Joints Flashcards

1
Q

Rheumatoid arthritis is…

A

a T-cell mediated autoimmune disease.

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2
Q

Rheumatoid factor is…

A

an IgM autoantibody that targets IgG.

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3
Q

TNF alpha inhibitors

A
  • Infliximab
  • Etanercept
  • Adalimumab
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4
Q

Surgical management of TNF alpha inhibitors

A

Hold 1 week prior to surgery and 2 weeks after

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5
Q

Rituximab

A

CD20 inhibitor (B cells)

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6
Q

Abatacept

A

fusion protein that inhibits T cells

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7
Q

Juvenile idiopathic arthritis

A
  • less than 16 years old
  • elevated ESR/ANA
  • need opthamologic eval (slit lamp exam)
  • can have atlantoaxial instability (like RA)
  • treat with DMARDs (like RA)
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8
Q

Reiter’s syndrome

A

-arthritis, urethritis, conjunctivitis/uveitis

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9
Q

Which meds can be continued during surgery?

A

methotrexate, leflunomide, hydroxychloroquine

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10
Q

Timing of surgery with regards to rituximab

A

surgery 7 months after last dose

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11
Q

Volumetric wear

A

pi x r ^2 x w (where w is linear wear)

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12
Q

Polyethylene is best made by…

A

direct compression molding of powder

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13
Q

Crosslinking PE improves…

A

wear resistance (especially adhesive wear) but reduces mechanical properties (fracture toughness, tensile strength).

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14
Q

Sterilization of PE is done by…

A

irradiation in inert gas. Irradiation generates free radicalas which facilitate cross linking of PE and improve wear.

However, too many free radicals (irradiation in the presence of air) is bad bc they cause oxidative degradation of PE.

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15
Q

How to remove excess free radicals after irrradiation

A

remelting (heat PE past melting point) and annealing (heat PE close to melting point)

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16
Q

Effect of remelting and annealing on crystal formation of UHMWPE

A
  • annealing increases

- remelting decrease

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17
Q

Which bearing surface provides the least volumetric wear?

A

ceramic on ceramic

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18
Q

Stripe wear

A

characteristic pattern of ceramic on ceramic bearings from lift off separation of femoral head coming into contact with the acetabular rim

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19
Q

Risk factors for stripe wear and thus liner fx

A

vertical cup

obesity

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20
Q

metal on metal hips produce

A

smaller wear particles than metal on PE

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21
Q

Pseudotumor is also known as…

A

aseptic, lymphocyte dominated vasculitis-associated lesion (ALVAL)

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22
Q

Urinary N telopeptide is…

A

a marker for osteolysis and a breakdown product of type I collagen.

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23
Q

Best predictor of pain w/ AVN is…

A

bone marrow edema on MRI.

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24
Q

What Kerboul angle poses a high risk for femoral head collapse?

A

> 240

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25
Q

In sickle cell, the natural history of AVN is..

A

progressive loss of sphericity of the femoral head

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26
Q

Hip OA cartilage characteristics

A

increased water content

decrease proteoglycan content

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27
Q

In hip OA, IL-1, IL-6 and TNF-alpha increase…

A

MMP activity leading to cartilage degeneration.

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28
Q

In OA, indian hedgehog (Ihh) mediates..

A

activation of chondrocyte differentiation –> osteophyte formation (pathologic activation of endochondral ossification).

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29
Q

Bleeding under the transverse acetabular ligament is from…

A

the obturator artery.

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30
Q

What is most effective at reducing EBL during THA?

A

spinal anesthesia (and therefore transfusion requirement)

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31
Q

Pseudotumor is generally caused by…

A

fretting and corrosion reaction from taper.

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32
Q

After THA, safe to return to driving after…

A

2 weeks.

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33
Q

Medializing the acetabular component will…

A

decrease joint reactive forces.

34
Q

Increasing femoral offset will..

A

decrease joint reactive forces.

35
Q

Intra-operative femoral fx is highest when placing…

A

uncemented femoral stem via the lateral approach.

36
Q

Sickle cell anemia has risk of perforation of femoral canal during THA bc of…

A

sclerosis.

37
Q

Posterosuperior quadrant

A
  • *safe zone

- dangers include sciatic nerve, SGN and vessels

38
Q

Posteroinferior quadrant dangers

A

sciatic nerve, IGN and vessels

39
Q

Anteroinferior quadrant dangers

A

obturator nerve/vessels

40
Q

Anterosuperior quadrant dangers

A

external iliac vessels

**death zone

41
Q

Cement fixation ideal mantle

A

> 2 mm

42
Q

Biologic fixation (rule of 50s)

A
  • pore size 50-150 micrometers
  • porosity 50%
  • gap < 50 micrometers
  • micromotion < 150 micromotion
43
Q

Sciatic nerve palsy is usually the…

A

peroneal division.

