11/8 - Articular Cartilage Lesions Flashcards
OA vs articular cartilage lesions
OA - larger, broader scale of damage
articular cartilage lesions more localized
what are 2 functions of articular cartilage
- provides low friction wt bearing surface (low coefficient of friction)
- absorbs shock
what does it mean that articular cartilage is aneural and avascular
lacks inflammatory phase
minimal ability to repair/regen
role of chondrocytes
orchestrate matrix balance
what is the tidemark in cartilage
junction of calcified articular cartilage w subchondral bone
- aka transition from cartilage to bone
describe lesion classification of articular cartilage
type 1 = softening
type 2 = fibrillation
- superficial damage
type 3 = fissuring to bone
type 4 = full thickness
how to dx a type 1 articular cartilage lesion
via arthroscopy and probe surface to detect softening
MOI of articular cartilage defects is similar to what other injuries
meniscal tears
ligamentous injuries
why are XRs used as diagnostic imaging in articular cartilage lesions
can’t appreciate cartilage damage
looking to see where bone is taking more load than should be (whiter area = bony edema)
what is an important view to take XR from for articular cartilage damage
in a WBing view
- look at space b/w femur and tib -> can estimate amt of cartilage between
what diagnostic imaging can appreciate the cartilage defect
CT scan
size classification of articular cartilage lesions
small <2cm
mod 2-10cm
large >10cm
what relationship does the size of the defect have w the surgical procedure
bigger it is = worse it is = more challenging the procedure
depending on size makes surgeries more or less appropriate
what is a consideration when measuring the size of the lesion
lesions are larger than they seem
- once you debride all unhealthy tissue there is a greater area underneath
could see this on an MRI
what are 7 non-surgical options for articular cartilage lesions
NSAIDs
glucosamine/chondroitin sulfate
cosamin DS
viscosupplementation
bracing
orthotic therapy
exercise
what is the purpose of taking glucosamine / chondroitin sulfate
building blocks of articular cartilage
what is the purpose of taking cosamin DS / osteobioflex
components of articular cartilage
- does NOT form NEW cartilage
what is viscosupplementation and what is the duration
hyaluronic acid injections
6-12mo pain relief
what cases are unloader braces helpful in
isolated lesions on one side
what is the purpose of bracing in articular cartilage lesions
change mechanical stresses at impacted knee compartment
what is the purpose of orthotic therapy in articular cartilage lesions
change axis of stress at joint
- ex: wedge in shoe
with articular cartilage lesions what is the goal of exercises
ms that act to absorb shock
provide normal environment around knee
what are 4 surgical options for articular cartilage lesions
bone marrow stim
osteochondral transplantation
cellular therapy
matrices/scaffolds
what is bone marrow stimulation
abrasion, drilling, micro fx
- create bleeding environment to facilitate fibrocartilage growth
what are osteochondral transplantation options for articular cartilage lesions
autologous:
- OATS
- mosaicplasty
allograft
what is cellular therapy in articular cartilage lesions
autologous - MACI
what is the purpose of matrices and scaffolds in articular cartilage lesions
preserve cartilage and protect it
what can dictate healing potential from an articular cartilage lesion and what is the significance of someone’s healing potential
declines w age
depends on comorbidities:
- DM, smoke, drink
all this factors into if they are a better or worse candidate for surgery
why does the location of the articular cartilage lesion matter
plays a role in degree of motion that engages with the lesion and creates sx
what is arthroscopic debridement / chondroplasty
remove loose fragments to dec irritation and dec pain
incidence of chondroplasty procedures
not done often any more
what pt is chondroplasty optimal in
if low demands on knee
fibrocartilage replacement of hyaline cartilage defects?
fibrocartilage isn’t as strong or desirable
- but better than no cartilage
how does microfracture work as a surgical procedure
stim marrow stem cells
- create fibrin clot -> fibrocartilage growth
collagen consistency in hyaline vs fibrocartilage
hyaline: types II, IX, XI
- organized fiber orientation
- organization allows to be stronger and more resilient to compressive and shear forces
fibro: type I
- unorganized fiber orientation
is hyaline or fibrous cartilage stiffer
hyaline 2x stiffer than fibrous
what are 4 advantages of microfracture
- single stage procedure
- ease of procedure
- cost effective
- doesn’t “burn any bridges”
- if fails, though that could go back in and do another procedure but not necessarily the case
what are 2 disadvantages of microfracture
final product is fibrocartilage
- limited durability
inferior results in lesions >4cm (size matters lol)
what are 4 success criteria in microfracture
- young patient (<35-40)
- small area
- <2cm, contained - less WBing surface
- BMI <25
articular cartilage lesion that is contained vs shouldering
contained
- smaller
- not a tone of load at subchondral bone
shouldering
- margins further away
- load directly onto bone
ant vs post location of articular cartilage lesion and WBing
post - less WB surface
- only when in deep flex
ant - loading when standing up straight
what is a consideration of the rehab process for microfracture when thinking ab pt goals
not a short process
- esp if have someone trying to get back to sports
after microfracture when does cartilage reach full maturation
6-12mo
what does WBing precautions after microfracture depend on
location and size of lesion
fem condyle (ant)
- FWB delayed to ~8wks
patellar/trochlear (post)
- WBAT in hinged brace w 10deg flex stop
return to high impact activity after microfracture
up to 8mo for large lesions
4-6mo in small lesions
what is the key to rehabing a microfracture
create healing environment without overloading healing tissue
goals for proliferation phase of microfracture rehab (3)
promote healing environment
control pain and swelling
work on PROM
what are the goals of the transition/remodelling phase of microfracture rehab (2)
- good ROM, work on strengthening (quads)
- inc functional activity
- weaning away from AD and bracing to more WBing
what is the goal of maturation phase of microfracture rehab
deliberate return to sport
what is the criteria for progression to gradually return to sport after microfracture (4)
full pain free ROM
80-90% strength
80% balance
no pain, swelling
what is the criteria to start working on strengthening after microfracture (4)
full passive ext
125deg knee flex
min pain/swelling
voluntary quad contraction
what happens during an OATS procedure
transfer healthy cartilage from minor load bearing surface to lesion
what is the primary advantage to an OATS procedure
better quality of tissue than fibrocartilage bc transferring hyaline cartilage
what is a limiting factor as to whether OATS procedure is appropriate
size of lesion
- only so many places to harvest from that won’t be WBing
what is an advantage to an autograft OATS
faster incorporation bc pt’s own tissue
what is advantage to allograft OATS
slower bone incorporation bc not your own bone
- can be non-union
when is allograft vs autograft OATS more appropriate
allograft = larger defect
autograft = smaller
what is the success criteria for an OATS
optimal size of lesion <2cm
what is the usual harvest site for OATS
superior edges of trochlea
what dictates the WBing timeline after OATS
if lesion/graft on femoral condyle (more load bearing) or patellar/trochlear (bears less load)
