Recon Flashcards
What are the two major criteria from MSIS?
Sinus tract to prosthesis, or positive isolated pathogen on two separate cultures
An MSIS score greater than what indicates a prosthetic joint infection?
> /= 6
Catastrophic failure is most commonly seen in what total joint arthroplasty?
Total knee arthroplasty (less common in THA and TSA)
Sliding wear is most pronounced in what type of total knee design?
Cruciate retaining with flat PE insert
In TKA, a tight […] gap hastens sliding wear effect on the polyethylene insert
flexion
In TKA, a PE thickness of less than […] mm is associated with catastrophic PE failure
8
[…] alignment of knee associated with catastrophic PE failure
Varus
What is the most common form of polyethylene sterilization?
Gamma radiation
Cross-linked polyethylene improves resistance to what two types of wear?
Adhesive and abrasive wear
Oxidized polyethylene leads to early failure due to what three characteristics?
- Subsurface delamination
- Pitting
- Fatigue strength/cracking
What mechanical properties decrease with cross-linked polyethylene?
Ductility and fatigue resistance
What packing elements are used to obtain cross-linked polyethylene?
Argon and nitrogen
What is the most effective means of removing free radicals from polyethylene?
Thermal stabilization / remelting
What are the two methods used to removal free radicals from polyethylene?
Thermal stabilization (remelting) and annealing
What method changes the polyethylene from its partial crystalline state to its amorphous state?
Thermal stabilization / remelting
What is a disadvantage of thermal stabilization/remelting of polyethylene?
Reduces mechanic properties
What method of removal of free radicals from polyethylene maintains the mechanical properties of the polyethylene?
Annealing
Which method of free radical removal from polyethylene occurs above the polyethylene melting point?
Thermal stabilization / remelting
Which method of free radical removal from polyethylene occurs below the PE melting point?
Annealing
Which method of free radical removal from polyethylene is less effective and why?
Annealing; process occurs below the PE melting point
Which method of removal of free radicals from polyethylene leaves the PE more susceptible to oxidative stress and why?
Annealing; process occurs below the PE melting point
Irradiation of polyethylene in […] or […] minimizes oxidation
An inert gas or vacuum
Calcium steerage additive to polyethylene leads to […] defects in PE
Fusion
What is the best PE fabrication process?
Direct compression molding / net shape
Use of direct compression molding of PE results in less [… …] formation and propagation compared to ram bar extrusion
Fatigue crack
What is the incidence of PJI in a primary TKA?
1-2%
What is the incidence of PJI in a primary THA?
0.3-1.3%
What is the incidence of PJI in a revision TKA?
5-6%
What is the incidence of PJI in a revision THA?
3-4%
DMARDs should be stopped […] weeks prior to TJA
4-6 weeks
In TJA, systemic antibiotics should be administer within […] to incision, and greater than […] prior to tourniquet.
30 minutes; 10 minutes
[…] airflow systems can help prevent PJI
Vertical laminar
What organism is most commonly associated with acute THA PJIs?
S aureus
Acute PJI occurs within [..] weeks of surgery
3-6
Bioflim created by all bacteria forms on implant within […] weeks
4
Biofilm is composed of […] percent cells and […] percent glycocalyx
15%; 85%
In PJI, […] allows biofilm to adhere to prosthesis and seal off infection to protect bacteria from host immune system?
Glycocalyx
[…] refers to the concentration of bacteria needed in order to shift the colony’s focus away from replication and toward biofilm production
quorum
Prosthetic explanation is indicated with infection greater than […] weeks due to biofilm
4
What is the most common organism in chronic THA PJIs?
S epidermidis
On a bone scan, Tc-99m detects […]
Inflammation
On a bone scan, what substance is used to detect leukocytes?
In-111 (indium)
A CRP above 10 mg/L or D-dimer above 860 ng/mL is how many points on the MSIS criteria for PJI?
2 points
On the MSIS criteria, an elevated ESR is how many points?
1 point
A synovial WBC above […] is 3 points on the MSIS criteria
3,000 cells
What is the most sensitive and specific marker forPJI?
