2018 (All) Flashcards
List 8 factors contributing to increased wear in THA. (Patient, Surgeon, Implant, In Vivo).
- Patient
- Activity
- Age
- Surgeon
- Component position
- Fixation Mode
- Intraaritcular Debris
- Implant
- Material
- Femoral Head Size
- Modular Interfaces
- Geometry
- In vivo
- Impingement
- Microseparation
- Lubrication
- Oxidation
- Corrosion
- Fretting
- 3rd bodies
Which has the highest surface roughness?
a) Ceramic
b) UHMWPE
c) Cobalt Chrome
d) Titanium
b) UHMWPE
Which form of lubrication is most favourabel for wear?
a) Hydrodynamic
b) Boundary
c) Weeping
d) Mixed
a) Hydrodynamic - the surfaces don’t touch, separated by fluid
Describe the principle of “bedding in”.
“Bedding In” Period - increased wear rates are seen in the first million cycles of a material (approximately 1 year of loading), followed by a steady state wear.
What amount of wear (linear and volumetric) is the threshold for osteolysis from polyethelen debris?
- 0.10 mm/year linear wear
- 80mm3/year volumetric wear
Which of the following is false regarding wear characteristics in THA?
a) Standard Poly (SP) has less wear than Crosslinked Poly (XLP)
b) Revision rates for loosening/lysis are higher with SP vs XLP
c) Ceramic on poly/ceramic have the best wear rates
d) There is limited data regarding survivorship in Vitamin E poly
a) Standard Poly (SP) has less wear than Crosslinked Poly (XLP) (FALSE)
Which of the following pairs are correct regarding when to hold medications prior to elective spine surgery?
a) ASA - 3 days
b) Naproxen - 3 days
c) Clopidogrel - 5 days
d) Warfarin - 7 days
b) Naproxen - 3 days
- ASA 7 days
- Ibuprofen 24 hours
- Celebred 24 hours
- Naproxen 3 days
- Clopidogrel 7 days
- Warfarin 5 days
Role for bridging should be assessed on a case-by case basis. In the situation where a patient has just been stented, should consider delaying elective spine surgery for duration of post-stenting prophylaxis
- Pure metal stents - 6 weeks
- Drug eluting - 6 months - 1 year
List 6 strategies for minimizing blood loss in spine surgery.
- Evaluate patient medications preoperatively (hold appropriate ones like warfarin, clopidogrel)
- Cell Saver
- Hypotensive anesthesia
- Minimizing hypothermia
- TXA
- Patient positioning (avoid pressure on the abdome to avoid venous congestion of the portal system)
- Electrocautery
- Local agents (fibrin glue, collegen material, bone wax)
At which threshold of blood loss does a cell-saver become cost effective?
500cc
What are two contraindications for the use of cell-saver in spine surgery?
- Malignancy
- Infection
Which of the following is not a side effect of cell saver transfusion?
a) Transient hemoglobinuria
b) Pulmonary complications (TRALI)
c) Coagulopathy
d) Clotting
d) Clotting
List 4 methods for increasing the efficacy of cell saver use in spine surgery.
- Open tipped suction
- Wand pressure >100mmHg
- Avoid blood pooling and clotting
- Use few sponges/rinse sponges
What is the most common cause of morbidity an death in snowboarders?
a) Pilon Fractures
b) Pelvic Fractures
c) Upper Extremity Injuries
d) Head Injuries
d) Head Injuries -
- ~15 percent of all reported snowboard injury are head injuries.
- Higher morbidity and mortaliy with these injuries
What is the most common mechanism for spinal injury in skiiers?
a) Distraction Injury
b) Rotatinal Injury
c) Flexion Injury
d) Compression Injury
d) Compression Injury
- Compression type are the most common, with distraction and rotational injuries seen far less often
- Of the compresion fractures, majority (71%) are simple compression fractures, and 23% burst fractures
List 4 mechanisms for shoulder injury associated with skiing.
