knee

Question 1

direct blow to the front of the knee will usually cause

Answer 1

PCL injury

Question 2

blows to the side of the knee will usually cause

Answer 2

collateral injury

Question 3

twisting injuries will usually cause

Answer 3

cruciate rupture or meniscal injury

Question 4

swelling immediately after injury usually suggests

Answer 4

haemarthrosis

Question 5

recurrent swelling with normal periods in between usually suggests

Answer 5

chronic internal derangement such as inflammatory arthritis or an old meniscal tear

Question 6

locking

Answer 6

limitations in extension although flexion is still possible
commonly caused by torn meniscus or loose body caught between articular surfaces
patient may describe being able to manipulate the knee around to unlock it

Question 7

instability

Answer 7

usually sugests ligamentous injury, but could also be capsular or muscle weakness

Question 8

how should you start the knee examination

Answer 8

patient standing
exposed joint above and below
exposed contralateral side for comparison

Question 9

knee examination - look

Answer 9

skin - scars, erythema, lacerations
soft tissue
- effusion most easily detected by absense of the dimple on the medal side of the patella
- muscle wasting of the quadriceps
alignment
- varus and valgus deformities
- genu ricavatum: knee hyperextension
- back of the knee: bakers cysts or popliteal anaeurysms
gait
- antalgic gait: short stance phase on affected side may be a commonn finding

Question 10

varus deformity may be due to

Answer 10

medial side of the joint affected by osteoarthritis

Question 11

fixed flexion deformity

Answer 11

position of comfort for the joint, may be due to acute infection

Question 12

knee examination - feel

Answer 12

sensation, palpating pulses and cap refil time
palpate soft tissue
palpate tibial crest, tibial tuberosity, patella tendon, patella margin, quadriceps insertion, collateral ligaments and joint capsule
palpate the popliteal fossa for swelling or palpable cyst
palpate along the medial joint line to assess for tenderness along the medial colateral ligament
palpate along the lateral joint line for tenderness along the lateral colateral ligament

temperature of the joint
stroke test for effusion: fluid is milked from the medial side of the knee up to the suprapatellar pouch, watch to see if the fluid returns

Question 13

knee examination - move

Answer 13

active and passive movement comparing both sides
proceed to special tests

Question 14

lag test

Answer 14

lift leg 10cm off the bed
bend knee 20 degrees and straighten again
if the quadriceps is weak they wont be able to straighten it again

Question 15

checking for posterior sag

Answer 15

compare the two tibial tuberosities with knees bent
if they’re not at the same level and there is posterior sag on one side, suspect PCL injury

Question 16

ACL draw test

Answer 16

after ensuring the patient has no foot pain, sit on the patients foot
place fingers in the popliteal fossa and thumbs on the ischial tuberosity
try to bring the tibia forward
repeat on the other joint and compare laxity

Question 17

lachman’s test

Answer 17

alternative to anterior draw test
knee flexed to 30 degrees
draw tibia upwards

Question 18

cruciate injury summary

Answer 18

Question 19

testing the stability of the collateral ligaments

Answer 19

bend knee at 30 degree angle
apply varus and valgus test

Question 20

which test is used to test for meniscal tears

Answer 20

McMurry’s

Question 21

McMurry’s test

Answer 21

flex knee to 90
medial: apply valgus stress, externally rotate and extend. Palpated or audible click indicates a medial meniscal tear
lateral: apply varus stress, internally rotate and extend. Palpated or audible click indicates lateral meniscal tear
poor sensitvity and can be painful

Question 22

test for propensity of patellar dislocation

Answer 22

patellar apprehension test

Question 23

patients with lax ligaments

Answer 23

more susceptible to patellar dislocation
knee is usually swollen, painful and may be difficult to examine
examine the normal knee to test for propensity to dislocate

Question 24

patellar apprehension test

Answer 24

test on normal knee for propensity to dislocate/lax ligaments
leg is held over the edge of the bed in an extended position
flexed while patellar is pushed laterally
patella may be encouraged to dislocate laterally, pateint will become veery anxious and the test should be stopped

Question 25

appley's test

Answer 25

patient lies prone tibia is compressed down and rotated into the examination table if there is more pain with compression than distraction the pathology is likely meniscal more pain with distraction is likely ligamentous

Question 26

special tests

Answer 26

lag test for quadriceps weakness check for posterior sag for PCL injury anterior draw test for ACL injury Lachman's test for ACL/PCL stabilty valgus/varus stress tests for stability of the collateral ligaments mcmurry's test for meniscal injury patellar apprehension test apley test for meniscal injury

