soft tissue knee injuries lecture

Question 1

Which menisci is under greater stress and why?

Answer 1

Medial meniscus under greater amount of shear stress - Due to shape and soft tissues, knee pivots on medial compartment through flexion and extension.

Question 2

What is the function of the MCL ?

Answer 2

Resists valgus stress

Question 3

What is the function of LCL?

Answer 3

Resists varus stress

Question 4

Whta is the function of the ACL?

Answer 4

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

Question 5

What is the function of the PCL?

Answer 5

Resists posterior subluxation of the tibia ie anterior subluxation of the femur and hyperextension of the knee

Question 6

What area resists external rotation of the tibia during flexion and what are the main structures which form this area?

Answer 6

The posterolateral corner – the PCL and LCL with popliteus and other smaller ligaments resist external rotation of the tibia in flexion

Question 7

What may MCL rupture lead too?

Answer 7

vlagus instability

Question 8

What may posterolateral corner rupture lead too?

Answer 8

Recurrent hyperextension or instability descending stairs

Question 9

What vwould be seen if multiple ligaments are ruptured?

Answer 9

gross instability

Question 10

Why can a longitudinal cartilage tear be repaired but a bucket handle tear cannot ?

Answer 10

Because the peripheral 1/3rd of cartilage has a blood supply hence longitudinal tears can be repaired and bucket handle ones cannot

Question 11

Which menisci is more commonly torn?

Answer 11

the medial (10X’s more likely)

Question 12

What do people who rupture their ACL commonly also injure?

Answer 12

approx 50% also have menisci tears

Question 13

What is the common mechanism for meniscal injury?

Answer 13

Usually sporting injury in younger patients or getting up from squatting position in younger patients

Question 14

In older patients (over 40) what type of meniscal injury are they also at risk of ?

Answer 14

Atraumatic spontaneous degenerate tears

Question 15

What test is done to confirm the diagnosis of a meniscal injury?

Answer 15

MRI

Question 16

Will radial catilage tears repair ?

Answer 16

No

Question 17

In an acute peripheral cartilage tear in a younger patient what could be considered ?

Answer 17

Arthroscopic repair - up to 40% failure rate

Question 18

For a meniscal tear which is irreparable or a failed meniscal repair - in which the patient is experiencing painful catching or locking, what could be considered to treat this ?

Answer 18

Arthroscopic menisectomy for mechanical symptoms

Question 19

What does an acute locked knee signify ?

Answer 19

A displaced bucket handle meniscal tear -Patient will have 15 degree springy block to extension

Question 20

Describe the classification of grading knee ligament injuries

Answer 20

• Grade 1 – sprain – tear some fibres but macroscopic structure intact
• Grade 2 – partial tear - some fascicles disrupted
• Grade 3 – complete tear

Question 21

Which ligament in the knee has a good blood suplpy and hence even when ruputured rarley requires surgery?

Answer 21

MCL usually heals well even if complete tear unless combined with ACL or PCL rupture

Question 22

What is the usual treatment for an injury to the MCL?

Answer 22

• Brace
• early motion
• physio

Question 23

When is the ACL usually injured ?

Answer 23

Usually sports injury – football, rugby, skiing

Question 24

What is the treatment for an ACL rupture?

Answer 24

Usually reconstruction using:

• Autograft – Patellar tendon or hamstrings
• Allograft – Achilles
• (synthetic graft)

Physio can also stabilise the knee

Question 25

What is the rule of 1/3rds in ACL rupture?

Answer 25

n1/3 compensate and are able to function well n 1/3 can avoid instability by avoiding certain activities n 1/3 do not compensate and have frequent instability or can’t get back to high impact sport

Question 26

What are the reasons for carrying out an ACL reconstruction ?

Answer 26

* Rotatory instability not responding to physio * Protect meniscal repair * Rapid return to professional sport or high demand job * Adolescent or young adult - ?more reliable option * Keen on high impact sport * As part of multiligament reconstruction

Question 27

What is the duration of rehab following an ACL reconstruction ?

Answer 27

3/12 to 1 year

Question 28

After 10 years following an ACL reconstruction what do patients usually have on radiograph?

Answer 28

Arthritic changes

Question 30

Injury to LCL causes what?

Answer 30

varus instability and hyperextension

Question 31

In LCL injury what nerve is commonly damaged ?

Answer 31

High incidence common peroneal nerve palsy

Question 32

What does injury to LCL commonly occur with?

Answer 32

PCL or ACL injury

Question 33

What is the treatment for LCL rupture ?

Answer 33

* Complete rupture needs urgent repair if early (within 2-3 wks) * Later à reconstruction (hamstring or other tendon)

Question 34

What is the common mechanism for injury to the PCL ?

Answer 34

Direct blow to anterior tibia, (Dashboard / Motorbike) or hyperextension injury

Question 35

Is it common to have an isolated rupture to the PCL ?

Answer 35

No - usually occurs with other injury

Question 36

If the PCL rupture is isolated what is usually the treatment plan ? If PCL is involved in mutliligamenty injury what is the treatmeant ?

Answer 36

if isolated - often doesn't require reconstruction so physio If mutliligament - requires reconstruction followed by physio

Question 37

Knee dislocation is a serious high energy injury with high incidence complications, what are some of these complications ?

Answer 37

* Popliteal artery injury (tear, intimal tera & thrombosis) * Nerve injury – common peroneal nerve * Compartment syndrome * Multiligament injury

Question 38

What is the treatment for knee dislocation ?

Answer 38

emergency reduction, recheck neurovascular status. if concerns with vascular status may need vascular surgery

Question 39

What may need to be done to stablise the knee after dislocation ?

Answer 39

May need ex fix for temporary stabilisation

Question 40

What ligament holds the patella in place ?

Answer 40

MPFL (Medial patellofemoral ligament)

Question 41

What is the common mechanism for patellar dislocations?

Answer 41

Rapid turn or direct blow

Question 42

What factors predispose patients to soft tissue knee injuries?

Answer 42

* Previous tendonitis * Steroids * Chronic renal failure, Ciprofloxacin

Question 43

Give an overview of the cmoon soft tissue knee injuries and their mechanisms for injury

Answer 43

* Valgus à MCL * twisting à ACL or meniscal injury * varus à LCL * dashboard / hyperextension à PCL * getting up from squatting à meniscal tear

Question 44

Football injury, twist, pop, haemarthrosis, generalised pain, pain settles after a few days, rotatory instability. What inury is this a classic histroy of ?

Answer 44

ACL rupture

Question 45

Getting up from squatting, sudden sharp pain medial joint line, effusion, recurrent medial pain & catching +/- locking. What injury is this a classic history of?

Answer 45

Meniscal tear