- Direct Impact
- Acial load on extended arm
- Resisted forced abduction
- External Rotation (results from firmly planted pole in grasp of skiier during a fall)
Which of the following is true regarding injuries sustained while skiing/snowboarding?
a) Ulnar collateral ligment injuries of the thumb are more common in snowboarders vs skiiers.
b) Wrist injuries are more common in skiiers than snowboarders.
c) ACL injuries are more common in skiiers than snowboarders.
d) The mechanism for pilon fracures in skiiers is high-energy rotation.
c) ACL injuries are more common in skiiers than snowboarders.
- Wrist injuries are more common in snowboarders vs skiiers
- Mechanism for pilon fractures is axial load.
- UCL injuries more common in skiiers due to forced abduction against the pole (skiiers thumb)
All of the below injuries are more common in snowboarders vs skiiers except?
a) ACL injuries
b) Wrist fractures
c) Ankle fractures
d) Lateral process talus fractures.
d) ACL
- Lateral process talus fractures (aka snowboarder’s fracture)
- Often missted
- ORIF when >2mm displacement in a fixable fragment (otherwise excise if too small and displaced)
- Complications associated with missed fracture
- Ostenecrosis
- Nonunion
- Subtalar OA
What are the most important structures in preventing bowstringing of flexor tendons in the fingers? The thumb?
Fingers: A2 and A4 pulley
Thumb: Oblique pulley
Name the flexor tendon injury zones. (6)
- Zone I - FDP insertin to FDS insertion
- Zone II - FDS insertion to A1 pulley
- Zone III - A1 pulley to distal transverse carpal ligment
- Zone IV - Carpal Tunnel
- Zone V - proximal transverse carpal ligament to musculotendinous junction in forearm
- Zone VI - muscle bellies
As per Strickland, what are the 6 principles of tendon repair?
- Easy placement of suture material
- Secure knots
- Smooth juction at tendon ends
- Minimial gapping at repair site
- minimial interference with tendon vascularity
- Sufficient strengthen throughout healing to apply early motion stress to tendon
- Can be achieved by:
- minimizing handling of tendon to decrease scarring and adhesisons
- Strength of repair proportional to # of core sutures and calibre crossing the tendon, use 4 or 6 core sutures
- No specific material preferred over another
- knots can be intra or extratendinous
- various suture configurations (see chart)
- core sutures should be placed 7-10 mm from the tendon edge
- Dorsal placement is biomechanically advantageous
- epitendinous sutures can be used
- shown to increase strength by 10-15%
- decrease gapping
How would you manage tendon injuries in each of the flexor tendon zones?
- Zone I
- Type 1 - retraction of proximal stump into palm
- disrupts vincular system
- repair within 7 days to avoid contracture and necrosis
- Type 2 - avulsion with retraction to the PIP
- Less disruption, not as much of a rush
- Repair within 6 weeks
- Type 3 - avulsion (often with bony fragment)
- bony fragment prevents retraction past the A4 pulley
- Direct repair if possible of the bony fragment
- Can wait up to 6 weeks, less disruption due to less distraction
- Type 4- Avulsion of FDP from a fracture fragment
- Difficult, need to repair the fracture and the tendon
- Be careful not to advance the tendon more than 1cm, to avoid quadregia effect (common muscle belly of FDP can cause laxity and inabity to completely flex other tendons if repaired too short)
- Type 5 - Distal phalanx fracture with bony avulsin of FDP
- Repair fracture and tendon
- Type 1 - retraction of proximal stump into palm
- If stump >1cm can repair tendon direction
- if stump <1cm will need to use suture anchors
In chronic situations (>6 weeks) difficult to restore function, may requrie DIP fusion
- Zone 2
- Brunners incisions
- Repair, do not completely release A2 pulley
- Can excise 25% of A2 and A4 pulley without funcitonal deficit
- Partial <50% can trim free ends
- >50% tendon laceration requires repair
- Repair within 7-10 days to minimize contractures
- Zone 3
- Heal well, good prognosis, absence of tendon sheath
- May need to release A1 pulley
- Direct surgical repair
- Zone 4
- Direct repair
- Release carpal tunnel (do not have to repair, but if you do, add a z-lengthening to decrease pressure in carpal tunnel
- Assess for concommittant median nerve injury
- Zone 5
- Direct repair
- Good vascular supply, better progrnosis than zone 2 injuries
Which of the following has the best evidence to support its use in preventing surgical site infections?
a) Preoperative Chlorohexodine Bathing
b) Adhesive Draping
c) Vancomycin Powder
d) Proviodine-Iodine Irrigation
a) Preoperative Chlorohexodine Bathing
- Has good evidence but can have low patient compliance.
