Week 6 - G - Regional Adult Trauma (6) - Knee&Patellar dislocations, Tibial fractures

Question 1

True knee dislocations are uncommon but can occur in high energy injuries or with severe hyperextension and/or rotational forces with a sporting injury. What ligament is torn in a knee dislocation?

Answer 1

Usually multiple ligaments are torn in a knee dislocation

Question 2

What is a true knee dislocation?

Answer 2

It is where the bones of the tibia and fibula are moved in relevance to the femur

Question 3

Obvious knee dislocations should be reduced urgently What should be checked urgently in a knee dislocation?

Answer 3

Check the neurovascular status

Question 4

Patellar dislocations are relatively common. Is it more common to have a medial or lateral patellar dislocation?

Answer 4

It is more common to have a lateral patellar dislocation - virtually all are lateral

Question 5

How do patellar dislocations tend to occur?

Answer 5

Tend to occur due to a direct blow to the kneecap or when the quadriceps tendon is contracted and the knee rotates

Question 6

What is the groove between the condyles of the femur where the patella sits?

Answer 6

Sits in the trochlear groove

Question 7

Patellar dislocations and subluxations are more common in adolescents, What are some predisposing risk factors to patellar dislocations and sublaxations?

Answer 7

Being female

Generalised ligamentous laxity

Muscular imbalnce

Valgus alignement of the knees

Shallow trochlear groove and

rotational malalignment

Question 8

What is the main sign of patella femoral dysfunction?

Answer 8

There is knee pin with the leg being unable to flex

Question 9

What percentage of patients will experience a further patellar dislocation after their first patellar discloation? What percentage of these patients will go on to have multiple recurrent dislocations?

Answer 9

Around 10% of all first time patellar dislocation patients will experience a further dislocation and

50% of those will have multiple recurrent dislocations

There 5% of patients will have multiple recurrent dislocations after their first patellar dislocation

Question 10

What is the proximal part of the tibia known as?

Answer 10

The tibial plateua

Question 11

Which bone of the leg does not take part in the knee joint?

Answer 11

The fibula

Question 12

Tibial plateau fractures can be either high energy injuries in the younger patient or low energy in osteoporotic bone. What type of fracture is a tibial plateua fracutre?

Answer 12

It is an intraarticular fracture

Question 13

What is the usual treatment of a tibial plateau fracture?

Answer 13

Intraarticular fracture usually treated using open reduction and internal fixation (ORIF) with plates and screws

Question 14

Despite efforts to restore the articular surface, results of surgery are often disappointing and patients often require what as treatment?

Answer 14

Often require total knee replacement as treatment

Question 15

What are the five types of fracture patterns?

Answer 15

Transverse fractures - occur due to bending

Oblique fractures - occur due to shearing (direct blow, decelerating)

Spiral fractures - due to torsional force

Comminuted - 3 or more segments -very unstable

Segmental - bone is fractured in 2 segments - v unstable

Question 16

Tibial shaft fractures usually occur with indirect force and either * bending or * rotational energy , * compressive force from deceleration or, * a combination of these forces or from high energy injuries What pattern of fracture does each cause?

Answer 16

Bending - transverse fracture

Rotation energy - spiral fracture

Compressive force from deceleration - oblique fracture

Combination of these force or from high enrgy injuries - comminuted fracture

Question 17

Up to 50% displacement and 5° of angulation in any plane for a tibial fracture requires what treatment?

Answer 17

Up to 50% displacement and 5degrees angulation is conservative treatment in an above knee cast

Question 18

Why are open fractures not uncommon in tibial shaft fractures?

Answer 18

The tibial shaft is subcutaneous - very close to the skin

Question 19

How are open tibial fractures treated?

Answer 19

Internal or external fixation provided a thorough debridement has been performed

Question 20

Any internal rotation of the distal fragment is poorly tolerated in a tibial fracture What is the main method of treating a tibial shaft fracture if greater than 50% displacement or 5degrees angulation?

Answer 20

Internal fixation using an intramedullary nail

Question 21

The intramedullary nail is inserted behind the patellar tendon and therefore what do 25% of patients complain of which is important to discuss?

Answer 21

25% of patinets suffer significant anterior knee pain (remember this pain aka patellofemoral pain typically occurs in young active females - mainstay of treatment is physiotherapy)

Question 22

External fixation is favoured by some for tibial shaft fractures however what are some cons?

Answer 22

Pin site infection or loosening may occur

Question 23

As tibial fractures are a main cause of compartment syndrome in the leg What is the treatment? How many compartments are in the leg?

Answer 23

Fasciotomy (4 compartments in the lower leg)

Question 24

Just like distal femur fractures, distal tibial fractures can be extra or intra articular What is the treatment for extra-articular fractures in an acceptable position?

Answer 24

This would be conservative treatment

Question 25

What is an intra-articular distal tibia fracture also known as?

Answer 25

Pilon fracture

Question 26

What is the gernal treatment of pilon fractures?

Answer 26

If swelling present - then external fixation until swelling goes down and then ORIF

Question 27

If the cause of the distal tibia fracture is post-traumatic OA, what is the treatment?

Answer 27

Usually arthrodesis

Question 28

An intrarticular tibial fracture is known as a pilon fracture as pilon is french for pestle (mortar and pestle) The talus (pestle) drives into the distal tibia (mortar), how does this occur usually?

Answer 28

Usually high energy fractures due to a fall from a height or deceleration

Question 29

Which bones form the ankle joint?

Answer 29

The tibia, fibula and the talus form the joint