Disorders of the knee

Question 1

What are the common causes of femoral shaft fractures?

Answer 1

• High-velocity trauma e.g. falls from a height, road traffic collision
• High-energy sports (distal fractures)
• Child abuse
• Low velocity injury with predisposing factors e.g. osteoporotic bones

Question 2

What is a tibial plateau fracture?

Answer 2

Fracture affecting the articulating surface of the tibia within the knee commonly affecting the lateral tibial condyle

Question 3

What is the common cause for a tibial plateau fracture?

Answer 3

High-energy injuries

-Axial loading with vargus or valgus angulation of the knee

Question 4

What are the 2 normal causes for a patellar fracture?

Answer 4

• Direct impact injury

- Eccentric contraction of quads (muscle is contracting but joint is extending)

Question 5

What can patients with patellar fracture can’t do?

Answer 5

Straight leg raise

Question 6

What are the treatments for a patellar fracture?

Answer 6

• Reduction and surgical fixation (displaced)

- Crutches (undisplaced, must be protected)

Question 7

What is a patellar dislocation?

Answer 7

Patella completely displaced from normal alignment

Subluxation is partial displacement

Question 8

What is the normal cause of a patellar dislocation?

Answer 8

Twisting injury in slight flexion or direct blow to the knee

Question 9

What is the treatment for a patellar dislocation?

Answer 9

Reduction of patella on an extended knee

• Immobilisation during healing
• Physiotherapy for VMO

Question 10

What is the most common mechanism for a meniscal tear?

Answer 10

Sudden twisting motion of a weight-bearing knee during flexion

Question 11

How may a patients with a meniscal tear present?

Answer 11

• Intermittent pain localised to joint line
• Knee clicking
• Knee catching or locking
• Restricted motion

Question 12

How are acute meniscal tears treated?

Answer 12

Surgically by meniscectomy or meniscal repair

Question 13

What is the common cause for a collateral ligament injury?

Answer 13

Direct contact sports from acute varus or valgus angulation

• Valgus = MCL affected
• Varus = LCL affected

Question 14

What is the unhappy triad?

Answer 14

Injury to the anterior cruciate ligament, medial collateral ligament and medial menisci from strong force applied on lateral knee (blown knee)

Question 15

What is the common mechanism for an ACL injury?

Answer 15

Quick deceleration, hyperextension or rotational injury

-can also occur with large force at the back of knee during flexed

Question 16

What is the common cause for a PCL injury?

Answer 16

Dashboard injury - road traffic collision

Question 17

How are ACL and PCL injuries tested for?

Answer 17

Anterior and posterior drawer test = used for both

Lachman’s test = ACL only

Question 18

What is a knee dislocation?

Answer 18

Displacement of articulating bones in the knee joint

-must at least rupture 3 out 4 ligaments (ACL, PCL, LCL, MCL)

Question 19

What is a knee effusion?

Answer 19

Accumulation of fluid inside the knee joint

Question 20

What is bursitis of the knee?

Answer 20

Inflammation of a bursa in the knee joint (any of the 6)

Question 21

What is a Housemaid’s knee bursitis?

Answer 21

Inflammation of the pre-patellar bursa

Question 22

What is Clergyman’s knee bursitis?

Answer 22

Inflammation of the infrapatellar bursa (superficial is more common than deep)

Question 23

What is a Baker’s cyst?

Answer 23

Bursitis/Inflammation of the semimembranosus bursa

Question 24

What is Osgood-Schlatter’s disease?

Answer 24

Inflammation of the apophysis (site of insertion) of the patellar ligament into tibia

Question 25

What is septic arthritis?

Answer 25

Invasion of the joint space by micro-organisms usually bacteria