- Recommended to have patient reminders to increase compliance
- Adhesive Draping - little evidence, some suggests even increase in infection rates
- Proviodine Irrigation - May be effective but limited evidence. Little harm.
- Vanco powder - Decreases SSI in spine surgery, more studies needed.
- Incisional VAC - shown to decrease infection rates
- Detrimental effects in postop primary total knee arthroplasty (blisters)
- Silver Dressings - Decreased SSI in arthroplasty
- Good potential
- Expensive
In which phase of tendon healing do you get the greatest rate of increased strength of repair?
a) Inflammatory
b) Proliferative
c) Remodelling
d) Cosolidation
b) Proliferative- greatest rate of increased strength
- Inflammatory
- 48-72 hours
- Strength equal to repair
- Proliferative
- 5 days to 4 weeks
- Greatest proportional increase in strength
- Remodelling
- up to 2 years
- achieve full post repair strength
Which is not a branch of the posterior division of the internal illiac a.?
a) Obturator a.
b) Supeiror gluteal a.
c) Illiolumbar a.
d) Lateral Sacral a.
a) Obturator - branches from anterior interal illiac.
Internal Illiac A.
- Anterior
- Obturarot a.
- Inferior gluteal a.
- Umbilical a.
- Inverior vesicular a.
- Medial rectal a.
- Internal pudendal a.
- Uterine and vaginal a. (in women)
- Posterior
- Superior gluteal a.
- Iliolumbar a.
- Lateral sacral a.
All are true in wheel-chair bound patients except:
a) overall increased shoulder stregnth comared to regular population
b) reletive weakness in adduction is predictor of shoulder pain/patholgy
c) higher prevlanece of shoulder pain in these groups
d) non surgical management for shoulder pain is ineffective
d) non surgical management for shoulder pain is ineffective
Nonsurgical options have shown to be effective
- NSAIDS
- JOint inection
- Physio
- Activity modification (body shift vs lift transfers, temporary motoraized wheelchair)
Describe the Tile Classification of Pelvic Fractures.
- Type A - Stable
- Type B- Rotationally unstable, vertically stable
- Type C - rotationally and vertically unstable
In regards to glenohumeral OA in wheelchair bound patients, which of hte following is true?
a) Arthroplasty is contraindicated through a weightbaring shoulder
b) Hemiarthroplasty is considered for patients <65 years of age or with full thickness rotator cuff tear regardless of age.
c) Total shoulder arthroplasty considered for patients >65 years of age with concomittiant full thickness cuff tear
d) All patients in this population with arthirtis should recieve a rTSA.
b) Hemiarthroplasty is considered for patients <65 years of age or with full thickness rotator cuff tear regardless of age.
- Non reparative surgical options:
- Subacromial decompression
- acromioplasty
- distal clavicle resection
- RCR
- double row repair favoured due to increased loads/earlier rehab in wheelchair users (expert opinion)
- LHB: tenotomy vs. tenodesis controversial.
- Tenotomy allows quicker rehab, while tenodesis keeps humeral head depressed
- Glenohumeral OA:
- If patient >65 and RC intact proceed with TSA.
- If patient <65 OR if RC is deficient regardless of age, proceed with hemi.
- Avoid RTSA as cannot handle the forces of WB shoulder.
- Subacromial decompression
What is true regarding S.Aureus nasal colonization and SSIs?
a) Can be detected with PCR only.
b) Most common decolonization method is mucopirocin nasal ointment.
c) Mucopirocin is recommended for empiric treatment.
d) Sceening is not required for nasal S. Aureus colonization.
b) Most common decolonization method is mucopirocin nasal ointment.
- Screening protocols recommended.
- Mucopirocin not recommended for empiric treatment due to risk of resistence
- S. Aureus mos tcommon cause of SSI, carriers have higher risk of SSIs
- Can detect with PCR (faster) or traditional cultures (cheaper).