sofe tissue knee injuries Flashcards
what are the 4 mechanisms of knee injury?
extensor mechanism injury
meniscal tears
ligament injuries
knee and patellar dislocation
what is pseudolocking of a joint?
similar symptoms of locked knee when standing after long time sitting due to destruction of patellofemoral joint
who is an ACL injury most common?
women as hamstring torque doesn’t come on as quickly to resist twisting as it does in males
what can cause an extensor mechanism rupture?
fall onto flexed knee with quads contraction
quads tendon or patellar fracture or patellar tendon
what are the risk factors for extensor mechanism rupture?
previous tendonitis
steroid use
chronic renal failure, ciprofloxacin
how does an extensor mechanism rupture present?
unable to do straight leg raise
palpable gap
how is an extensor mechanism rupture treated?
requires surgical repair
what does an extensor mechanism rupture look like on imaging?
high patella is patella tendon rupture
can be in normal position of quadriceps tendon rupture
name 4 types of extensor mechanism rupture
rectus femoris tear
quadriceps tendon rupture
patellar fracture
patellar tendon rupture
most likely presentation of extensor mechanism rupture presentation?
elderly patient who is taking steroids for something else, stands up quickly/falls etc and has extreme pain
what is the function of the menisci?
shock absorber control synovial fluid lubrication well innervated in the periphery so can sense pain/damage etc distribute load evenly improve congruence of the joint
what are the 4 types of meniscal tear?
longitudinal
bucket handle (extension of longitudinal)
radial
parrot beak tear
common investigative surgery in the knee?
arthroscope
what can produce a meniscal tear?
usually sporting injury in younger patients or getting up from squatting position in younger position
can get atraumatic spontaneous degenerate tears in older patients (over 40)
what is a meniscal tear associated with?
50% occur with ACL rupture
where is a meniscal tear more common, medial or lateral?
medial
how is a meniscal tear treated?
radial tears wont heal
consider arthroscopic repair in acute peripheral tears in younger patient
consider arthroscopic menisectomy for mechanical symptoms
acute tears can be repaired in young patients
repair limited as only peripheral 1/3rd has blood supply
what signifies bucket handle meniscal tear?
acute locked knee
15 degree springy block to extension
how do you treat a bucket handle tear?
emergency surgery
does a surgical repair of meniscal tear always result in healing? why?
no
low blood supply
not exposed
lots of movement during healing
what is degenerate meniscal tear often a sign of?
first stages of OA
how do you manage a degenerative meniscal tear?
initial swelling will settle and may just get flares from time to time, or be asymptomatic
surgery can be done if very severe but produces bad results if OA is present
when should arthroscopic surgery be done for meniscal tear?
locked knee
when should surgery be considered for a meniscal tear?
acute injury with MRI proven meniscal tear
meniscal tear and corresponding symptoms
MCL and LCL function?
MCL = resists valgus stress LCL = resists varus stress
ACL and PCL function?
ACL = resists anterior subluxation of tibia and internal rotation of tibia PCL = resists posterior subluxation of tibia and external rotation of tibia
grade 1 knee ligament injury?
sprain - tear some fibres but macroscopic structure intact
grade 2 knee ligament injury?
partial tear
some fascicles affected
grade 3?
complete tear
grade 4?
knee dislocation
what happens in MCL rupture?
valgus instability
what happens in ACL rupture?
rotatory instability
PCL rupture?
recurrent hyperextension or instability descending stairs
what does posterolateral corner rupture lead to?
varus and rotatory instability
what can multiligament injuries result in?
gross instability
which is more likely to cause a haemoarthrosis, ACL or PCL rupture?
ACL
what causes a ligament rupture in general?
hyperextension of action (e.g tibia pushed back so far from injury/fall that the PCL cant resist it and snaps)
how can a collateral ligament injury affect the other side and how is this diagnosed?
increased pressure on the opposite side due to rupture of the other ligament can cause bleeding/bruising in the opposite condyle
lights up on imaging
how is MCL injury treated?
physio
bracing
early mobility
rarely needs surgery
how does an ACL injury usually occur?
sports injury
how is an ACL injury treated?
repair doesn’t work - reconstruction only (after settling)
- autograft - using hamstring or patellar tendon
- allograft - achilles
physio can stabilise ACL deficient knees
ACL can stick to PCL to stabilise
describe the outcomes of ACL rupture
1/3rd compensate and are able to function well
1/3 can avoid instability by avoiding certain activities
1/3 do not compensate and have frequent instability or cant get back to high impact sport
how many ruptured ACL cases need surgery?
40%
indications for ACL reconstruction?
rotatory instability not responding to physio
protect meniscal tear
patient keen to return to professional or high impact sport
does not treat pain or prevent arthritis
follow up of ACL reconstruction?
3 month to 1 year rehab
can cause infection and stiffness
some never get back to full sport and most have evidence of arthritis within 10 years
what causes an LCL injury?
uncommon
caused by hyperextension and varus
often occurs in combination with PCL or ACL injury
what causes a PCL rupture?
often in cyclists
direct blow to anterior tibia or hyperextension injury
rarely occurs alone
what does a PCL rupture look like?
posterior drawer (tibia sitting behind knee)
patella dislocation vs knee dislocation?
very different
knee dislocation very rare and bad news
what causes a knee dislocation?
serious high energy injury with high incidence complication
- popliteal artery injury
- nerve injury
- compartment syndrome
how is a knee dislocation treated?
emergency reduction, recheck neurovascular status
vascular surgery if needed
temporary stabilisation
multialignment reconstruction
what can cause a patellar dislocation?
rapid turn or direct blow
who is patellar dislocation more common in?
females
adolescents
people with ligamentous laxity
valgus knee
important questions in history?
what they were doing when the injury happened, what way it bent, sound they heard, what it looked like
what is ehlers danlos syndrome?
genetic connective tissue disease causing joint hypermobility
normal approach to OA?
non-pharmacological
sometimes pharmacological
is OA a uniform disease?
no
features of OA?
pain inflammatory flares stiffness loss of movement loss of function
when can OA often flare?
holiday knee
increased activity while on holiday and walking around unlike being at home where people more likely to drive everywhere
how is a LCL injury treated?
doesn’t heal on its own can cause varus and rotatory instability
complete rupture needs urgent repair if early (2-3 weeks)
later = reconstruction (using hamstring or other tendon)
how is a PCL rupture treated?
most isolated cases don’t need reconstruction
if part of multialignment knee injury, usually needs reconstruction