Αlpha defensin
Elevated synovial PMNs above […] percent is 2 points on the MSIS PJI criteria
80%
An elevated synovial CRP above […] is 1 point on the MSIS PJI criteria
1 point
CRP peaks […] days after surgery and returns to normal at […] days
2-3 days; 21 days
An ESR peaks […] days after surgery and returns to normal at […] days
5-7 days; 90 days
WBC greater than […] and PMN percentage greater than […] on synovial aspiration of a MoM hip is suggestive of infection
WBC above 4350 and PMN above 85%
When assessing for PJI, one should wait […] weeks for repeat aspiration after completing antibiotics
2 weeks
Αlpha- defensin is a peptide released by […]
Neutrophils
A DAIR procedure can be indicated if the initial TJA was completed […] weeks prior
3-4
A DAIR procedure can be indicated if the onset of symptoms to treatment is within […] hours
48-72 hours
When performing a two-stage replacement arthroplasty for PJI, delayed reimplantation greater than […] weeks has a 70-90 percent success rate
6
The use of static antibiotic spacers in PJIs are indicated with:
- flap coverage
- ligamentous instability
- extensive bone loss
Compared to static antibiotic spacers, articulating spacers have […] functional outcomes and […] rate of infection recurrence
equivalent; equivalent
For antibiotic spacers, each 40 g bag of cement should have […] g of vancomycin and […] g of tobramycin added
3 grams of vanco; 4 grams of cobra
Antibiotic spacer elution is dependent on what three characteristics?
- antibiotic concentration
- surface area (beads increase area)
- cement porosity
When making an antibiotic spacer, adding vancomycin powder after cement powder + liquid monomer mixed for […] results in greater elution
30 seconds
In PJI, there is a poorer prognosis for two-stage revision for […] organisms
methicillin-resistant
Is there a higher rate of hip OA amongst males or females?
Females
In hip OA, articular cartilage water content is […]
increased
In hip osteoarthritis, what enzymes are responsible for cartilage matrix digestion?
matrix metalloproteases (MMPs)
What is stromelysin?
matrix metalloprotease; responsible for cartilage matrix digestion in hip OA
What inflammatory cytokines are secreted by synoviocytes and increase MMP synthesis?
IL-1, IL-6, TNF-a
What is the genetic inheritance pattern of hip OA?
non-mendelian
On the histology of hip OA, there is cartilage destruction with […] of subchondral bone
eburnation
A walking stick decreases the hip joint reaction forces on the affected hip when placed in the […] upper extremity
contralateral
Hip arthroscopy is not recommended for Tönnis grade […] radiographic arthrosis due to high rate of conversion to hip arthroplasty
2
According to the most recent literature, WBC greater than […] and PMN percentage greater than […] should be considered suggestive of infection in a TKA.
1100 cells/mm3 and 64 percent PMNs
The process of irradiation of polyethylene causes […] which leads to cross-linking and increased […] resistance
free radical formation; wear
A surgical site infection (SSI) with an implant in place is defined as an infection related to the surgery that occurs within […] of the index procedure.
one year
According to the AAOS Guidelines for the diagnosis of hip and knee periprosthetic joint infections (PJI), there is a […] recommendation for performing a joint aspiration in patients with an abnormal ESR and/or CRP.
STRONG
A BMI great than […] increases risk of postoperative joint infection.
40
An albumin less than […] indicates malnutrition and increases risk of postoperative joint infection
<3.5 g/dL
Retention of a Foley catheter for long than […] increased the risk of postoperative joint infection
1 day
The gene that confers methicillin resistance in MRSA is […]
mecA
Compared to a cruciate retaining knee prosthesis, an anterior stabilized prosthesis has what effect on the contact area and what effect on the stability in PCL deficient knees?
increased contact area (due to increased conformity) and increased stability
In hip osteonecrosis, bilateral hips are involved […] percent of the time
80
In idiopathic avascular necrosis of the hip […] is the final common idiopathic pathway
intravascular coagulation
AVN due to trauma is due to injury to the […]
femoral head blood supply
If reduced within 6 hours, the rate of AVN in a traumatic hip dislocation is […] percent
2-10
Presence of […] on MRI is predicitve of worsening pain and future progression of hip AVN
bone marrow edema
Bisphosphonates are indicated in the treatment during what stage of hip AVN?
indicated for precollapse AVN (Ficat stages 0-II)
Vascularized free-fibula graft for the treatment of hip AVN is less predictable in patients greater than […] years old
40
THA in young patients with osteonecrosis, there is a higher rate of […] wear of the polyethylene liner and a higher rate of […] than compared to older patients who have THA for osteoarthritis
linear; osteolysis
Risk of femoral head collapse with osteonecrosis is based on the […] angle
modified Kerboul combined necrotic
A combined necrotic angle of less than […] degrees on the modified Kerboul combined necrotic is classified as low risk of femoral head collapse
190
A combined necrotic angle between […] degrees on the modified Kerboul combined necrotic is classified as moderate risk of femoral head collapse
190-240
A combined necrotic angle of greater than […] degrees on the modified Kerboul combined necrotic is classified as high risk of femoral head collapse
240 degrees
What is an absolute contraindication to hip resurfacing?