44
Q

Treatment of sciatic nerve palsy

A
  • AFO for persistent foot drop

- if fails nonop, posterior tibialis tendon transfer

45
Q

Interval of the anterolateral (watson jones) approach

A

TFL (SGN) and GMed (SGN)

46
Q

Interval of the direct lateral (Hardinge) approach

A

transgluteal

47
Q

Risk of direct lateral approach

A
  • SGN injury (located 4-5 cm about tip of GT)
  • abductor injury (trendelenberg gait)
  • HO

(**but lower dislocation)

48
Q

For knee OA, AAOS recommends…

A

NSAIDs, Tramadol, and PT to start on day of surgery.

49
Q

What is the most effective nonsurgical treatment for knee OA?

A

weight loss

50
Q

For knee OA, AAOS recommends against…

A

hyaluronic acid injection.

51
Q

Gait associated with knee arthritis

A

increased knee adductor moment

52
Q

As the knee flexes, the center of pivot is…

A

medial (femoral condyle rolls back around center of the medial compartments) and the tibia internally rotates (while the femur externally rotates)

53
Q

Outcome of medial parapatellar approach compared to quadriceps-sparing approach

A

better alignment of components

54
Q

2 times to use posterior stabilized implant

A
  • inflammatory arthritis

- previous patellectomy

55
Q

Treatment of arthrofibrosis after TKA

A
  • MUA before 3 months if knee flexion < 90 degrees

- after 3 months, surgical lysis of adhesions

56
Q

Adverse effect of metal tibial baseplate with PE insert

A

more backside PE wear

57
Q

If MCL is inadvertently cut during TKA, treat with…

A

primary repair of MCL w/ sutures or suture anchors and brace post-op.

58
Q

Most common intraoperative fx for TKA is…

A

medial femoral condyle.

59
Q

Best method for reduction of infection is…

A

weight loss (BMI < 40).

60
Q

Cutting the PCL will…

A

increase the flexion gap more than the extension gap.

61
Q

What amount of coronal and sagittal deformity can be corrected through intra-articular bone cuts during TKA?

A

20 degrees

62
Q

History of HTO in TKA can lead to…

A

patella baja

63
Q

How to address patella baja in TKA

A

place patella component superiorly and lower the joint line (cut less femur, cut more tibia)

64
Q

Compared to a TKA, UKA has…

A

better knee biomechanics and earlier rehab.

65
Q

Contraindications for UKA

A
  • inflammtory arthritis
  • ACL deficiency
  • fixed sagittal or coronal deformity
  • multiple compartment arthritis
66
Q

Patellar clunk syndrome

A

in a PS knee, scar tissue gets caught in the cam as the knee is flexed, then it gets displaced as the knee is extended causing a clunking sensation

67
Q

Risk factors for patellar clunk syndrome

A

small patellar component
over-resection of the patella
low placement of the patellar component

68
Q

How to treat a tibial metaphyseal defect

A

tantalum trabecular metal cone

69
Q

Macrophags release….

A

local factors TNFalpha –> activation of osteoclasts and bone resorption

70
Q

In acetabular dysplasia, what percentage of acetabular cup may be uncovered without risk for aseptic loosening?

A

30-40%

71
Q

An offset liner can lead to…

A

early acetabular component loosening.

72
Q

How to treat acetabular revision

A

adequate bone stock: porous coated hemispheric cup

inadequate bone stock w/ pelvic discontinuity: custom triflange is best

73
Q

Paprosky acetabluar bone loss type III is associated with…

A

superior cup migration.

IIIA: superolateral cup migration
IIIB: superomedial cup migration.

74
Q

Femoral metaphyseal bone deficiency you need at least…

A

4 cm of good femoral diaphyseal bone to obtain good scratch fit along the isthmus during revision THA (Paprosky IIIA femoral defect).

75
Q

If you have a stable acetabular fx, treat with…

A

protected weight bearing.

76
Q

For periprosthetic distal femur fractures, compared to IMN, locked plating has…

A

a higher nonunion rate.

77
Q

Comparison of submuscular vs extensile lateral approach for plating of periprosthetic distal femur fractures

A

submuscular plating has lower nonunion rate

diabetes is risk factor for failure

78
Q

Dental ppx rules for total joints

A

ppx w/ amoxicillin or cephalexin given 1 hour before dental procedure for 1st 2 years post-op

79
Q

Definition of SSI

A
  • if surgery involves retaining hardware, SSI is within 365 days
  • if no hardware is retained, within 30 days
80
Q

Alpha defensin is…

A

an antimicrobial peptide secreted by neutrophils

81
Q

Acute PJI

A
  • within 4 weeks

- aspirate within 6 weeks with synovial WBC 27,800 has 95% predictive value of PJI

82
Q

Chronic PJI

A
  • after 4 weeks
  • aspirate:
    • TKR WBC > 1100 w/ PMN > 64%
    • THR WBC > 3000 w/ PMN > 80%