Mechanical Knee Problems

Question 1

What symptoms does a patient with a mechanical knee problem complain of?

Answer 1

swelling
locking
pain
giving way

Question 2

How does a meniscal lesion present?

Answer 2

pain
effusion
locking/giving way
poorly localised on examination although it can be elicited

Question 3

How is a meniscal injury caused?

Answer 3

twisting injury associated with the foot being planted in studs/a boot. The femur twists over a stationary tibia which can tear or pull the meniscus off the bone.

Question 4

Which meniscus is more frequently torn?

Answer 4

medial

Question 5

In old age, the meniscus may tear horizontally, what is this called?

Answer 5

Cleavage lesion

Question 6

What are the 3 types of meniscal tear?

Answer 6

Bucket handle - vertical split anchored at both ends

Parrot beak - a split off one end of the lateral meniscus

degenerative - tear due to degeneration

Question 7

How does locking occur?

Answer 7

The torn meniscus becomes trapped in the joint and prevents full extension

Question 8

How are peripheral meniscal tears managed?

Answer 8

peripheral tears can be repaiered with sutures and they have blood supply

Question 9

How are tears in the substance of the meniscus repaired?

Answer 9

these are removed as this area of the meniscus has no capacity to regenerate.

Question 10

What technique is used to visualise a torn meniscus once suspicion is aroused?

Answer 10

arthroscopy

Question 11

how do loose bodies occur?

Answer 11

small fragments of cartilage and bone may be sheared off in an injury and become trapped in the joint

Question 12

What are the symptoms of a loose body?

Answer 12

haemarthrosis
pain
swelling

Question 13

How do patients with loose bodies present?

Answer 13

locking, pain, giving way, effusion. can be visible on x-ray

Question 14

How are loose bodies treated?

Answer 14

They are removed via arthroscopy under anaesthetic. Some can occur spontaneously in a condition called osteochondritis dissecans

Question 15

How do cruciate ligament injuries come about?

Answer 15

Commonly via twisting injuries combined with hyperextension, where the foot is anchored in a boot/ski

Question 16

Why are cruciate ligaments not capable of healing if they are torn?

Answer 16

They lose their blood supply

Question 17

How does a cruciate ligament lesion present?

Answer 17

swelling (haemarthrosis)
patient felt a pop
antero-posterior instability and loss of twisting ability.
symptoms when turning or descending stairs common

Question 18

How are cruciate ligament injuries treated?

Answer 18

leave untreated for a while and rehabilitate knee muscles

replace the torn ligament with a synthetic one/graft

Question 19

Why are synthetic ligaments more likely to fail?

Answer 19

They have no stretch receptors so the brain cannot initiate muscle activity to protect the joint

Question 20

What causes patellar dislocation?

Answer 20

malformation of the patella or the lateral femoral condyle. Causes tracking and abrasive moving on the femur and muscle spasm

Question 21

How does it present?

Answer 21

the patella dislocates and the quadriceps fails to extend the leg and the person falls to the ground

Question 22

How is it managed?

Answer 22

minor - surgical splitting of the vastus lateralis tendon on the insertion on the patella allowing it to fit back into normal.

major - if the above is ineffective then plication may be required

Question 23

What is plication?

Answer 23

medial tightening of the vastus medialis muscle