Poor femoral head or neck bone stock (eg cystic changes in head)
Coxa […] is a relative contraindication to hip resurfacing due to increased risk for FNF
vara
Compared to THA, the stability of hip resurfacing is better, equivocal, or worse?
better
Compared to THA, hip resurfacing have […] restoration of hip biomechanics with […] risk of limb length discrepancy
improved; lower
Hip resurfacing has better outcomes when used in young, larger males with excellent bone stock treated for […]
osteoarthritis than for dysplasia or osteonecrosis
What is the most common early (within 3 years) complication of hip resurfacing?
Femoral neck fracture
What is the most common cause for revision in acute post-operative period (20 weeks) following a hip resurfacing?
femoral neck fracture
The incidence of heterotypic ossification in hip resurfacing is […] than a THA.
higher; due to larger exposeure
Most cases of metallosis in hip resurfacing is related to […] of the implant
edge loading
The dislocation risk of hip resurfacing is […] than convention THA
lower
Dual mobility liners have a unique risk of liner […] in the acetabular cup.
malseating
In press-fit femoral stem, […] provide initial stability
compression hoop stresses
In the setting of THA, intra-operative fractures are more likely to occur when using which femoral stem type and through which approach?
press-fit through a lateral approach
Titanium is […] stiff than cobalt-chrome or stainless steel stems
less
Cemented titanium stems leads to […] corrosion
crevice
MoM debris particles are […] than those of MoP
smaller (but more numerous)
In metal-on-metal-related delayed type hypersensitivity, the EFFECTOR cell is […], while the most common/participating cell is the […].
T-cell; Macrophage
What hypersensitivity reaction is seen with MoM hips?
Type IV - delayed type hypersensitivity
Delayed Type IV hypersensitivity is mediated by what cell?
T - cell
What is the most participatory cell in the delayed Type IV hypersensitivity reaction?
Macrophages (have been activated by T - cells)
In THA, what bearing surface has the best wear properties of all bearing surfaces?
ceramic on ceramic
[…] a crescent shaped line on a ceramic femoral head caused by contact between the femoral head and rim of the cup during partial subluxation
Stripe wear
Which bearing surface in THA is standard of care?
ceramic on polyethylene
MoM pseudotumor is also known as?
aseptic lymphocyte-dominant vasculitis-associated lesion
What is the incidence of pseudo tumor in MoM THA?
10-15%
A high acetabulum inclination angle greater than […] degrees is a risk factor for developing MoM pseudotumor.
55 degrees
What is the predominant cell type in MoM pseudotumor?
lymphocytes
In MoM hips, serum metal ion concentration highest at […] months following index surgery
12-24
In MoM hips, serum values great than […] is generally an indication for advanced imaging with MRI
7 parts per billion (ppb, or ug/L)
In THA revisions, […] transfer can be used to reconstruct deficient abductor mechanism
gluteus maximus
14-20 percent of revision THAs performed due to a MoM pseudotumor require a 2nd operation within […] years
5
What is the most likely cause of a pseudotumor in a well-positioned total hip arthroplasty?
Fretting and corrosion reaction from the taper
[…] approach to the hip has decreased dislocation rate when compared to posterior approach in numerous studies
direct anterior (Smith-Peterson)
With a direct anterior approach to the hip there is no difference in gait biomechanics at […] months compared to other approaches
3
When performing a direct anterior approach, the […] retractor can result in femoral nerve injury
anterior
In the approach for a THA, intraoperative fracture rate thought to be higher with what approach?
direct anterior (Smith-Peterson)
Which THA approach violates the abductor muscles and results in a post-operative limp?
Anterolateral approach and direct lateral approach
What is the inter-muscular interval for an anterolateral (Watson-Jones) approach to the hip?
tensor fascia lata and gluteus medius
Which approach for a THA utilizes the interval between tensor fascia lata and gluteus medius?
