Knee Problems

Question 1

function of menisci

Answer 1

distribute load from convex femoral condyles to relatively flat tibial articular surfaces

Question 2

which meniscus is fixed

Answer 2

medial

Question 3

which meniscus is more mobile

Answer 3

lateral

Question 4

which compartment does the knee pivot on

Answer 4

the medial compartment

Question 5

function of MCL

Answer 5

resists valgus stress

Question 6

function of LCL

Answer 6

resists varus stress

Question 7

function of ACL

Answer 7

resists anterior subluxation of the tibia and internal rotation of the tibia in extension

Question 8

function of PCL

Answer 8

resists posterior subluxation of the tibia (or anterior subluxation of the femur) and hyperextension of the knee

Question 9

when do meniscal tears usually occur in younger people

Answer 9

sports injury

Question 10

what accompanies 50% of ACL ruptures?

Answer 10

meniscal tear

Question 11

how should you investigate ligament or meniscal tears?

Answer 11

MRI

Question 12

which meniscus is more likely to tear?

Answer 12

medial (10x more likely)

Question 13

why do meniscal tears have limited healing potential?

Answer 13

only the peripheral 1/3 has blood supply

Question 14

which pattern of meniscal tear will not heal?

Answer 14

radial

Question 15

what treatment should be considered in young patients with acute peripheral tears?

Answer 15

arthroscopic repair

Question 16

what does an acute locked knee signify?

Answer 16

displaced bucket handle meniscal tear

Question 17

how is a suspected bucket handle meniscal tear assessed clinically

Answer 17

heel height test

Question 18

what treatment is given for bucket handle meniscal tear

Answer 18

urgent surgery - either arthroscopic repair or a partial menisectomy

Question 19

what are degenerate meniscal tears a sign of?

Answer 19

early sign of OA

Question 20

grade 1 ligament injury

Answer 20

sprain - some fibres torn but macroscopic structure remains in tact

Question 21

grade 2 ligament injury

Answer 21

partial tear - some fascicles disrupted

Question 22

grade 3 ligament injury

Answer 22

complete tear

Question 23

features of MCL injury

Answer 23

usually heal well
not the case when combined with ACL or PCL rupture
treatment with knee brace, early motion and physio

Question 24

which ligament is the main stabiliser against internal rotation of the knee

Answer 24

anterior cruciate ligament

Question 25

can the ACL be repaired?

Answer 25

no it must be reconstructed

Question 26

how is the ACL reconstructed

Answer 26

autograft from patellar tendon or hamstrings | allograft from achilles tendon

Question 27

1/3 rule of ACL injury

Answer 27

1/3 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 meaning they will never return to high impact sport

Question 28

what percentage of ACL ruptures end up having surgical reconstruction

Answer 28

40%

Question 29

when do LCL injuries occur

Answer 29

excessive varus and hyperextension | relatively uncommon

Question 30

will the lateral collateral ligament heal

Answer 30

no - can therefore cause varus and rotator instability

Question 31

in what condition is there a high incidence of LCL injury

Answer 31

common peroneal nerve palsy

Question 32

what commonly occurs in combination with LCL injury

Answer 32

PCL or ACL injury

Question 33

what causes a PCL injury

Answer 33

direct blow to the anterior tibia, or a hyperextension injury

Question 34

how does PCL injury present

Answer 34

popliteal knee pain and bruising

Question 35

consequences of PCL injury

Answer 35

instability, recurrent hyperextension, feeling unstable going downstairs

Question 36

what causes knee dislocation (not patellar)

Answer 36

serious, high energy injury

Question 37

complications of knee dislocation

Answer 37

popliteal artery injury nerve injury compartment syndrome

Question 38

what causes patellar dislocation

Answer 38

rapid turning or direct blow

Question 39

risk factors for patellar dislocation

Answer 39

``` female adolescent ligamentous laxity valgus knee torsional abnormalities ```

Question 40

in what percentage of people does patellar dislocation recur?

Answer 40

10%

Question 41

what causes an extensor mechanism rupture

Answer 41

fall onto a flexed knee with quadriceps contraction

Question 42

risk factors for extensor mechanism rupture

Answer 42

``` previous tendonitis steroid use chronic renal failure rheumatoid arthritis diabetes ciprofloxacin use ```

Question 43

features of haemarthrosis

Answer 43

usually warm generalised pain swelling within an hour usually associated with ACL rupture or fracture

Question 44

features of effusion

Answer 44

develops over a period of 24hr | associated with meniscal or chondral injury

Question 45

what is osteochondritis dissecans

Answer 45

atraumatic cartilage defect which occurs when an area of the surface of the knee loses its blood supply and the cartilage +/- bone can fragment off

Question 46

what happens during cartilage healing

Answer 46

healing is with fibrocartilage rather than hyaline cartilage which has greater friction and less wear resistance

Question 47

name 4 cartilage regeneration techniques

Answer 47

drilling/microfracture osteochondral autograft/allograft mosaicplasty MACI - membrane induced autologous chondrocyte implantation

Question 48

which cartilage regeneration technique is simplest and cheapest

Answer 48

microfracture

Question 49

which cartilage regeneration technique is used for larger defects/bone loss

Answer 49

osteochondral allograft

Question 50

predisposing factors to OA

Answer 50

articular cartilage injury, fracture, joint instability, genu varum/valgus, fracture malunion, degenerate meniscal tear, infection

Question 51

when is knee replacement done

Answer 51

older patients with end stage arthritis

Question 52

how long are new knees expected to last

Answer 52

15-20yrs

Question 53

what is injured in the unhappy triad

Answer 53

ACL, medial collateral ligament and medial meniscus

Question 54

typical mechanism of injury in meniscal tear

Answer 54

twisting force on a loaded knee

Question 55

when may pseudo locking occur

Answer 55

arthritis

Question 56

how do ACL injuries occur

Answer 56

high rotational force, turning upper body laterally on a planted foot

Question 57

joint line tenderness

Answer 57

feature of meniscal tear | assessed by Steinmanns test

Question 58

patterns of meniscal tear

Answer 58

longitudinal, radial, oblique and horizontal

Question 59

what may large longitudinal tears result in

Answer 59

bucket handle tear - means a large meniscal fragment is able to displace anteriorly or into the intercondylar notch

Question 60

examination findings ACL rupture

Answer 60

knee swelling | excessive anterior translation of the tibia on the anterior drawer/Lachman test

Question 61

when do osteochondral/chondral injuries occur

Answer 61

impact or shear of articular surface or due to a direct blow

Question 62

how should injuries involving large osteochondral fragments with a substantial portion of bone be fixed

Answer 62

fixed with pins

Question 63

how should injuries involving non-weight bearing areas be treated

Answer 63

arthroscopic removal

Question 64

how may the patellar or quadriceps tendon rupture

Answer 64

rapid contractile force which can occur after lifting a heavy weight, after a fall or spontaneously in a severely degenerate tendon

Question 65

who tends to be affected by patellar tendon rupture

Answer 65

younger patients (

Question 66

who tends to be affected by quadriceps tendon rupture

Answer 66

older patients (>40)

Question 67

what is patellofemoral dysfunction

Answer 67

disorders of the patellofemoral articulation which results in anterior knee pain

Question 68

what may also occur when the patella dislocates

Answer 68

medial patellofemoral ligament tear and osteochondral fracture lipohaemarthrosis