Sm Caq - Knee: Art Cart/oa/ocd/synovial Dz

Front 1

% acute traumatic knee arthrosis w full-thickness chondral injury?

Back 1

5-10%

Front 2

Zones of articular cartilage organization?

Back 2

1) Superficial
2) Middle (transitional)
3) Deep (radial)
4) calcified cartilage

Front 3

Superficial zone cartilage?

Back 3

-forms gliding surface
-thin collagen fibrils parallel to surface
-Elongated chondrocytes parallel to surface
-Proteoglycan content=lowest
-Water content=highest(~80%)

Front 4

Middle/Transitional zone articular cartilage?

Back 4

-larger diamete collagen fibrils
-less apparent organization
-chondrocytes rounded in appearance

Front 5

Deep Zone articular cartilage?

Back 5

-Proteoglycan content=highest
-water content=lowest
-larger diameter collagen fibers organized perpendicular to joint surface

Front 6

Zone of Calcified (articular) Cartilage?

Back 6

-Separated from Deep Zone by Tidemark
-Separates hyaline cartilage from subchondral bone
-Small round chondrocytes in matrix

Front 7

"Tide Mark"?

Back 7

-Wavy blue line on H&E
-separarates deep zone from calcified cartilage

Front 8

Fluid phase caritlage?

Back 8

Water and electrolytes

Front 9

Solid phase cartilage?

Back 9

collagen, proteoglycans, and other proteins

Front 10

type II collagen?

Back 10

-90-95% of hyaline cart collagens
-distributed throughout matrix
-quarter-staggered array

Front 11

Type VI Collagen?

Back 11

-localized to pericellular capsule of chondrons
-may be important in tethering chondrocyt to pericellular matrix

Front 12

Type IX Collagen?

Back 12

-Interruptions in triple helical domains
-does not form fibrillar structures on its own
-Stabilizes collagen network by linking Type II collagen fibrils

Front 13

Type X Collagen?

Back 13

-Appears to exist extracellularly in form of fine fibrous mats
-localized to deep calcified zones of mature joints
-may play role in mineralization process above subchondral bone

Front 14

Type XI Collagen?

Back 14

-Forms thinner fibrils
-links to itself as part of network

Front 15

Major types of proteoglycans in articular cartilage?

Back 15

Chondroitin Sulfate (55-90%)
Keratan Sulfate (25-50%)
Dermatan Sulfate

Front 16

General characteristics of Proteoglycans?

Back 16

-10-20% cartilage
-chondroitin and keratin sulfate on protein core via link protein on hyaluronate backbone
-high affinity for water
-stiffness and strength
-provides compressive strength

Front 17

Increased age is accompanied by an increase in which GAG?

Back 17

Keratan Sulfate

Front 18

primary nutrition for articular cartilage?

Back 18

diffusion from synovial fluid

Front 19

Chondrocyte metabolism?

Back 19

-synthesize and maintain matrix
-Decreased metabolic rate w age
-rarely divide after skeletal maturity
-anaerobic metabolism

Front 20

Why articular cart healing diff than other tissue?

Back 20

-avascular
-chondrocyt unable to migrate to defect

Front 21

Artic cart response to partial thickness injury?

Back 21

-brief increase in matrix synthesis from adjacent chondrocytes
-no significant healing

Front 22

Full thickness artic cart injury healing response?

Back 22

-defect is filled with fibrin clot and undifferentiated mesenchymal cells
-reparative tissue develops into 'hyaline-like" tissue
-by 6-12 months fibrocartilage is present, which develops surface fibrillation with time.

Front 23

Cart injury and repair process if subchondral bone is penetrated?

Back 23

-reparative response w fibrin clot,m cell migration from bone marrow, vascular ingrowth.
-fibrocatrilage formed w Type I collagen, less organized and vore vascular and biomechanically different than hyaline cartilage. Mechanically less durable and more likely to degenerate
**mesenchymal stem cells come from bone marrow.**

Front 24

What MRI setting look for articular cartilage injuries?

Back 24

T2 (T1 will not show articular cart injuries)
-*need proton density imaging of thin sections and T2-weighted imaging with fat suppression sequencing.
-high relolution gradient echo/fast spin echo
-Gadolinium enhances matris/GAG imaging

Front 25

Outerbridge classification chondromalacia?

Back 25

-I Softening
-II Fibrillation
-III Fissuring (but does not go down to subchondral bone)
-IV Complete loss with exposed bone

Front 26

Articular cart indications for surgery?

Back 26

-traumatic, nondegen lesion active pt <55yo
-lesion <1cm
-symptomatic Gr IV lesions
-symptomatic OCD in adolescents
-symptomatic OCD in adults

Front 27

Microfx technique?

Back 27

-best for contained, small, Gr 4 lesions
-3-4mm perforations separated by 5mm
-need to debride (curette) calcified cartilage
-NWB x 6 wks
-CPM helpful?

Front 28

OCD: cart and bone?

Back 28

Bone is dead, cartilage is alive.

Front 29

OCD: M/F?
joints affected?
%bilateral?

