Knee Problems

Question 1

What type of injury causes a meniscal tear?

Answer 1

Classically a twisting force on a loaded knee
e.g. turning in football, squatting
Degenerative tears occur with low energy injuries

Question 2

How does a meniscal tear present?

Answer 2

Localised pain to medial (most common) or lateral joint line
Effusion develops the following day
Catching or locking sensation

Question 3

Which examination findings would be seen in a meniscal tear?

Answer 3

Effusion
Joint line tenderness
Steinman’s test –> pain on tibial rotation localising to the affected compartment

Question 4

Which type of meniscal tear causes locking of the knee and what would be seen on examination?

Answer 4

Bucket handle from longitudinal tear

–> 15 degree block to full extension

Question 5

How is a meniscal tear diagnosed?

Answer 5

MRI

Question 6

What is the initial management of any soft tissue knee injury?

Answer 6

RICE –> Rest, Ice, Compression, Elevate

Question 7

Which meniscal tears can be repaired with surgery and why?

Answer 7

Generally only repaired if fresh, longitudinal tear in outer 1/3 of meniscus in a young patient
–> menisci have limited blood supply so very poor healing potential

Question 8

What is the general management of meniscal tears?

Answer 8

Conservative, usually settles with time
(90% not suitable for surgery)
If no better after 3 months, can consider partial meniscectomy

Question 9

Which type of injury can cause an ACL rupture?

Answer 9

High rotational force, turning upper body laterally on a planted foot e.g. football, rugby, skiing

Question 10

How does an ACL rupture usually present?

Answer 10

Pop usually felt or heard
Haemarthrosis within an hour of injury
Deep pain in knee
Rotational instability –> gives way when turning on a planted foot

Question 11

What would be seen on examination in an ACL rupture?

Answer 11

Swelling

Excessive anterior translation on anterior drawer test + Lachman’s test

Question 12

What is the gold standard for diagnosis of an ACL rupture?

Answer 12

MRI

–> also detects meniscal tears (50% of ACL ruptures also have a meniscal tear

Question 13

What are the management options for ACL rupture?

Answer 13

Conservative –> rehab/physio

Surgery –> ACL reconstruction (only if professional sportsperson or giving way on sedentary activity)

Question 14

What is the prognosis for ACL ruptures managed conservatively?

Answer 14

1/3 compensative very well
1/3 manage with avoiding certain activities
1/3 do poorly

Question 15

What is the most common ligamentous knee injury?

Answer 15

MCL tear

Question 16

What type of injury causes an MCL tear?

Answer 16

Valgus stress injury e.g. rugby tackle from the side

Question 17

What are the clinical features of an MCL tear?

Answer 17

Laxity + pain on valgus stress with tenderness over origin + insertion of MCL

Question 18

What is the management for MCL tears?

Answer 18

Conservative –> forgiving ligament, most heal by themselves

If chronic instability –> MCL tightening or reconstruction

Question 19

What kind of injuries cause a PCL rupture?

Answer 19

Direct blow to anterior tibia with knee flexed e.g. motorcycle crash
Or hyperextension of knee
(usually multiple ligament injuries, rarely occurs in isolation)

Question 20

Which other structures will be injured in a complete knee dislocation?

Answer 20

Rupture of all four ligaments

High incidence of neuromuscular injury

Question 21

How is a complete knee dislocation managed?

Answer 21

Should be reduced as an emergency +/- temporary external fixation
Regular checks on vascular status below knee (thrombosis may occur) –> vascular stenting/bypass
Reperfusion may cause compartment syndrome –> fasciotomies
Usually multiple ligament reconstruction required

Question 22

Which structures make up the extensor mechanism of the knee?

Answer 22

Tibial tuberosity
Patellar tendon
Patella
Quadriceps tendon
Quadriceps

Question 23

What type of injury causes an extensor mechanism rupture and in which group of patients?

Answer 23

Rapid contractile force e.g. lifting or spontaneous if degenerative
Patellar tendon <40s
Quadriceps tendon >40s

Question 24

What are some risk factors for extensor mechanism rupture?

Answer 24

Tendonitis
Chronic steroids e.g. body builders
DM
RA
CKD
Quinolones e.g. ciprofloxacin can cause tendonitis --> rupture

Question 25

What would be found on examination in an extensor mechanism rupture?

Answer 25

Obvious palpable gap

Straight leg raise test +ve

Question 26

What might be seen on xray in an extensor mechanism rupture?

Answer 26

High or low lying patella (depending on which tendon)

Question 27

How is an extensor mechanism rupture diagnose?

Answer 27

Clinical +/- USS confirmation

Question 28

How is an extensor mechanism rupture managed?

Answer 28

Surgical repair –> tendon to tendon repair or reattached of tendon to patella

Question 29

What is patellofemoral dysfunction?

Answer 29

Anterior knee pain due to disorder of patellofemoral articulation

Question 30

What are the clinical features of patellofemoral dysfunction?

Answer 30

Anterior knee pain, worse going downhill
Grinding/clicking sensation
Stiffness after sitting –> pseudo locking (acutely stiffens in flexed position)

Question 31

Which type of injuries cause patellar dislocation?

Answer 31

Direct blow or sudden twist of knee

Question 32

Which way does the patella usually dislocate?

Answer 32

Laterally

Question 33

Which other structures might be injured in a patellar dislocation?

Answer 33

Tear of medial patellofemoral ligament
Osteochondral fracture when medial patella strikes the lateral femoral condyle (small opacification on xray)
Lipohaemarthrosis may occur (characteristic fat pad on xray)