Anterolateral approach (Watson-Jones)
Which approach for a THA splits gluteus medius and vastus lateralis?
Direct lateral approach (Hardinge)
Which approach for a THA has a higher rate of heterotopic ossification?
Direct lateral approach (Hardinge)
In the setting of THA, an extended trochanteric osteotomy requires which type of stem?
Diaphyseal engaging
In THA, adding a skirt […] the head-neck ratio
decreases
[…] head-neck ratios allow greater arc range of motion prior to impingement
Larger (ie a larger femoral head)
In THA, what is the definition of jump distance?
amount of translation prior to dislocation
In THA, increasing neck shaft angle (more valgus) compared to native anatomy can […] leg length and […] offset
increase; decrease
In THA, decreasing neck-shaft angle (more varus) compared to native anatomy can […] leg length and […] offset
decrease; increase
Medialization of the acetabular cup […] the moment arm of the abductors and […] the joint reactive force.
increases; decreases
The recommendations are femoral component anteversion of […] degrees
10-15
The recommendations are acetabulum anteversion of […] degrees
5-25
The recommendations are acetabulum abduction of […] degrees
30-50
In a THA, the recommended combined version is what?
37 degrees of anteversion
What is the definition of offset in regards to THA?
the perpendicular distance from the center of rotation of the femoral head to the axis of the femur
In THA, increased offset leads to […] impingement
decreased
In THA, increased offset leads to […] joint reactive forces
decreased
In THA, decreasing neck-shaft angle leads to […] offset
increased
Underreaming by […] can increased the risk for intraoperative acetabulum fractures.
2 mm
If an intraoperative acetabulum fracture occurs and the posterior column is compromised, […] is most stable construct
ORIF + revision
What is the treatment for intra-operative periprosthetic longitudinal calcar split?
stem removal, cables, reinsertion (can ignore if fully coated porous stem was used)
In the setting of intra-operative periprosthetic femur fracture, what is the treatment for a cortical diaphyseal perforation?
Fully porous coated stem(bypass by 2 cortical diameters)
In the setting of THA, cementless prosthesis tend to fracture in the first […] months
6
Early postoperative periprosthetic femur fractures are likely caused by stress risers during […] and […]
reaming and broaching
In early postoperative periprosthetic femur fractures, […] stems cause proximal fractures
wedge-fit tapered designed
In early postoperative periprosthetic femur fractures, […] stems tend to cause a distal split in the femoral shaft
cylindrical fully porous-coated
Cementless femoral prostheses tend to fracture […] in the post operative period; whereas cemented femoral prostheses tend to fracture […]
early (first 6 months); late (5 years out)
Vancouver A2 fractures with less than […] of displacement can be treated non-operatively with partial weight bearing
2 cm
70 percent of prosthetic hip dislocations occur within […] post-operatively
first month
What is the greatest risk factor for prosthetic hip dislocation?
prior hip surgery
A BMI less than […] or a BMI greater than […] increases the risk for a prosthetic hip dislocation
20; 35
Which bearings surfaces increase the risk for prosthetic hip dislocation?
Metal on poly, or metal on metal
Do cemented or uncemented hip components have an increased risk for prosthetic hip dislocation?
cemented
In a posterior approach to the hip, what can decrease the risk of a prosthetic hip dislocation?
repair of the capsule and external rotators
Ideal positioning of acetabular component is […] degrees of abduction and […] degrees anteversion
40; 15
Utilization of a lateralized acetabular liner increases […]
femoral offset
Utilization of a lateral acetabular liner […] femoral offset
increases
What is the most common cause for medical malpractice litigation following THA?
Sciatic nerve palsy
The sciatic nerve is closest to the acetabulum at the level of the […]
ischium
Which gender is at greater risk for sciatic motor nerve palsy with a THA?
Female
What four patient factors increase the risk for a sciatic motor nerve palsy?
female gender, DDH, pre-existing lumbar stenosis, post-traumatic arthritis
What five surgical factors increase the risk for a sciatic motor nerve palsy?
revision surgery, limb lengthening, surgeon self-rated procedure as difficult, operative time, cementless femoral fixation
In a THA sciatic nerve palsy, […] percent recover full strength after complete palsy
35-40
What type of corrosion is caused by an electrochemical transfer of electrons between dissimilar metals?
Galvanic
What type of corrosion is due to relative micromotion between two materials causing wear?
