Knee patho (articular cartilage)- Dr Davies Flashcards
Chondral Injuries
one of the most common problems in the knee OA (the most common) RA OCD AVN
some of the things he talks about that can be found when looking for chondral changes
medial capsule
rough looking inside the joint
if theses a chunk missing in the cartilage (OCD)
*white defects on an MRI can be an OCD
Hallmarks of OA
Fairbank’s Changes
joint space narrowing
bones spurs
Sclerotic borders
Subchondral bone cysts
Non surgical treatment of OA
drug therapy exercise weight loss aerobic exericse foot wear surfaces PT (stretching, strengthening, etc) OA unloader braces nutrition supplements intra-articular injections (synvisc)
Intra-articular injections
Synvisc
its like the synovial fluid in the joint space
when a pt is walking on bone on bone (no cartridge), adding a fluid medium can decrease the contact force
the AAOS has come out saying that it is not helpful in controlled studies; however, Dr Davies has had so many pts that swear by them (can prolong getting surgery)
Knee Surgeries
Chondral Lesions Lavage Chondroplasty Microfracture Mosaiplasty- autograft OATS- autograft Osteochondral allograft ACI MACI DeVova
Classification system for the (layers of the bone) Articular cartilage defects
*be able to draw this* Articular Surface Superficial Tangential Zone (10-20%) Middle Zone (40-60%) Deep Zone (30%) Subchondral Bone
Superficial Tangential Zone (fibers alignment)
horizontal
Middle Zone (fiber alignment)
criss- cross- for support
Deep Zone (fiber alignment)
vertical
What are the different classification systems for grading articular cartridge
Outerbridge Classification
Kellgren and Lawrence Radiographic Criteria for Assessment of OA
ICRS (international cartilage repair society)
Grade 1 classification of cartilage
a little bit of fraying on the top in the superficial layer (mostly softening)
Grade 2 classification of cartilage
into the superficial layer and some into the middle layer
Grade 3 classification of cartilage
into the middle layer and some in the deep layer
Grade 4 classification of cartilage
subchondral bone
Bone Contusion
80-100% of pts who have an ACL injury will have a geographic bone contusion
*the femoral condyle will hit the tibial plateau when there is that pivot shift that injuries that ACL
Causes trabecular mirco-fractures that result from traumatic injuries to the bone, most commonly about the knee
Has significant impact on what we can do with rehab
Tibial Osteotomy
If they have malaligment, they will do an osteotomy to straighten out the tibia
If there is a lot of genu verum (causing pressure/ compression), they will go in and cut a wedge in order to straight out the tibia
There is no point to go in and fix the joint if there will still be a lot of pressure on that joint to cause more damage
Arthroscopic Lavage
*placebo effect (effective 15-70% of the time)
There is an inflow and outflow cannula to washout the joint. When there is degenerative stuff going on in the joint, there are little pieces of articular cartridge floating around in the synovium. This will cause irritation in the synovium, which causes the synovium to produce more fluid.
It is effective if it is only a grade 2; if it down to subchonrdral bone, it will not be effective.
*Is believed to remove the mediators of inflammation and any loose, free flaps, or pieces of cartilage that may be present; this will relieve the patients symptoms
Study by Moseley on Arthroscopic Lavage
3 groups: Arthroscopic debridement, Arthroscopic lavage, and placebo (just incisions on the skin)
*in the New England Journal Medical (level 1 study)
*the patients and assessors where blinded
At no point did either of the surgical intervention groups report less pain or better function than the placebo group
Surgical Treatment of Arthroscopic lavage (problem)
Literature doesn’t show it does a thing! and yet insurance is spending thousands and thousands to do this surgery.
*we cant get money for a fall prevention program (system is broken)
Chondroplasty
go in and trim off the excess and use a bur to smooth off the articular cartilage
*he doesn’t think it would help anything because it further decreases the amount of articular cartilage
Microfracture
One of the go to procedure because it is easy
*will use on an OCD lesion
Will trim all the margin out to make it smooth
Will use an awe (used to use a drill, but the heat would kill the chondrocyte cells around it)
Stimulates the mesenchymal stem cells to produce the fibrocartilage (instead of the original hyaline cartilage) at the subchondronal bone level
Mosaicplasty- autograft
similar to the OATS but Mosaicplasty uses small plugs
*used on OCD lesions
They will harvest bone plugs from a non-weight bearing, non-significant articulating surface, which is usually the superior lateral trochlea
Will fill in the gap if the gap of the OCD lesion with the bone plugs
OATS-autografts
Osteochondral Autograft Transfer System
Will harvest bone plugs from a non-weight bearing, non-significant articulating surface, which is usually the superior lateral trochlea.
These bone plugs will be larger than the mosaicplasty.
*better long term outcome than the mircofracture because it is true hyaline cartilage
Problem with Mosaicplasty and OATS
taking away bone in order to use it somewhere else
*Robbing Peter to Pay Paul
Will often weaken the bone; there has been times when fractures occur
Also, have to be careful to make sure that all the bone plugs are level. If they are not level, then a bump will be “proud.” This will create a rough articulating surface against the opposite surface.
Osteochondal allograft
When you have a large lesion, there may not be enough autograft tissue. It may be better to take the allograft tissue.
The lesion will be smoothed out before the allograft tissue will be inserted.
The allograft tissue can be sized exactly to the large lesion instead of having a few smaller plugs.
ACI (what does it stand for)
Autologous Chondrocyte Implantation
ACI
Genyzme or Carticel
Four generations
been around for quite a while
First Generation ACI
ACI periosteal patch
Have to go in and take a syringe to uptake the chondral cells from the pt
Will send the syringe and have the cells stimulated to multiple
Will prepare the base.
Will take a periosteal flap from the tibial plateau and sow the patch around the defect and inject the new cells into the patch.
Inject from the top; use lots of sutures; glue on top
Second Generation ACI
matrix ACI patch
Third Generation ACI
collagen based ACI patch
Fourth Generation ACI
gel based ACI
inject the cells into the gel so that the cells will not float away
DeNova
taking juvenile allograft tissue; kids who has passed away- takes the tissue and using this tissue instead of adult tissue
younger tissue heals faster/ much better quality tissue than older tissue
WIll put this tissue into the OCD to enhance the healing
Tissue Engineering
so much is happening now
ACI (gel based), etc
Return to activity (for different surgeries)
Chonrdroplasty: 2-4 weeks
Marrow stimulation/ Microfracture: 3-12 months
ACI: 14-18 months
Osteochondral autochondral/ allograft: 6+
TKA/ TKR
total knee replacement
end stage salvage procedure
older people
Compartments that can replaced in a TKR
Patellofemoral
Medial
Lateral
*if one is replaced- unicompartmental replacement/ partial knee replacement
Components in a TKR
Femoral (press fit or cemented)
Patellar (may or may not resurface)
Tibial stem
Surgical Incision for TKR
Tradition- 20-30 cm
Mini- 12-14 cm
MIS (muscle sparing)- 7-10 cm
TKR/TKA Rehab Protocols
Varies with pt Varies with MC Varies with co-morbidities Varies with type of procedures Varies with type of prosthesis