Back 29

-M/F is 2:1
-knee, ankle, and elbow
-15-30% bilateral

Front 30

Nat Hx juvenile v adult OCD?

Back 30

-Juvenile will usually heal with non-operative treatment
-Adult OCD will rarely heal with non-operative treatment.

Front 31

Indications ORIF OCD?

Back 31

-reducible OCD
0.5-1.0 cm2 or larter
-use minifrag or headless screws
-curette soft tissue from base of crater and drill to stimulate bleeding

Front 32

Ideal OATS lesion?

Back 32

-focal
-contained
-traumatic or OCD
-1-3 cm2 (<2cm best)
(speaker doesn't harvest more than 2 of these small grafts)

Front 33

Osteochondral Allograft Transplantation indications?

Back 33

Best results in single, well-demarcated, full thickness, osteochondral defects of 2-5cm in your patient with an otherwise normal knee
-multiple lesions
-AVN of condyles
-large OCD

Front 34

15-20 year survivorship osteochondral allografts?

Back 34

looks good at this time.

Front 35

Autogenous Chondrocyte Implantation (ACI) indications?

Back 35

-focal art car lesions of femoral condyles of knee
-large w full-thickness articular cart loss (w or w/o subchondral bone loss - ie OCD)
-failed previous art cart treatment such as microfx, OATS

Front 36

technique of periosteal flap sewn to cartilage for ACI?

Back 36

periosteal flap sewn w 6-0 Vicryl w cambium later facing subchondral bone

Front 37

ACI Indications II?

Back 37

-failed OCD repair
-large lesions 2-10cm2
-<6mm subchoncdral bone loss
-age 15-55
-Normal alignment
-no obesity
-no inflammatory disorders
-no sensitivity to gentamycin or bovine serum

Front 38

Articular cart aging?

Back 38

-size of proteoglycan aggregates decreases
-affrecan molecules become shorter as do their chondroitin sulfate chains
-mean # aggrecans in each aggregate decreases
-decreased water concentration

Front 39

Concentration Chondroitin-4 sulfate w age?

Back 39

decreases w age

Front 40

Concentration Chondroitin-6 sulfate concentration w age?

Back 40

Increases

Front 41

concentration Keratan sulfate w age?

Back 41

increases

Front 42

Apparent cause of cart breakdown in aging joints?

Back 42

action of proteolytic enzymes (proteinases) that are synthesizd by the chondrocytes

Front 43

**Articular cartilage changes with DJD?

Back 43

-AC fibrillation
-increased water content
-decreased proteoglycan
-increased permeability
-decreased stiffness

Front 44

Viscosupplementation efficacy?

Back 44

synvisc v Celestone: no sig diff in pain relief or function at 6 months follow-up

Front 45

Indications osteotomy?

Back 45

-unicompartmental disease
-young pt (5th-6th) decade
-stable knee
ROM - full extension, flex to 90 or greater.

Front 46

osteotomy site for:
varus?
valgus?

Back 46

varus - HTO
valgus - HTO < 12 deg
DFO if >12 deg

Front 47

Def Aptosis?

Back 47

chondrocyte death

Front 48

SONK?

Back 48

Spontaneaous OsteoNecrosis of the Knee

Front 49

SONK presentation?

Back 49

-middle age female following arthroscopy
-usually one compartment, unilateral
-ass'd w subchondral deficiency
-sudden onset of pain
-MFC most commonly affected
-Dx by MRI
-Rx is NWB, 3-6 months!
-do NOT scope again

Front 50

AVN of knee DDx?

Back 50

-SONK
-OCD
-Bone Bruise
-Transient osteopenia

Front 51

AVN of knee presentation?

Back 51

-over 45yo, F>M
-multiple compartments
-bilateral
-gradual onset
-ass'd w sickle cell, steroids, EtOH

Front 52

Knee accessory arth portal: posteromedial: where? Structure at risk?

Back 52

1 cm above joint line
inj risk to saphenous nerve

Front 53

knee accessory arth portlal: where? structure at risk?

Back 53

-knee in flexion stay 1 cm above joint line and stay above biceps.
-inj risk to peroneal nerve

Front 54

Normal synovium:layers?

Back 54

1) the intimal layer: synoviocytes, production of synovial flluid content
2) the subintimal supportive layer - fibrous and adipose tissue with a rich capillary network

Front 55

Cell types in normal synovium?:

Back 55

Type A(25%): tissue macrophage, phagocytic function
Type B(75%) secretion of hyaluronate -

Front 56

Composition of synovial fluid?

Back 56

-dialysate of blood plasma without clotting factors, RBC, HgB
-Hyaluronate (extended GAG)
-Lubricin (lubrication glycoprotein)

Front 57

Biomechanices of synovial fluid?

Back 57

-viscosity coefficient is not constant but depends on shear rate
-as shear rate increases, viscosity decreases (this is due to the presence of hyaluronate molecues that entangle to form elastic network, or "stringiness")

Front 58

Elastohydrodynamic lubrication?

Back 58

under loading of cartilage there is "elastic" deformation which then spreads the going load over a larger surfae area
-decreases shear rate

Front 59

Boundary Lubrication?

