Acute Knee Injuries

Question 1

What may cause an acute knee injury?

Answer 1

Fracture 
Acute on degenerate joint dx 
Meniscal injury 
Ligament injury 
Tendon injury

Question 2

What are important things to ask in your history for an acute knee injury?

Answer 2

Environment - sport/work/recreation
Activity - sports tackle/jumping for e.g.
Energy - how fast, how heavy?
Systemic symptoms (rigors, fever - thinking infection?)
Chronology - quick/slow onset, prev injuries or events?
Hear/feel a pop/crack
Swelling - how fast the swelling came on

Question 3

What would really fast swelling indicate?

Answer 3

Haemarthrosis (bleeding into the joint)

Question 4

Examination of acute knee injury

Answer 4

Look: scars, bruising, swellings, joint lines

Feel: effusion, crepitus, heat (inflammation), tenderness, tissue/lump defects

Move: passive/active, straight leg raise, range of movement, ligament testing and dynamic testing

Question 5

Why might it be difficult to examine a patient who you suspect as had a ligament injury but who is very muscly?

Answer 5

Muscles can compensate and stabilise the joint

Question 6

What form of imaging must you always do in acute knee?

Answer 6

XRays

Question 7

What can Xrays help you to identify?

Answer 7

Fractures 
Loose bodies 
Ligament avulsions 
Osteochondral defects
Degenerative joint disease
Lipohaemarthrosis (intra-articular fracture leads to bone/fat leakage from the bone marrow)

Question 8

What other investigations can you use?

Answer 8

USS and MRI

Question 9

When would you do an USS?

Answer 9

Not very often

Can be used to see tendon ruptures, some meniscal tears, swellings and cysts

Question 10

When would you use an MRI?

Answer 10

For clinical conformation it is the test of choice

Can be used to see ligaments and menisci
Not good for DJD or mobile pathology

Question 11

What would be a typical history of a meniscal injury?

Answer 11

Twisting movement on a loaded fixed knee

Squelch and pain
Gradual swelling
Painful to weight bear
Locked knee

Question 12

Which of the menisci is most likely to tear and why?

Answer 12

Medial menisci - as it is relatively immobile

Question 13

What is a typical history of a ACL tear?

Answer 13

Forward momentum on a fixed leg +/- rotation

Pop, immediate swelling
Often able to weight bear
Pain

Question 14

What is the best test for diagnosing ACL tear?

Answer 14

MRI

Question 15

How common is ACL tear?

Answer 15

1 in 3 people in high level sport will get this

Question 16

What is a typical history for a collateral tear?

Answer 16

Force to the side of the knee

No/minimal effusion
Bruise on one side
Feel of crack
Lateralised, sharp pain

Question 17

What is involved in the first aid care of an acute knee injury?

Answer 17

RICE, analgesia

Question 18

What other non-pharmacological management may follow RICE & analgesia?

Answer 18

Physiotherapy

Question 19

What is the goals of surgical treatment?

Answer 19

Joint preservation and to introduce as little to the joint as possible (which may fail)
Life-long care of joint

Question 20

What are indications for surgical treatment?

Answer 20

Failure of conservative Rx
Demands of work/sport
Interferes with activities of daily living
Prevention of further injuries or prevention of falls

Question 21

What are the three surgical methods of treating meniscal tears?

Answer 21

Meniscal repair
Partial Menisectomy
Meniscal transplant

Question 22

What are the indications for meniscal repair?

Answer 22

Young, sporty
Fresh tears (up to 3 months)
Health meniscus
Red/red or red/white zone

Question 23

Why does the tear need to be in the red/red zone or the red/white zone to qualify for meniscal repair?

Answer 23

These are the areas with higher vascularity and better chances of healing after repair

Question 24

Why might arthroscopic meniscal repair be preferred over open meniscal repair?

Answer 24

You can reach more central tears (greater accessibility)

Question 25

What are the various techniques for meniscal repair?

Answer 25

``` Open Outside-in Outside-out All inside Smith and Nephew ```

Question 26

Describe the smith and nephew technique for meniscal repair

Answer 26

Device passed through portal and meniscus to a depth that enables the T to be deployed, then knot tied outside the joint Knot pusher slides knots snuggly against meniscus

Question 27

What is the success rate of meniscal repair?

Answer 27

90% when its done on the right joint (i.e. injuries that will heal) 1 in 5 will fail/need re-arthroscopy and probable partial meniscectomy VAST majority of these tears are in the white zone

Question 28

What would occur if you removed the whole menisci?

Answer 28

Predisposes to bad OA

Question 29

What is involved in management of ACL tears?

Answer 29

1st line: ACL rehab | 2nd line: ACL reconstruction

Question 30

What is involved in ACL reconstruction?

Answer 30

Use tendon/fascia to fashion new ligament (allograft), feed this up through tibia and femur OR can try to stitch ACL back together

Question 31

What is involved in post-op care after ACL reconstruction?

Answer 31

Crutches, knee braces and physical therapy

Question 32

What are indications for ACL reconstruction?

Answer 32

Prevention of further injury/OA | Back to work/sport

Question 33

What is an osteochondral injury?

Answer 33

Injury to the cartilage and bone underneath

Question 34

How can you surgically manage an osteochondral injury?

Answer 34

Debridement Reattachment of loose bodies Microfracture chondroplasty Artificial cartilage implantation

Question 35

What is involved in microfracture chondroplasty?

Answer 35

Puncture little holes into the bone and this causes bleeding --> clot formation and fibrous repair (not as good as cartilage)

Question 36

What is involved in artificial cartilage implantation?

Answer 36

Grow cartilage in the lab and stitch it with a layer of periosteum covering to cover the defect - this will also stimulate chondrocytes to manufacture articular cartilage

Question 37

What is the appearance of the medial meniscus?

Answer 37

Semicircular

Question 38

What is the appearance of the lateral meniscus?

Answer 38

Circular

Question 39

What are the menisci composed of?

Answer 39

Fibro and chondroblasts in matrix of type I collagen

Question 40

How are the fibres of the menisci arranged?

Answer 40

Circumferential hoop fibres, superficially randomly orientated fibres, radially orientated tie fibres

Question 41

What are the function of the menisci?

Answer 41

Spread the force over the articular cartilage and allow the joint to be more slack allowing for an increase in movement

Question 42

Where does the perimeniscal capillary plexus originate from?

Answer 42

Branches of the inferior medial and lateral geniculate arteries

Question 43

What vessels does the perimeniscal plexus form?

Answer 43

Circumferential vessels and penetrating radial vessels