Fretting
[…] corrosion is a physicochemical interaction between a metal and environment leading to altered mechanical properties
Crevice
Which metal is most prone to crevice corrosion?
stainless steel
In trunnionosis, which metal ion is more elevated?
Cobalt is more elevated than chromium
A ratio of at least […] encountered when caused by head-neck junction trunnionosis, whereas a ratio of […] is suggestive of metal-on-metal implant wear
2:1; 1:1
In THA, volumetric wear is directly proportional to the […] of the femoral head
radius squared
Type I Paprosky
Minimal deformity, intact rim
What is the definition of Type IIA Paprosky?
Superior medial bone lysis with intact superior rim
What is the definition of Type IIB Paprosky?
Absent superior rim, superolateral migration
What is the definition of Type IIC Paprosky?
Localized destruction of medial wall
What is the definition of Type IIIA Paprosky?
Bone loss from 10am-2pm around rim, superolateral cup migration
What is the definition of Type IIIB Paprosky?
Bone loss from 9am-5pm around rim, superomedial cup migration
In the setting of THA, thigh pain is suggestive of a problem with […]
the femoral component
In the setting of THA, get up and go pain is pathognomonic for […]
component loosening
In the setting of THA, night pain is suggestive of […]
infection
Femoral stems most commonly subside in […]-version
retroversion
What imaging study can be helpful to determine relationship to neurovascular structures with Paprosky IIIB defects?
angiogram
What is the most common complication after impaction bone grafting in a revision THA?
stem subsidence
In revision acetabulum, in order to use a porous-coated hemisphere cup or jumbo secured with screws, at least […] percent of bone stock needs to be present to support cup
50
In revision hip arthroplasty, a reconstruction cage with structural bone allograft is indicated when less than […] of the rim remains or less than […] percent of bone stock is present.
2/3; 50
In revision THA, when there is pelvic discontinuity, what is the acetabulum component used for treatment?
custom triflange cup
What is the most common complication following isolated hip liner exchange?
hip instability
Osteolysis represents a […] response to wear debris
histiocytic
In volumetric wear in THA, […] is the most important factor in predicting particles generated
head size
In THA, polyethylene linear wear rates greater than […] have been associated with osteolysis and subsequent component loosening
0.1 mm/year
Highly cross-linked UHMWPE generates […] wear particles and is […] resistant to wear
smaller; more
Highly cross-linked UHMWPE has […] mechanical properties compared to conventional non-highly cross-linked UHMWPE
reduced
Polyethylene thickness of less than […] increases the wear in THA
6 mm
Patients younger than […] increase the risk for PE wear in THA
50
Wear rates of PE in THA is increased in what gender?
Men
Femoral head size between […] mm in diameter does not influence wear rates of UHMWPE
22-46
[…] bearings have the lowest wear rates of any bearing combination
ceramic
metal-on-metal produces […] wear particles and […] wear rates compared to metal-on-polyethylene bearings
smaller; lower
Notch sensitivity is seen on what bearing surface in THA?
titanium
Metal-on-metal serum ion levels are greater with cup abduction angle greater than […] degrees and […] component size
55; smaller
[…] urine level is a marker for bone turnover and is elevated in osteolysis
N-telopeptide
N-telopeptide urine level is a marker for […] and is elevated in osteolysis
bone turnover
Which muscles can be transferred in an abductor deficiency?
anterior gluteus maximus; TFL
Which patient population(s) have increased failure rates with cemented TKA?
obese/morbidly obese, and young active males
Patch porous coating press fit TKA have been associated with an increased incidence of […]
metaphyseal osteolysis
The primary mechanism of wear in polyethylene acetabular components is […] and […].
adhesion; abrasion
The major modes of polyethylene wear in knees are […] and […]
delamination; fatigue cracking
In periprosthetic acetabulum fractures, pelvic discontinuity (eg Praposky Type IIIB) should be treated with what acetabular construct?
cup-cage construct
Femoral revision with a […] stem is the preferred method in the treatment of Paprosky type-IIIB femoral defects (<4 cm of diaphyseal bone available for distal fixation)
modular fluted tapered
In the setting of pelvic discontinuity with severe acetabular bone loss, revision to a […] would be the treatment choice
custom triflange cup
Paprosky […] is defined as pelvic discontinuity with severe acetabular bone loss and superomedial cup migration.
