Knee

Question 1

what is the main role of the anterior cruciate ligament

Answer 1

limits anterior translation of the tibia (relative to the femur)

Question 2

what is the most common mechanism of ACL tears

Answer 2

athletes who twist their knee whilst in a flexed position and whilst weight bearing

majority occur without contact

Question 3

clinical features of an ACL tear

Answer 3

rapid joint swelling (due to ligament being highly vascularised, hence damage leads to haemoarthrosis)

significant pain

instability

unable to weight bear

Question 4

what are the specific clinical tests to identify an ACL tear

Answer 4

Lachman Test

Anterior draw test

Question 5

describe Lachmans Test

Answer 5

placing the knee in 30 degrees flexion, with one hand stabilising the femur pull the tibia forward to assess the amount of anterior movement of the tibia compared to the femur

Question 6

investigations into ACL tears

Answer 6

plain film radiograph to exclude fracture

gold standard is an MRI scan of the knee

Question 7

management of an ACL tear

Answer 7

as with any acutely swollen knee, the immediate management of a suspected ACL tear is RICE (rest, ice, compression, elevation)

Conservative; rehab and knee splint

surgical; reconstruction of the ACL, or acute surgical repair of the ACL by suturing the two torn ends of the ligament back together

Question 8

classification system used in knee OA

Answer 8

Kellgren and Lawrence system

Grade 0-4 dependent on severity of characteristic OA changes

Question 9

management of knee OA

Answer 9

conservative; weight loss, smoking cessation, exercise, analgesia, physio

surgical; total or partial knee replacement

Question 10

what is patellofemoral OA

Answer 10

osteoarthritis of the articular cartilage along the trochlear groove of the femur and the underside of the patella

common symptom is pain when walking up the stairs (anterior knee)

Question 11

a medial collateral ligament tear occurs after trauma to what part of the knee

Answer 11

lateral side

Question 12

what is the most commonly injured ligament of the knee

Answer 12

medial collateral ligament

Question 13

how are MCL injuries graded

Answer 13

grade I-III

grade III being severe injury with a complete tear of the MCL

Question 14

characteristic feature of an MCL tear

Answer 14

patient reports hearing a ‘pop’ sound followed by immediate medial joint line pain

Question 15

investigations into an MCL tear

Answer 15

X-ray to exclude fracture

gold standard being an MRI

Question 16

management of MCL tear

Answer 16

dependent on the grade of injury

grade I - RICE, analgesia, physio

grade II - analgesia, knee brace, physio

grade III - analgesia, knee brace, crutches, any associated distal avulsion fracture then surgery is required

Question 17

what determines if an MCL tear requires surgery

Answer 17

distal avulsion on MRI

Question 18

what nerve can be damaged in MCL tears

Answer 18

saphenous nerve

Question 19

describe the anatomy of the meniscus of the knee

Answer 19

lateral and medial meniscus - sits on the tibial plateau and acts as shock absorber of the knee joint

the medial meniscus is less circular than the lateral meniscus and is also attached to the MCL whereas the lateral meniscus is not attached to the LCL

Question 20

different types of meniscal tear and which one is most common

Answer 20

longitudinal (Bucket handle) tear - most common

vertical

transverse

degeneration

Question 21

clinical features of a meniscus tear

Answer 21

‘tearing’ sensation in the knee

intense sudden onset pain

locked in flexion and unable to extend

joint effusion

Question 22

investigation into Meniscal tears

Answer 22

x ray to exclude fracture

MRI is gold standard

Question 23

management of meniscal tears

Answer 23

conservative; RICE and analgesia (usually small tears)

surgical; arthroscopic surgery to repair meniscus (larger tears or those remaining symptomatic)

Question 24

mechanism of injury of a patellar fracture

Answer 24

usually either a hard blow to the patella or a strong contraction of the quadriceps muscle

Question 25

what is a bipartite patella

Answer 25

congenital condition whereby there is failure of patella fusion, leaving two separate bone fragments of the patella joined only by cartilaginous tissue

Question 26

management of a patella fracture

Answer 26

conservative; place in cast and ensure early weight bearing (minimally displaced or non-displaced fractures providing extensor mechanism is still intact) surgical; reduction, fixation and restoration of extensor mechanism, ORIF with tension band wiring is the most common method (significant displacement or extensor mechanism is compromised)

Question 27

why are tibial shaft fractures more susceptible to open fractures and compartment syndrome

Answer 27

lack of soft tissue envelope around the bone, particularly anteromedial presence of fascial compartments in the lower leg

Question 28

clinical features of compartment syndrome

Answer 28

pain out of proportion to the injury pain worse on passive stretch of the affected compartments

Question 29

management of tibial shaft fracture

Answer 29

resus and stabilisation realignment under analgesia, following this apply an above knee backslab and elevate limb and closely monitor for signs of compartment syndrome surgical management; IM nailing, ORIF with locking plates (acute compartment syndrome, limb ischaemia or open fracture)

Question 30

common mechanism of a tibial plateau fracture

Answer 30

high energy trauma such as a fall from height, with impaction of the femoral condyle onto the tibial plateau

Question 31

what does fat inside the joint (lipohaemarthrosis) indicate

Answer 31

indicates an intra-articular fracture present e.g. tibial plateau, patella or distal femur

Question 32

management of a tibial plateau fracture

Answer 32

conservative; knee brace, analgesia and physio (uncomplicated fractures) surgical; ORIF to restore joint surface, followed by a knee brace (complicated fractures, open fractures or compartment syndrome)

Question 33

what is the iliotibial band

Answer 33

branch of longitudinal fibres that form the shared aponeurosis of the tensor fasciae latae muscle and the gluteus maximus muscle it extends from the iliac tubercle to the anterolateral tubercle of the tibia

Question 34

what is iliotibial band syndrome

Answer 34

inflammation of the iliotibial band

Question 35

risk factors for iliotibial band syndrome

Answer 35

regular exercise involving repetitive flexion and extension of the knee commonly in runners, weightlifters or cyclists

Question 36

clinical features of iliotibial band syndrome

Answer 36

lateral knee pain exacerbated by exercise

Question 37

specific tests for iliotibial band syndrome

Answer 37

nobles test renne test

Question 38

investigations into iliotibial band syndrome

Answer 38

clinical diagnosis X ray or MRI can be used to exclude other pathologies if history and examination aren't conclusive

Question 39

management of iliotibial band syndrome

Answer 39

conservative; modify activity, analgesia, physio, local steroid injections surgical; involves release of iliotibial band from its attachment at the patella (in functionally limited patients or those who remain symptomatic)