Adult Knee Problems Flashcards
what does the knee consist of?
medial and lateral tibiofemoral articulations and the patellofemoral joint
what are the bone surfaces covered with in the knee joint?
articular (hyaline) cartilage
what does the tibiofemoral joint contain?
fibrocartilage menisci
what does the extensor mechanism consist of?
tibial tuberosity patellar tendon patellar quadriceps tendon quadriceps muscle
what action causes rupture of the extensor mechanism?
fall on a flexed knee with quadriceps contraction
what is damaged in an extensor mechanism rupture?
quadriceps ligament
patellar tendon
what age is the quadriceps ligament more likely to be damaged?
> 40
what age is the patellar tendon more likely to be damaged?
<40
predisposing factors for tendon rupture
tendonitis quinolone antibiotics chronic steroids DM RA chronic renal failure
presentation of extensor mechanism rupture
unable to straighten leg (SLR)
palpable gap
diagnosis of extensor mechanism rupture
XR high patellar is patellar tendon
XR low patellar is quadriceps tendon
management of extensor mechanism rupture
surgical repair
what is patellofemoral dysfunction?
excessive grinding of the patella on the femur
presentation of patellofemoral dysfunction
anterior knee pain worse going downhill
grinding or clicking sensation at front of knee
prolonged sitting leads to pseudo-locking where knee stiffens in flexed position
management of patellofemoral dysfunction
physio to rebalance quads
tapping
surgery is last resort to release tight lateral retinaculum
what causes a patellar dislocation?
sudden blow or twist of knee
most common direction of the patella in dislocation
lateral
can reduce when knee is straightened
what increases the risk of patella dislocation?
hypermobility
under-developed lateral femoral condyles
increased Q angle
weak vastus medialis
diagnosis of patellar dislocation
XR can show small opacification where patella strikes the lateral femoral condyle
presentation of patellar dislocation
most have reduced themselves
lipohemarthrosis
management of patellar dislocation
risks reoccurrence
physiotherapy to strengthen quads
what causes a meniscal tear?
twisting force on a loaded knee
common causes meniscal tears
sports
getting up from squat
which side tears are more common?
medial
types of tears
- longitudinal > bucket handle
- radial > parrot beak/oblique
- horizontal > flap tear
what can a bucket handle mensical tear cause?
it can displace and prevent extension
presentation of a meniscal tear
localised pain in joint line
effusion day after
catching/locking sensation
what happens if difficulty straightening the knee persists?
fixed flexion deformity (FFD)
diagnosis of meniscal tear
Steinmann’s test
MRI
what happens in Steinmann’s test with a lateral meniscal tear?
pain in internal rotation and extension at 90 degrees
management of meniscal tears
only outer 1/3rd has blood supply so need to do arthroscopic meniscectomy steroids injections (NEVER into tendon)
what causes an ACL rupture?
high rotational force
presentation of ACL rupture
pop that is felt or heard deep pain in knee hemarthrosis rotatory instability feeling the knee could give way
diagnosis of ACL rupture
Lachman’s test (tibia can be pulled forward on femur when knee is flexed)
management of ACL rupture
reconstruction and intensive rehab
what causes MCL rupture?
valgus stress
presentation of MCL rupture
laxity
pain when stretched
tenderness over origin and insertion
management of MCL rupture
tend to heal well so early motion and physio
if chronic instability then reconstruction
what causes LCL rupture?
varus stress
is LCL rupture common?
no
management of LCL rupture
doesn’t heal well so urgent reconstruction
what causes a PCL rupture?
direct blow on anterior tibia with flexed knee OR
hyperextension
what are the risks in PCL rupture?
peroneal nerve injury
popliteal artery incident
what does peroneal nerve injury present with?
foot drop
presentation of PCL rupture
instability descending stairs
pain
bruising
management of PCL rupture
tendon graft surgery
who is most likely to dislocate their knee
teenage girls
complications of knee dislocation
popliteal artery
peroneal nerve
compartment syndrome
CHECK CIRCULATION OF FOOT
management of knee dislocation
urgent surgical repair
