
o Infraspinatus insertion = 32.7 mm
RTC healing in relation to location of musculotendinous junction? (March2019)
Tashjian et al., tendon healing was 92% when musculutendinous junction was LATERAL to
glenoid compared to 56% if medial to glenoid.
Risk of tear enlargement in RTC tear and management?
Advantages of UKA? (March 2019)
Adv of UKA: less-invasive surgical
exposure, preservation of native bone
stock, retention of cruciate ligs, lower
perioperative morbidity, enhanced
postop recovery, improved pt
satisfaction.
o Biomechanics more closely
resembles native knee function,
improved dynamic
proprioception and postural
control.
o Cost effective
Difference in outcome of Mobile bearing vs fixed bearing UKA? (March 2019)
In vivo meta-analysis = lower revision rates ATTRIBUTABLE to wear in MB at 5 and 10 yrs f/u
(12% revision in FB vs zero in MB), higher rates of aseptic loosening in MB, higher rates of OA
progression in FB, dislocation accounted for 11% of failures in MB…BUT no difference in
clinical outcomes, PROM, overall revision rates.
What is the most common cause of UKA revision?
Australian registry (46,094 UKAs)
§ 14.6% UKA revision at 10 years and 21% at 15 years
§ Aseptic loosening MOST COMMON indication for revision (43.5%)
§ Progression of OA (29%) and unexplained pain (9.5%)
Most prevalent risk factor in necrotizing infections? (March2019)
Epidemiology and Risk Factors:
o Diabetes mellitus is the MOST prevalent
risk factor and present in 71% of
infections.
o IVDU another predisposing factor in
43% of patients.
o Others: smoking, trauma, prior MRSA,
chronic hepatitis C, HIV/AIDS, chronic
illness, increasing age, NSAID use,
exposure to persons infected with Group A Strep.
What does MRS produce that results in muscle necrosis? (March2019)
MRSA = produce PANTON-VALENTINE LEUKOCIDIN
which causes muscle necrosis
Abx for nec fasc? (March2019)
Antibiotics:
o Broad-spectrum empiric abx should be administered at presentation (pip tazo)
o + Clindamycin or carbapenem
o + Vanco or linezolid (MRSA coverage)
o Antiribosomal agents recommended: (ie CLINDAMYCIN)
§ Limit toxin production
§ Enhance effectiveness of cell wall antimicrobial agents
Most important modifiable factor for outcome in nec fasc? (March 2019)
Surgical delay is the single most important modifiable factor contributing to mortality. (don’t
transfer, operate)
Abx for aquatic open wounds/injuries? (march 2019)
Fresh water:
§ Aeromonas hydrophila (can
cause necrotizing infections)
§ Ceftazidime 2g IV q8h (3
rd
gen cephalosporin) or
fluoroquinolone
o Salt water:
§ Vibrio violaceum (Gulf of mexico)
• Can be very aggressive, cause necrotizing infections
§ Chromobacterium violaceum (Western Pacific)
Shewanella species (Mediterranean)
§ Ceftazidime + Doxycycline 100 mg IV/PO q12h (to cover Vibrio)
o Broad spectrum abx empirically
Tx for envenomization by aquatic animal? (March 2019)
Puncture wounds = raise suspicion for envenomization
§ Hot water immersion with 45 degrees Celsius water for all envenomization wounds x 30-90
minutes or until pain subside.
§ Venom from stingrays, scorpionfish, stonefish, lionfisk, sea urchins, catfisk, and weever fish
are all HEAT LABILE.
Classification of scapular notching in rTSA? (March2019)
Alcoholism dx questionnaire? Which is more sensitive? (March 2019)
CAGE questionnaire: cutting down,
anooyance by criticism, guilty feeling,
eye-openers
o AUDIT (Alcohol Use Disorders
Identification Test): superior
sensitivity and specificity and PPV
compared to CAGE. ** especially in
elderly pt.
Serologic alteration with chronic alcohol use (\> 8/day)? (March2019)
Serologic alteration with chronic
alcohol use (> 8/day)
§ Elevated carbohydrate-deficient
transferrin
§ Macrocytosis
§ Elevated GGT
§ Elevated liver enzymes
Symptoms of alcohol withdrawal? What is PAWS?
Risk of osteolysis with HXLPE? (March2019)
Highly-cross-linked polyethylene (HXLPE)
reduced incidence of osteolysis by 92%.
§ Conventional poly (0.22 mm/ yr wear
rate) vs 0.04 mm/yr in HXLPE.
§ Incidence of clinically important
osteolysis (>1.5 cm
2
) was zero in
HXLPE.
What has the greatest effect on biologic response to wear debris? (March 2019)
SIZE HAS GREATEST EFFECT on biologic response
Particle < 7 micrometers ingested by macrophages and lead to release of cytokines included tumor
necrosis factor ALPHA and interleukin 1 and 6.
Most notable risk factor involved in osteolysis? (March 2019)
Most notable transcription factor implicated in osteolyssis activation is nuclear factor kbeta.
o Activation of macrophage/ osteoblasts = release of receptor activator of nuclear factor kB ligand =
binds to osteoclast receptor = stimulating bone resorption and granuloma formation.
