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Flashcards in Knee orthopaedics and trauma Deck (50):
1

What could predispose to early OA in the knee?

Previous meniscal tears

Ligament injuries (especially ACL deficiency)

Malalignment (genu varum > medial OA, genu valgum > lateral OA)

2

What treatment may benefit a young patient with isolated medial compartment OA?

Osteotomy of the proximal tibia, to shift load onto the lateral compartment

3

In which patients might knee replacement be considered?

Patients with substantial pain and disability where conservative management is no longer effective

4

What kind of knee replacements are there?

Total knee replacement - all three surfaces of the knee replaced

Partial knee replacement - unicompartmental replacement or patellofemoral replacement

5

What is the usual mechanism of injury in a meniscal tear?

Twisting force on a loaded knee

Usually sporting injury in younger patients or atraumatic spontaneous degenerate tears in older patients (over 40)
 

6

How should a suspected meniscal tear be investigated?

MRI

7

What would indicate a meniscal tear on examination of the knee?

Patient reports pain to the medial (majority) or lateral joint line

Effusion develops the next day

Pain on tibial rotation

 Catching sensation or "locking" where they have difficulty straightening the knee with a 15° or so block to full extension

Patients knees may feel about to give way if a loose meniscal fragment is caught in the knee when walking

8

What is the definition of true knee locking?

Mechanical block to full extension caused by a completely torn meniscus flipping over and becoming stuck in the joint line

9

Which kind of meniscal tear will not heal?

Radial

A image thumb
10

What is 'pseudo-locking' in the knee?

Difficulty in straigtening the joint e.g. in arthritis

This is not a full block to extension i.e. this is not a clinical sign of a meniscal tear

11

What other injury occurs in up to 25% of anterior cruciate ligament injuries?

Meniscal tear

12

Which kind of meniscal tear can cause true knee locking?

Bucket handle tear

A image thumb
13

What is the likely cause of a meniscal tear in an older patient?

Degenerative meniscal tear

 

14

How can a degenerative meniscal tear be distinguished from an acute injury?

A degenerative meniscal tear will be Steinmanns negative

Degenerative tears associated with early signs of OA

15

Why do meniscal tears have limited healing potential?

Only has blood supply to the peripheral 1/3

16

What are the only meniscal tears that should be considered for meniscal repair?

Relatively fresh longitudinal tears involving the outer 1/3 of the meniscus in a younger patient

17

What treatment may help the early symtpoms of degenerative meniscal tears?

Steriod injections

18

Which meniscal tears should be referred for arthroscopic meniscectomy?

Radial tears

Chronic tears

Irrepairable tears

Failed meniscal repair

19

What is the principal complaint in ACL rupture?

Rotationary instability with giving way on turning

20

What would indicate an ACL rupture on examination of the knee?

Knee swelling

Excessive anterior translation of the tibia on the anterior drawer test and Lachman test

21

What is the rule of thirds in ACL?


1/3 people compensate and are able to function well 

1/3 can avoid instability by avoiding certain activities or manoevres

1/3 do not compensate and have frequent instability or can’t get back to high impact sport
 

22

What percentage of ACL ruptures end up having reconstruction?

40%

23

What does an ACL reconstruction involve?

 A tendon graft (usually patellar tendon or semitendinosis & gracilis autograft) being passed through tibial and femoral tunnels at the usual location of the ACL in the knee and secured to the bone

Intesive rehab - 3/12 - 1 year

 

24

What is the mechanism of injury in PCL rupture?

Direct blow to anterior tibia (dashboard/motorbike)  

Hyperextension injury
 

25

What are the three grades of knee ligament injury?

Grade 1: sprain - some fibres torn but macrostructure intact
Grade 2: partial tear - some fascicles disrupted
Grade 3: complete tear
 

26

What is the healing prognosis for a medial collateral ligament tear?

Usually heals well even if complete tear

Unless combined with ACL/PCL rupture

27

How are acute MCL tears usually treated?

Hinged knee brace

28

What treatment is avaliable for chronic MCL instability?

MCL tightening

Reconstruction with tendon graft

29

Damage to which nerve is associated with LCL rupture?

Common peroneal nerve

30

What is the usual treatment for LCL rupture?

Early repair or late reconstruction with a tendon graft

31

What are the complications associated with total knee dislocation?

Popliteal artery injury (tear, intimal tera & thrombosis)
 Nerve injury – common peroneal nerve
Compartment syndrome

Tear of all four ligaments

 

32

Why must regular foot examinations be undertaken following a total knee dislocation?

Intimal tears may occur causing thrombosis

Vascular status of foot must be monitored

33

What is the treatment for total knee dislocation?

Emergency reduction

External fixation for stabilisation

Mulitple ligament reconstruction

34

What can cause an osteochondral injury?

 Impaction or shear of the articular surfaces or due to a direct blow

35

What investigations should be done for suspected osteochondral injury?

Xray
MRI

Arthroscopy

36

How should acute injuries with large oestochondral fragments and substantial amounts of bone be managed?

Fixation with pins

37

What management option is availiable If a defect due to osteochondral injury has bare bone at its base?

Microfracture - holes can be drilled into the defect to induce bleeding and encourage formation of fibrocartilidge, scar type hyaline cartilidge, to repair the defect

38

What are the components of the extensor mechanism of the knee?

Tibial tuberosity

Patellar tendon,

Patella

Quadriceps tendon

Quadriceps muscles

39

What are some predisposing factors to development of extensor mechanism rupture?

History of tendonitis

Chronic steroid use or abuse (body builders)

Diabetes

Rheumatoid arthritis

Chronic renal failure

40

What kind of injuries can cause ruputre of the patellar tendon or the quadriceps tendon?

Rapid contractile force which can occur after lifting a heavy weight, after a fall or spontaneously in a severely degenerate tendon

41

Which patients are more likely to have patellar or quadriceps tendon rupture?

Younger - patellar tendon (<40)

Older - quadriceps tendon (>40)

42

Why should steroid injections for tendonitis of extensor mechanism be avoided?

High predisposition to tendon rupture

43

What signs might extensor mechanism rupture show on examination?

Difficulty with straight leg raise test

Palpable gap in extensor mechanism

44

How might extensor mechanism rupture show on Xray?

Low lying patella (quadriceps tendon rupture)

High lying patella (patellar tendon rupture)

45

What is patellofemoral dysfunction?

 It describes disorders of the patellofemoral articulation resulting in anterior knee pain

46

What are some of the symptoms of patellofemoral dysfuncton?

Anterior knee pain - worse going downhill

'Clicking' or grinding sensation at front of knee

Stiffness after prologned sitting causing psuedolocking

47

What are some predisposing factors to patellofemoral dysfunction?

Female

Adolescence

Femoral neck anteversion

Genu valgum

Joint hypermobility

48

What can cause the anterior knee pain in patellofemoral dysfunction?

The pull of the quadriceps muscle tends to pull the patella in a slight lateral direction: in some people, excessive lateral force produces anterior knee pain and the lateral facet of the patella is compressed against the lateral wall of the distal femoral trochlea

Chondromalacia patellae (softening of the hyaline cartilage)

49

What is the treatment for patellofemoral dysfunction?

Physiotherapy

Surgery as a last resort - either releasing a tight lateral retinaculum or if there is a relatively lateralized tibial tubercle, a tibial tubercle transfer to aid patellar trackin

50

Which way does the patella tend to dislocate?

Laterally