3B
The presence of a pseudotumor is associated with increased […] wear of both the acetabulum and the femoral components.
linear
The articular cartilage in knee osteoarthritis has […] water content and […] proteoglycans
increased; decreased
Osteophyte formation in knee osteoarthritis is mediated by what signaling molecule?
Indian Hedgehog
knee osteophytes form through the pathologic activation of […] ossification
endochondral
What is aggrecanase-1 (ADAMTS-4)?
matrix metalloproteases (MMPs)/proteolytic enzyme
An imbalance between MMPs and […] has been demonstrated in OA tissues
Tissue-inhibitors of MMPs (TIMPs)
In knee OA, there is often an increased […] moment to the limb during gait
adductor
Weight loss programs are recommended for patients with symptomatic knee OA and a BMI greater than […]
25
In younger patients with medial unicompartmental OA, a […]-producing HTO can be performed.
valgus
cruciate retaining vs. crucitate sacrificing implants show […] difference in outcomes
no
Compared to a TKA, UKA have […] blood loss
less
Compared to a TKA, UKA have […] recovery
quicker
Compared to a TKA, UKA have […] rates of PJI or wound complication
lower
Compared to a TKA, UKA […] post-operative pain leading to[…] hospital stays
less; shorter
A fixed varus deformity greater than […] degrees is a contraindication to UKA.
10
A fixed valgus deformity greater than […] degrees is a contraindication for UKA
5
Restricted ROM with a ROM arc of less than […] degrees is a contraindication to UKA.
90
A flexion contracture greater than […] degrees is a contraindication to UKA.
5-10 degrees
Inflammatory arthritis is a contraindication to what knee arthroplasty procedure?
UKA
What is the most common cause of early failure (5 years) of a UKA?
Aseptic loosening
What percentage of patients experience aseptic loosening of a UKA within five years?
25-45 percent
What two patient factors increase the risk of a tibial stress fracture in a UKA?
Patient activity and weight
Is the 10-year survivorship of UKA higher with fixed- or mobile-bearing?
higher in mobile bearing
In mobile-bearing UKA clinical results with 15-year survivorship reported at […] percent
93
Lateral UKA compartment arthroplasties have […] results to medial
equivalent
Revision rates of UKA are[…] than total knee revision rates
worse
What is the definition of femoral rollback?
the posterior translation the femur with progressive flexion
What ligaments control femoral follback in the native knee?
ACL and PCL
In a CR TKA, what ligament promotes femoral rollback?
PCL
What paradoxical motion is observed in a CR TKA?
anterior translation of femur in first 40 degrees of flexion
In a PS TKA, what promotes femoral rollback?
tibial post engaging with femoral cam
What is the disadvantage of modular TKA?
increased osteolysis and backside polyethylene wear
There is […] rates of osteolysis in modular TKA components compared to non-modular components.
increased
[…] cement has longer working time
high viscosity
Cementless TKA have […] operative times and […] cost of implants compared to cemented TKA
decreased; increased
Who is the ideal candidate for cementless TKA?
younger, active, and obese patients with good bone quality
What patient’s are contra-indicated from a cementless TKA?
eldery with osteoporotic bone; irritated bone; inflammatory arthritis
A cruciate-retaining TKA depends on an intact PCL to provide stability in […]
flexion
In order to use a CR TKA, the valgus deformity must be less than […] degrees and varus deformity less than […] degrees
15; 10
In a CR-TKA, a tight PCL may cause accelerated […] wear
polyethylene
In a CR-TKA, a loose or ruptured PCL may lead to […] and […]
flexion instability; subluxation
Resection of the PCL increases the […] gap in relationship to the […] gap
flexion; extension
What type of TKA design should be considered in a prior patellectomy?
PS TKA
In a PS-TKA, a cam-jump can occur with a loose […] gap
flexion
Patients with hyperextension instability need what type of knee design prosthesis?
Hinged TKA
In a mobile-bearing TKA design, bearing spin out can occur with a loose […] gap
flexion
All-polyethylene base plate TKA have […] costs and […] rates of osteolysis
decreased; decreased
In comparing all-polyethylene base plates with metal tray, studies show […] functional outcomes with […] cost
equivalent; decreased
UKA are contraindicated in obese patients weighing greater than […] kg.
