Knee fracture (patella, tibeal plateau)

Question 1

What is the Lachman’s test for?

Answer 1

ACL tear only

Question 2

What is the McMurray’s test for?

Answer 2

Meniscal tears

Question 3

What are the two types of patella fracture?

Answer 3

1. Comminuted
2. Avulsion or transverse

Question 4

How is a comminuted patella fracture acquired?

Answer 4

Direct blow usually against the dashboard of a car. Stellate fracture shown below.

Question 5

What is the management of comminuted patella fracture?

Answer 5

Surgery - excision of patella should be avoided

Rehabilitation with early movement and physiotherapy to regain quadriceps power.

Question 6

What is the mechanism of injury in avulsion/transverse fractures of the patella?

Answer 6

Violent contraction of the quadriceps against resistance

Question 7

What is the management of avulsion/transverse fractures of the patella?

Answer 7

1. Open reduction and figure of eight wire
2. Early mobilisation - to avoid stiffness and muscle atrophy

Question 8

What is a complication of patella fracture?

Answer 8

Osteoarthritis of the patellofemoral compartment

Question 9

What is the mechanism of injury of intercondylar tibia fractures?

Answer 9

Avulsion injuries linked to the ACL

Question 10

What is the mechanism of injury of the tibial plateau?

Answer 10

Forcible varus or valgus strain e.g. being struck by a car bumper

The knee will fill with blood and may feel unstable on lateral and medial stressing.

Question 11

Which part of the tibial plateau is usually affected in fractures?

Answer 11

Lateral tibial plateau

Question 12

What is the management of tibial plateau fractures

Answer 12

If stable: conservative management in a brace to encourage movement.

If displaced:

1. Open elevation of the joint surface with a bone graft to fill the underlying defect
2. Plate and screws
3. Early mobilisation

Severe fractures on both sides of the knee:

• Circular frames (external fixators) or ‘locking’ plates

Question 13

When are fractures of the tibial shaft and fibula most common ?

Answer 13

Often follow road traffic and sportic events

May be open fractures

Question 14

Which position do tibial fractures tend to displace into?

Answer 14

Varus

Question 15

What is the management of tibial shaft and fibula fractures?

Answer 15

• Wound management - debridement, may need to be left open
• Plaster-cast fixation - if stable
• Internal fixation - if unstable
• External frame fixation - pins above and below the fracture, done if there is too much contamination for internal fixation
• Close-fitting cast-brace - Sarmiento, allows movement of the knee but needs expertise. Weight bearing permitted after 3 weeks

Question 16

How long does healing of tibial fractures take?

Answer 16

• Usually immobilised for 3 months
• May take 5 or more months for union
• Weight bearing can begin if internal fixation is used otherwise wait 6 weeks.

Question 17

What is the significance of isolated fractures of fibular shaft?

Answer 17

Of little significance, can be treated with supportive dressing or plaster-cast until painless.

Question 18

Name 3 common complications of lower limb fractures.

Answer 18

• Non union
• Ischaemia of deep muscles of calf due to compartment syndrome. This may cause flexion contractures of the toes.
• Stiffness of knee, ankle and foot