Knee Pathology

Question 1

Name four types of extensor mechanism rupture

Answer 1

• rectus femoris tear
• quadriceps tendon rupture
• patellar fracture
• patellar tendon rupture

Question 2

How does an extensor mechanism rupture usually occur?

Answer 2

Patient falls onto flexed knee with quads contracted

Question 3

What are the risk factors for extensor mechanism rupture?

Answer 3

Previous tendonitis
Steroids
Chronic Renal Failure
Antibiotics

Question 4

How will patients with an extensor mechanism rupture present?

Answer 4

Palpable gap, unable to straight leg raise

Question 5

How is extensor mechanism rupture treated?

Answer 5

Surgical repair/reattachment

X-ray/US

Question 6

What is the function of menisci?

Answer 6

Shock absorbers that act to evenly distribute load from femoral condyles to tibial articular surfaces

Question 7

Describe the difference between the medial and lateral meniscus

Answer 7

Medial - more concave and fixed

Lateral - more mobile

Question 8

Name two types of meniscal tears

Answer 8

Bucket Handle Tear

Degenerative Tear

Question 9

Describe a Bucket Handle Tear

Answer 9

Presents with a locked knee, medical emergency if not repaired may cause problems with femoral condyle
Requires surgery

Question 10

What injury also occurs with a bucket handle tear?

Answer 10

ACL rupture

Question 11

Describe degenerative tears

Answer 11

Oestoarthritis, inflammation

Injection may help

Question 12

Why does the meniscus have limited healing potential?

Answer 12

Peripheral blood supply

Question 13

When would a arthroscopic meniscectomy be indicated?

Answer 13

Mechanical symptoms
Irrepairable tears
Failed meniscal repair

Question 14

Describe an MCL tear

Answer 14

MCL resists valgus stress

Rupture may lead to values instability but usually heals completely

Question 15

Describe the treatment of an MCL tear

Answer 15

Hinged knee brace

Early motion physiotherapy

Question 16

Describe a ACL tear

Answer 16

ACL resits anterior subluxation and internal rotation

Rupture will lead to rotatory instability

Question 17

What is the rule of 1/3 in ACL tears?

Answer 17

1/3 compensate
1/3 avoid instability by avoiding certain activities
1/3 do not compensate and have frequent instability

Question 18

Name two types of ligament reconstruction

Answer 18

Autograft - hamstring/patellar tendon

Allograft - achilles

Question 19

What is the difference between tendons and ligaments?

Answer 19

Tendons lack nerves and do not treat pain or prevent arthritis

Question 20

What causes PCL rupture?

Answer 20

Direct impact, recurrent hyperextension or instability going down stairs
Blow to anterior tibia presents with popliteal knee pain and bruising

Question 21

What can LCL tears cause?

Answer 21

Common fibular nerve palsy

Question 22

What will knee dislocation cause?

Answer 22

Rupture of all four ligaments
Artery injury
Nerve injury
Compartment syndrome

Question 23

How is knee dislocation treated?

Answer 23

Emergency reduction, multi-ligament reconstruction may need temporary stabilisation by external fixation

Question 24

What are the risk factors for patellar dislocation?

Answer 24

Ligamentous laxity 
Female
Shallow trochlear groove 
genu valgum 
high riding patella

Question 25

What injury can occur at the same time as patellar dislocation?

Answer 25

Medial patellofemoral ligament tear and osteochondral fracture