Question 27

acute swelling ddx

Answer 27

post-traumatic haemarthrosis = immediate swelling, blood in the joint, painful warm and tense bleeding disorders acute septic arthritis traumatic synovitis aseptic non-traumatic synovitis (gout, pseudo gout, inflammatory arthropathy)

Question 28

chronic swelling ddx

Answer 28

intraarticular - osteoarthritis or inflammatory arthritis, synovil disorders eg. synnovial chondromatosis bony swelling - osteochondroma, osgood-schlatter, maligancy

Question 29

posterior knee swellinng ddx

Answer 29

baker's cyst - usually presents in older people with OA, occasionally will rupture and produce pain semimembranosus bursa popliteal aneurysm (there will be pulsation in the lump unless thrombosed

Question 30

baker's cyst

Answer 30

bulging of the posterior capsule and synovial herniation seen in the midline presents in older people with OA occasionally ruptures and causes pain

Question 31

semimembranosus bursa

Answer 31

bursa between semimembranosus and gastrocnamius resolves with time

Question 32

pulsation in posterior knee lumb

Answer 32

popliteal aneurysm will have pulsation unless thrombosed

Question 33

anterior knee swelling ddx

Answer 33

prepatellar bursitis infrapatellar bursitis other bursae

Question 34

prepatellar bursitis

Answer 34

front of the patella, often seen in workers who are often on their knees treatment consists of bandaging and avoiding kneeling occasionally aspiration is needed lump may need to be excised in chronic cases secondary infection is not uncommon

Question 35

ACL injury

Answer 35

most common knee ligament injury often ruptured playing sport commonly occurs when suddenyl changing direction or landing or twisting from a jump rare for the ACL to heal satisfactorily

Question 36

what does the ACL do

Answer 36

limits forward movement of the tibia on the femur also important for rotational stability

Question 37

why is it rare for the ACL to heal satisfactorily

Answer 37

because the synovial fluid around the ligament prevents formation of a clot required to promote healing response in the ligament

Question 38

examination of ACL injury

Answer 38

presents with haemarthrosis anterior draw test lachman's test pivot shift test

Question 39

ACL injury is confirmed with

Answer 39

MRI scan

Question 40

management of ACL

Answer 40

depends on age and activity younger patients under 22 - reconstruct everyone patients over 35 - try to treat non-operatively

Question 41

non operative management of ACL injury

Answer 41

conscious control over the knee to minimise rotational instability risk of repeated damage which can cause irreversible damage to the meniscus

Question 42

operative management of ACL injury

Answer 42

reconstruction hamstring tendon autograph hervesting common orthopaedic procedure with good success rate most common complication is re-rupture of the ligament this is reduced by diligent post operative rehabilitation and delaying return to sport by 9-12 months post-surgery

Question 43

surgery for meniscal teaar

Answer 43

if patient has mechanical symptoms of locking or catching repair or tear or menisectomy of the joint is locked and cannot be unlocked, this is an indication for semi urgent surgery

Question 44

predisposing factors of patellar dislocation

Answer 44

generalised ligamentous laxity underdevelopment of the lateral femoral condyle and flattening of the intercondylar groove maldevelopment of the patella, which may be too high or too small valgus deformity of the knee external tibial torsion a primary muscle defect

Question 45

initial management for patella dislocation

Answer 45

petella reduction - urgent because it is extremely painful RICE physiotherapy

Question 46

recurrent patella dislocation

Answer 46

first time dislocation is generally treated non operatively first episode is followed in 15-20% of cases with recurrent dislocation or subluxation after minimal stress

Question 47

management for recurrent patella dislocation

Answer 47

non-operative management - knee brace: not ideal for long ter due to quadriceps wasting - physiotherapy - patella taping operative treatment - repair/reconstruct

Question 48

osteoarthritis

Answer 48

knee is the commonest of the large joints to have OA often bilateral

Question 49

4 cardinal signs of OA on radiography

Answer 49

loss of joint space osteophyte formation subchondral sclerosis subchondral cysts

Question 50

non operative management of OA

Answer 50

activity modification, weight reduction using a stick or walker physio anti-inflammatory corticosteroid injections

Question 51

operative treatment of OA

Answer 51

knee replacement may be total or partial (unicompartmental knee replacement)

Question 52

unicompartmental knee replacements

Answer 52

advantage of preserving the ligaments patients feels the knee is more natural however if the artritis progresses to the other compartment it may need to be revised to total knee replacement to these surgeries have a higher revision rate