Back 59

-works when fluid film depleted
-monolayer of glycoprotein (lubricin) is adsorbed on each of the opposing articular surfaces
-porvides cushioning and protects against abrasion

Front 60

Synovial chondromatosis presentation?

Back 60

-cart tissue converted to ossified loose bodies
-usually middle-aged men
-pain, mech Sx, dec motion
-knee #1, elbow #2
-Rx complete synovectomy.
-recurrence >25%

Front 61

PVNS presentation?

Back 61

-slow growing, benign, locally invasive timor of synovium
-usually presents as monoarticular hemarthrosis
-most have hemorrhagic, dark brown synovial fluid
-**Biopsy is diagnostic
-Mechanical symptoms

Front 62

MRI DDx PVNS?

Back 62

-hemophilic arthropathy
-fibromatosis
-synovial chondromatosis
-septic or inflammatory arthritis
-hemorrhagic synovitis

Front 63

PVNS histopath?

Back 63

lipid-laden foam cells and multinucleated giant cells are interspersed with hemosiderin-laden cells. Sinilar to GCT of tendon sheath.

Front 64

Gout ass'd diseases?

Back 64

-EtOHism
-obesity
-HTN
-CAD
-hypertriglyceridemia

Front 65

Gout: Rx and recurrence?

Back 65

-thiazide diuretics and antimetabolites
-remits and recurs with high rate of recurrence

Front 66

Gout synovial fluid?

Back 66

-inc WBC like in infx
-**needle-like intracellular and extracellular monosodium urate crystals seen under polarized light microscopy

Front 67

Pseudogout presentation?

Back 67

>50yo,
knee and wrists
chondrocalcinosis of menisci
CPPD crystals are weak pos birefringence, rhomboib shape

Front 68

Synovial fluid analysis: WBC?

Back 68

JRA 15k-80k
septic arthritis >50k
gout/pseudogout -high but fluid usually less turbid
`

Front 69

Synovial fluid analysis: crystals?

Back 69

Gout: negatively birefringement needles on polarized micro
Pseudo: rod-shapled or rhomboib with weak positive birefringecy

Front 70

Tibial eminence Fx classification, Rx?

Back 70

I - minimally displaced - peds, nonop imm ob 6-8 weeks
II - fragment elevated but still attached - same Rx as I
III - complete displacement of the fragments - usually ORIF

Front 71

Most common location for osteochondral injury due to acute lateral patellar dislocation?

Back 71

medial patellar facet

Front 72

14yo w OCD MFC w intact articular cartilage. 4 mo's PT with no improvement. Best option for treatment?

Back 72

arthroscopic drilling

Front 73

11yo w displaced tibial eminence fx - Rx?

Back 73

arthroscopic reduction and fixation

Front 74

Open posteromedial approach to avulsion fx post cruciate ligament tibial insertion. How protect posterior NV bundle?

Back 74

Retraction of medial heard of the gastrocnemius muscle laterally (P352, look up)

Front 75

30 yo jockey failed microfx for 3x4cm bare bone artic cart lesion of MFC. Best treatment?

Back 75

Osteochondral allograft

Front 76

32yo beach VB w artic crt lesion of bare bone 1cm2. Microfx technique: most important technical step?

Back 76

the calcified cartilage layer must be removed.

Front 77

What is type collagen resulting from microfx?

Back 77

Type I

Front 78

14yo Basketball player w knee pain due to OCD femoral condyle. Pain began previous season. No trauma. No response to 6 weeks dec activity. Next step?

Back 78

Surgica intervention (p355)

Front 79

12yo w OCD w catching and effusions. Most common location of lesion?

Back 79

Posterolateral aspect of MFC>
p 356

Front 80

22 yo basketball player w OCD trochlea. Next step?

Back 80

arthroscopic eval and treatment.
p357

Front 81

33yo w loaclized PVN. Treatment?

Back 81

Arthroscopic excision of the focal lesion (total synovectomy not necessary, p 357)

Front 82

13yo w patellar dislocation, MRI shows displaced osteochondral fragment from LFC. Treatment?

Back 82

ORIF LFC artic cart fragment

Front 83

The structure of cartilage proteoglycans can be described as:

Back 83

Multiple glycosaminoglycans bound to core portein, which is subsequently bound to hyaluronate vie a link protein

Front 84

Fluid within a cartilage layer is pressurized under dynamiic joint motion because of what factor?

Back 84

Low hydraulic permeability of the tissue.
p360

Front 85

Compared with the surface of articular cartilage, the deeper layers have which characteristics (Q23 p 360)?

Back 85

An increase in chondrocyte volume and collagen fibers perpendicular to the joint surface

Front 86

Factor not associated with the limited capacity of cartilage to heal following injury?

Back 86

No initial response by chondrocytes to injury (?)
p 360

Front 87

Coefficient of frictoin between articulating surfaces in the healthy human hip is in general range of___?

Back 87

0.002 to 0.04

Front 88

Most likely mechanism of lubrication responsible for very low coefficient of friction in articular surface?

Back 88

Elastrohydrodynamic