Classification of THA osteolysis? (March 2019)
Saleh and Gross Classification:
§ Type 1: no notable loss of bone stock
§ Type 2: Contained defect
§ Type 3: Uncontained defect with <50% of acetabulum involved (one column involved)
§ Type 4: Uncontained defect with ?50% loss of both columns
§ Type 5: pelvic discontinuity
Limb bud orientation influences (3)? (March 2019)
Limb bud orientation under 3 influences:
1. Apical ectodermal ridge
• Prox to distal development
2. Zone of polarizing activity (ZPA)
• Produces sonic hedgehog (Shh) protein -
directs anterior vs posterior orientation (ie
radioulnar or tibfib)
3. Wnt signaling pathway
• Secreted by dorsal limb bud –
dorsoventral development
Most common classification for congenital tibial deficiency? Most common type?
- Jones classification
- Type 1A (complete absence with hypoplastic med fem condyle) MOST COMMON (46%)
Type 2 (distal absence) 2nd most common 21%
Gene involved in congenital tibial deficiency? (March2019)
NO specific gene
• Suggested autosomal-dominant
inheritance with incomplete
penetrance
• Possible 5kb deletion within DNA of
Shh repressor Gli3 protein
§ Shh pathway in syndromic forms
Associated conditions with congenital tibial deficiency? (March2019)
Associated Pathology:
o Congenital hip dislocation – MOST COMMON
o Coxa valga – 2nd
o PFFD – 3
rd
o Vertebral malformation
Concentration of lead for plumbism? (April 2019)
Plumbism (lead poisoning)
o Neurotoxicity in adults >18 ugdL, in children >5 ugdL
Most common nerve injury in UE GSW? (April2019)
Peripheral Nerve Injury
• Median nerve most commonly injury (32.3%)
• Spontaneous nerve recovery of 69%
o 4-8 mths for injuries above elbow
o 3-7 mths for injuries below elbow
• Author recommends: surgical exploration when associated with a vascular injury or another
indication for surgery
o Otherwise observe nerve for signs of return of function for at least 3 months
o Baseline EMG/NCS at 6 weeks, repeat at 3-4 mths
o Irreversible muscle reinnervation by 12-18 mths – need to consider
Most common benign tumor of the shoulder? (april2019)
Osteochondroma
Charcot shoulder most common caused by… (April2019)
Neuropathic Shoulder (Charcot Arthropathy) • Most commonly due to cervical synringomyelia
• Most common primary malignancy of bone? (April2019)
Multiple Myeloma
• Most common primary malignancy of bone (2x osteosarcoma), age >55 yrs
Most common coracoid primary malignancy? (April2019)
Chondrosarcoma
4 clinical finding that raises suspicion for ST sarcoma? (April2019)
4 key clinical findings – raise suspicion for soft-tissue sarcoma
o Firm, deep to fascia, >5 cm, non-tender
When should you consider a glenoid augmentation in rTSA? (March 2019)
Decreased scapular neck length (SNL) leads to increased
rates of notching.
§ SNL measured from lateral column to articular
glenoid surface on TRUE AP (Grashey AP) approx..
10 mm.
§ Larger in Caucasian males
o ***When performing rTSA on SNL < 9mm should
have glenoid augmentation (bone graft or augment)
Describe ways to decrease scapular notching (March 2019)
Glenosphere placement:
§ Glenosphere extension (hang) below the inferior glenoid = greatest impingement-free
adduction angle.
§ No notching bserved with an overhang of > 3.5 mm regardless of concentric vs eccentric
design.
o Glenosphere Design:
§ Lateralized believed to more closely replicate a physiologic centre of rotation and decrease
notching
§ Augment or autograft (hemoral head) or allograf (femoral neck most closely resembles shape
of glenoid pear-shape)
§ Larger diameter glenosphere = more stable, improve impingement free ROM and decreases
notching. (ie 42 mm better then 36 mm)
Humeral Implant design:
§ Decrease neck shaft angle (more varus) = more offset laterally.
Minimum f/u to determine presence of notching (scapula)? (April2019)
24 months
Incidence of Fat emboli? (April2019)
FE syndrome itself lower incidence – largest
clinical study shoes 0.9% incidence
o More common in LE fracture, closed
fracture – femur most common
o Most common in males, and in ages
10-40 yrs
• Paediatrics – much lower incidence of FES
o However Duchenne muscular
dystrophy – high rate of FES 1-20%
Fat emboli triad (April 2019)
FE syndrome triad = respiratory distress, neurologic symptoms, petechial rash
Diagnostic criteria for fat emboli (Gurd)? (April 2019)
Complications post THA for postraumatic OA
Complication rate compared to THA for primary OA?
Overall higher rate of complications compared to THA for primary OA
• Higher risk of infection, blood loss, need for transfusion
• Higher rate of dislocation à deficient GT/abductor mechanism, implant positioning
o Consider using larger diameter femoral head, dual mobility
• HO prophylaxis indicated if prior HO present (indomethacin, radiation therapy)
• Sciatic nerve injury more common after post-traumatic conversion THA
Indications for bracing in Scheuerman kyphosis (April 2019)
Bracing – for small, flexible curves
(<55-80 deg, 40% passive correction)
o Brace wear recommended for 16-23 hours/day
o Reports of up to 50% reduction in kyphosis – however some loss of
correction after termination of brace treatment