Knee Problems + Trauma

Question 1

what type of joint is the knee

Answer 1

synovial joint

Question 2

what type of cartilage covers the surfaces of the knee joint

Answer 2

hyaline cartilage

- retropatellar thickest cartilage in body

Question 3

what is the function of the menisci in the knee

Answer 3

“shock absorbers” - act to distribute load evenly

Question 4

what 4 ligaments are in the knee

Answer 4

Anterior + posterior cruciate ligaments

Medial + lateral collateral ligaments

Question 5

what is the function of the ACL

Answer 5

ACL prevents abnormal internal rotation

Question 6

what is the function of the PCL

Answer 6

PCL prevents hyperextension

Question 7

what is the function of the MCL

Answer 7

MCL resists valgus force

Question 8

what is the function of the LCL

Answer 8

LCL resits varus force

Question 9

what problems in the knee may result in early OA

Answer 9

Meniscal tears
ACL rupture
Malaligment

Question 10

what side of the knee is affected by OA in genu varum

Answer 10

medial OA

Question 11

what side of the knee is affected by OA in genu valgum

Answer 11

lateral OA

Question 12

what treatment can help young patients with isolated medial compartment OA

Answer 12

osteotomy of proximal tibia

• bone cut for re-aligment
• shifts load to lateral compartment

Question 13

when should total knee replacements be considered

Answer 13

substantial pain + disability where conservative measures are no longer effective

Question 14

meniscal injuries classically occur due to what

Answer 14

twisting force on a loaded knee

Question 15

presentation of a meniscal injury

Answer 15

localising pain to medial / lateral joint line
effusion
knee locking - difficulty straightening leg
feeling of knee giving way

Question 16

which meniscus is more commonly injured

Answer 16

medial

- it is more fixed + less mobile than the lateral

Question 17

what causes true knee locking

Answer 17

mechanical block to full extension caused by torn meniscus becoming stuck in the joint line

Question 18

what is pseudo-knee locking

Answer 18

occurs in OA
knee joint becomes temporarily stuck with difficulty straightening
resolves spontaneously or patient will have developed trick to relieve the issue

Question 19

how do ACL ruptures occur

Answer 19

twisting injury- high rotational force

Question 20

presentation of ACL rupture

Answer 20

“pop” may be felt/ heard
haemarthrosis within 1 hour
deep pain
rotatory instability

Question 21

how do MCL ruptures occur

Answer 21

from a Valgus stress

e.g. rugby tackle from side

Question 22

how do PCL ruptures occur

Answer 22

“dashboard injury”

- direct blow to anterior tibia with knee flexed

Question 23

what is Steinmanns test

Answer 23

+ve in acute meniscal tears (young patients, high energy injury)
- pain on tibial rotation localising to the affected compartment

Question 24

meniscal tears are often related to what other injury

Answer 24

ACL rupture

Question 25

what is a bucket handle meniscal tear

Answer 25

large longitudinal tear flips out of normal position and becomes stuck in intercondylr notch -- locking of knee

Question 26

what is a degenerate meniscal tear? | what condition is it a sign of?

Answer 26

spontaneous tear / due to innocuous injury sign of OA Steinmanns test will be negative

Question 27

why do meniscal injuries have limited healing potential

Answer 27

only have blood supply to outer 1/3rd | healing potential decreases with age

Question 28

hallmarks of ACL rupture on examination

Answer 28

rotatory instability with giving way on turning +ve Lachmans test excessive anterior translation of the tibia on anterior drawer test

Question 29

what is important in treatment of ACL rupture

Answer 29

pysio!! | - same results as surgical reconstruction

Question 30

treatment of PCL rupture

Answer 30

conservative management | - only those with severe laxity / recurrent instability / frequent hyperextension will be considered for surgery

Question 31

how are MCL ruptures treated? | how well do they heal?

Answer 31

hinged knee brace | heal well - instability uncommon

Question 32

what other surrounding structures may also be damaged in an LCL tear

Answer 32

common peroneal nerve | popliteal artery

Question 33

a complete knee dislocation results from a rupture of what

Answer 33

rupture of all 4 ligament | - required surgery due to degree of instability

Question 34

what constitutes the extensor mechanism of the knee

Answer 34

tibial tuberosity patellar tendon quadriceps tendon quadriceps muscle

Question 35

how is the extensor mechanism tested

Answer 35

ability to perform straight leg raise = intact

Question 36

how is the extensor mechanism injured

Answer 36

rapid contractile force | e.g. after lifting heavy weight

Question 37

what antibiotics can increase risk of tendon rupture

Answer 37

quinolones

Question 38

what other things increase risk of extensor mechanism rupture

Answer 38

``` tendonitis chronic steroid use RA CKD Diabetes ```

Question 39

why should steroid injections be avoided in treatment of extensor mechanism ruptures

Answer 39

high risk of tendon rupture

Question 40

on Xray what would the following suggest 1. high lying patella 2. low lying patella

Answer 40

high lying - patella tendon rupture | low lying - quadriceps tendon rupture

Question 41

symptoms of patellofemoral dysfunction

Answer 41

anterior knee pain (worse going downhill) grinding/clicking at front of knee pseudolocking after long periods of inactivity

Question 42

treatment of patellofemoral dysfunction

Answer 42

pysiotherapy - particularly strengthening vastus medalis | taping may alleviate symptoms

Question 43

what might cause a patellar dislocation

Answer 43

direct blow | sudden twisting of knee

Question 44

what patients get distal femoral fractures? how do they occur?

Answer 44

osteoporotic bone - fall onto flexed knee

Question 45

why will a distal femoral fracture adopt a flexed position

Answer 45

pull from gastrocnemius muscle

Question 46

treatment of distal femoral fracture

Answer 46

fixed with plate + screws

Question 47

why is a complete knee dislocation a surgical emergency

Answer 47

high risk of vascular injury + nerve damage | high risk of compartment syndrome

Question 48

what type of fracture are tibial plateu fractures

Answer 48

intra-articular | - classified by schatzker system

Question 49

what nerve might be damaged in a medial tibial plateau fracture? what is the clinical sign?

Answer 49

common peroneal nerve -- Foot drop

Question 50

treatment of tibial plateu fracture

Answer 50

open reduction internal fixation