82
Osteoarthritis and formation of osteophytes are felt to be mediated by the differentiation of quiescent […] through the Indian hedgehog signaling pathway.
chondrocytes
In osteoarthritis, there is […] permeability of water into cartilage
increased
In TKA, correction of […] and […] contracture deformity has highest risk of peroneal nerve palsy
valgus and flexion
In the setting of TKA, coronal plane deformities great than […] degrees cannot be corrected by intra-articular bone cuts and soft-tissue balancing alone and require an extra-articular osteotomy
20
The most important variable in proper patellar tracking is preservation of a normal […].
Q angle
What are the absolute indications for patella resurfacing?
- inflammatory arthritis
- patella maltracking
- PF arthritis is main indication for TKA
There is [..] anterior knee pain with patella resurfacing
less
There is […] revision rates with patella resurfacing
less
There is […] revision rates with patella resurfacing
less
[…] and[…] given immediately before TKA reduce postoperative pain
NSAIDs and opioids
Is regional or general anesthesia preferred for post-op pain management in TKA?
regional (spinal/epidural)
Selective COX-2 inhibitors inhibit the transformation of […] to […]
arachidonic acid to prostaglandins
What is the MOA of gabapentin/pregabalin?
reduce hyper-excitability of voltage dependent Ca2+ channels in activated neurons
What degree of knee flexion is needed for the swing phase of gait?
65
What degree of knee flexion is needed for ADLs?
90
What degree of knee flexion is needed for stairs?
95
What degree of knee flexion is needed to rise from a chair?
105
In the setting of TKA stiffness, treatment is manipulation under anesthesia for flexion under […] degrees within first […] weeks of surgery.
90; 12
In the setting of TKA stiffness, treatment of arthroscopic lysis of adhesions is indicated for flexion less than […] degrees after […] weeks.
90; 12
What is the most important risk factor for post op TKA stiffness?
poor preoperative ROM
Age younger than […] years is a risk factor for post of TKA stiffness.
55
In a valgus knee, an isolated release of the popliteus may be utilized to preferentially increase the […] gap.
lateral flexion space
In a valgus TKA, when the knee is found to be tight in flexion, release of the […] may be performed to increase the lateral flexion gap preferentially.
popliteus tendon
Recessing or releasing the PCL will increased the […] gap
flexion
The posterior condylar axis is normally […] rotated to the transepicondylar axis.
3 degrees internally
Moving the femoral component anterior […] the flexion gap.
increases
What is the most common intraoperative fracture in a TKA?
Medial femoral condyle
What is a Su Type I femur fracture?
Fracture is proximal to the femoral component
What is a Su Type II femur fracture?
Fracture at proximal extent of femoral component and extends proximally
What is a Su Type III femur fracture?
Any part of the fracture line is distal to the upper edge of anterior flange of the femoral component
In retrograde IMN of a TKA, femoral component may cause starting point to be more […] than normal and lead to […] at the fracture site
posterior; hyperextension
In treating a periprosthetic distal femur fracture, a condylar buttress plate (non locked) does not resist […] collapse
varus
In periprosthetic distal femur fractures, there is an increased risk of […] in plating via extensile lateral approach compared with submuscular approach
nonunion
In plating periprosthetic distal femur fractures, there is an increased risk of […] with minimally-invasive approach/MIPO
malunion
Compared to ORIF, a DFR has […] in major complications and […] reoperation rate
no difference; no difference
What is the most common reason for revision TKA?
infection
What is the most common cause for early revision TKA?
infection
What is the most common cause for late revision TKA?
aseptic loosening
What is the SECOND most common cause for revision TKA?
Aseptic loosening
Which component is more commonly loose in aseptic loosening of a TKA?
tibial
Is osteolytic wear more common in cemented or uncemeted TKA?
uncemented
PCL attenuation in CR TKA can lead to what type of instability?
Flexion instability
A femoral component placed in […] can lead to flexion instability in a TKA.
hyper-extension
In the setting of TKA, tibial joint line should be […] cm above head of fibula
1.5 to 2
In a revision TKA, a cavitary lesion less than […] can be filled with cement.
1 cm
In a revision TKA, a metaphysical sleeve is not useful for […] defects
uncontained
In revision TKA, trabecular metal cones can be used for […] defects
uncontained
In the setting of revision TKA, unconfined defects should be treated with which type of implant?
trabecular metal cones
In the setting of revision TKA wiht multiple prior scars/incision, the most […] incision should be used.
lateral
In the setting of revision TKA, incisional negative pressure wound therapy associated with […] rate of wound complications
improved
The use of adductor canal blocks results in […] postoperative ambulation compared to femoral nerve blocks
earlier
