Knee Flashcards
which of the menisci is fixed?
medial meniscus
what do menisci do?
distribute load from convex femoral condyles to relatively flat tibial articular surfaces
which plateau is slightly more concave?
medial
what does the MCL resist?
valgus stress
what does the LCL resist?
varus stress
what does the ACL resist?
anterior subluxation of the tibia /femur
hyperextension of the knee
what can an MCL rupture lead to?
valgus instability
what can an ACL rupture lead to?
rotatory instability
what can an PCL rupture lead to?
recurrent hyperextension or instability descending stairs
what can an posterolateral corner rupture lead to?
varus & rotatory instability
which kinds of patients usually have meniscal tears?
sporting injury in younger patients or getting up from squatting in younger patients
which patients can you see an atraumatic meniscal tear in?
spontaneous degenerate tears in older patients (40+)
what associated injury to 50% of ACL ruptures have?
meniscal tears
how would you investigate a meniscal tear?
MRI
which side is more commonly torn in meniscal tears?
medial
how would you repair a meniscal tear?
arthroscopic repair
how you repair a meniscal tear with mechanical symptoms (pain/catching), irreparable tears or failed meniscal repair?
arthroscopic menisectomy
what does acute locked knee signify?
displaced bucket handle meniscal tear
what is required with a displaced bucket handle meniscal tear?
urgent surgery (arthroscopic repair/partial meniscectomy)
what can develop if a knee remains locked?
FFD
what does a degenerate meniscal tear probably signify?
1st stage of OA
what’s a grade 1 knee ligament injury?
sprain
tear some fibres but macroscopically still intact
what’s a grade 2 knee ligament injury?
partial tear
some fascicles disrupted
what’s a grade 3 knee ligament injury?
complete tear
describe what the healing like with an MCL injury?
usually heals well even if completely torn unless combined with ACL/PCL rupture
how would you treat an MCL injury?
brace
early motion
physiotherapy
how does ACL rupture usually come about?
sports injury - football, rugby, skiing
how do you treat ACL rupture?
reconstruction
- autograft
- allograft
- synthetic graft
how does an LCL injury usually come about?
varus stress & hyperextension
describe the healing of an LCL injury?
doesn’t heal & can cause various & rotatory instability
what nerve damage can occur in LCL injury?
peroneal nerve palsy
what does an LCL injury often occur in combination with?
PCL/ACL injury
when would urgent repair be required in an LCL injury?
if complete rupture occurs
how does a PCL rupture usually occur?
direct blow to anterior tibia (dashboard/motorbike) or hyperextension injury
what will be seen clinically with PCL rupture?
popliteal knee pain & bruising
what complications can occur with knee dislocation?
popliteal artery injury
nerve injury
compartment syndrome
what’s required fro knee dislocation to occur?
serious high energy injury
how does patellar dislocation occur?
rapid turn or direct blow
in which patient groups is patellar dislocation more likely?
females adolescents ligamentous laxity valgus knee torsional abnormalities
what can patellar dislocation cause?
chondral or osteochondral injury
how can extensor mechanism rupture occur?
all onto flexed knee with quads contracted
what will you usually find in the history of a patient with extensor mechanism rupture?
previous tendonitis
steroids
chronic renal failure -> ciprofloxacin
what will be found clinically in extensor mechanism rupture?
unable to straight leg raise
palpable gap
how is extensor mechanism rupture treated?
requires surgical repair
haemarthrosis
knee fills up with blood, comes up within an hour, causes generalised pain across the knee
effusion
comes up the following day
what does a haemarthrosis suggest?
ACL, fracture or very peripheral meniscal tear
what does an effusion suggest?
meniscal or chondral injury
what does pain along the joint line mean?
meniscal or chondral injury or a generalised haemarthrosis
what does hyaline cartilage do within a knee?
decreases friction & distributes load
which type of articular cartilage injury can heal?
only full thickness injuries can heal
how does hyaline cartilage heal?
with fibrocartilage which has greater friction & is less wear resistant
what atraumatic articular cartilage defects can occur?
osteochondritis dissecans
ostoearthritis
inflammatory arthritis
osteochondritis dissecans
an area of the surface of the knee loses its blood supply & cartilage +/- bone can fragment off
when is osteochondritis discerns most common?
in adolescence
what are the options of techniques for cartilage regeneration?
drilling/microfracture
osteochondral autograft/allograft
mosaicplasty
MACI
MACI
membrane induced autologous chondrocyte implantation
which compartment does load go through in varus knees?
medial compartment
which compartment does load go through in valgus knees?
lateral compartment
