Disorders of the Knee

Question 1

Anatomy of the knee

Answer 1

A synovial hinge joint - three compartment

Intra-articular cruciate ligaments and extra-articular collateral ligaments + Intra-articular menisci

Question 2

Function of the Knee

Answer 2

Principally a hinge joint with some limited rotation - minimal inherent bony stability - stability is mainly ligamentous + muscular

Question 3

Cruciate ligaments

Answer 3

ACL –> anteriomedial tibia to posteriolateral on the femur
PCL –> Posteriolateral tibia to anterimedial on the femur
Resist translational forces of the tibia on the femur and rotational forces

Question 4

Collateral ligaments

Answer 4

Protect the knee from Valgus or varus forces
The ‘pes anserinus’ inserts into the top of the MCL joining it to the tendons of the sartorius, gracillus and semitendonosis
The LCL is more flexible than MCL so less vulnerable to injury

Question 5

Knee sprain

Answer 5

Occurs mainly in response to valgus or varus strain
A traumatic effusion of the joint
I - Bruising, II - Partial Rupture, III - Complete Rupture (can be less painful than partial)

Question 6

O’Donoghue’s triad

Answer 6

A common injury among footballers –>
MCL rupture
ACL rupture
Medial mensical tear

Question 7

Examination of a Knee sprain

Answer 7

Look –> bruised, swollen and unable to weight bear
Feel –> effusions and local tenderness
Move –> Pain on movement or on stressing the joint/ligament. There may be instability in the joint as well

Question 8

Investigations for a Knee sprain

Answer 8

X -rays –> will see effusions and increased joint space if the ligaments ruptured
Aspiration –> Clear indicates traumatic synovitis, Blood indicates internal derangement, blood and fat indicates intra-articular fracture

Question 9

Treatment of an acute knee sprain

Answer 9

Grade I or II treat with rehabilitation and RICE (rest, ice, compression, elevation)
Grade III treat with plaster cast for up to 6 weeks and rehabilitation. In rare cases an operation may be required

Question 10

Treatment of a chronic knee sprain

Answer 10

Rehabilitation as with acute but may require an operation to fix chronic instability - EUA and arthroscopy with possible ligament advancement with auto- or allo- grafting

Question 11

Causes of Meniscal Injuries

Answer 11

Acute - twisting or deforming injuries which may cause a ‘snap’ or ‘pop’, may still be able to weight bear but with gradual swelling
Degenerative - from repeated squatting or kneeling leading to pain, discomfort and swelling

Question 12

Symptoms of chronic Meniscal injures (5)

Answer 12

Patient may report locking, giving way, swelling or clicking

There may be general instability or an ‘unsafe’ sensation

Question 13

Examination of Meniscal Injuries

Answer 13

Look - Limping/not weight bearing, swollen/Bruised, poss locked
Feel –> Effusions and tenderness (specific or general)
Move –> painful, restricted, may be locked
Special tests –> +ve Mcmurray’s, Squt/ duck walk test, +ve grind test

Question 14

Investigations in Meniscal injuries

Answer 14

X-rays - effusion and increased joint space if bucket handle tear
MRI - more useful if chronic injury
Aspiration - Blood indicates internal derangement, blood and fat indicates intra-articular fracture

Question 15

Treatment of meniscal injury

Answer 15

Acute - Rehabilitation (RICE) and arthroscopy for menisectomy/repair
Chronic - physiotherapy/arthroscopy and menisectomy

Question 16

ACL injuries

Answer 16

Acute - Twisting injury with pop/snap heard and rapid swelling (1-2hrs) + unable to weight bear
Chronic - Knee feels unstable/unsafe and may give way

Question 17

Examination of acute ACL injuries

Answer 17

Look - limping/not weight bearing, swollen/bruised, poss other injury
Feel - Effusion and tenderness (general or specific)
Move - Painful with RoM limited by pain or effusion, may be unstable

Question 18

Examination of chronic ACL injuries

Answer 18

Look - Quads wasting (VMO)
Feel - Effusion
Move - Lachman, anterior draw and pivot shift positive

Question 19

Investigations for ACL injuries

Answer 19

X-rays - effusion, poss avulsion #, joint laxity or subluxation
MRI - only used for chronic injury
Aspirate - Blood indicates internal derangement, blood and fat indicates intra-articular fracture

Question 20

Treatment for acute ACL injuries

Answer 20

Aspiration or arthroscopy

RICE

Question 21

Treatment for chronic ACL injuries

Answer 21

Physiotherapy and arthroscopy + reconstruction surgery

Use of prosthetics has fallen into disuse, autografts from hamstring or patellar tendons more common

Question 22

Who gets Anterior Knee pain?

Answer 22

Young women
Athletes
Middle aged and older women
Greater risk after trauma or dislocation

Question 23

History in anterior knee pain

Answer 23

Usually retro-patellar pain when squatting, kneeling, going up/down stairs - pain is related to activity
In older patients there is more stiffness on rising which eases with use

Question 24

Examination in Anterior Knee pain

Answer 24

Look - Wasting
Feel - PFJ irritability and tenderness, may have a positive apprehension test
Move - Retro-patellar creptius and possible tight lateral quadriceps expansion

Question 25

Investigations in Anterior Knee pain

Answer 25

X-rays - skyline view to assess patella tilt and any maltracking - Degenerative changes in the PFJ or knee itself MRI is rarely used but is useful to assess cartilage damage

Question 26

Treatment in Anterior Knee pain

Answer 26

Physiotherapy and if needed arthroscopy - assess tracking of the patella, Lateral release or assessment/trimming of the articular cartilage

Question 27

Patella Dislocation

Answer 27

``` Can be acute or chronic: Recurrent - frequent episodes Habitual - dislocates at will Invariable - always dislocates Constant - never in joint ```

Question 28

Investigations in Patella Dislocation

Answer 28

X-rays - AP and Lateral to assess displacement - skyline to look for tilt, maltracking and dislocation/subluxation MRI if query cartilage damage

Question 29

Treatment in Patella Dislocation

Answer 29

Physiotherapy and if needed arthroscopy to assess tracking and perform a lateral release Can perform a realignment procedure using a tibial tubercle transfer or VMO advancement

Question 30

History in Patella Dislocation

Answer 30

Acute - nature of injury, severity of pain, Extent of deformity Chronic - Time since first dislocation, Frequency, nature and cause of dislocation

Question 31

Examination in Patella Dislocation

Answer 31

Look - Deformity if acute or muscle wasting if chronic Feel - Positive apprehension test Move - Tight lateral quadraiceps expansion and retro-patella crepitus

Question 32

VMO

Answer 32

Vastus medialis oblique - important in maintaining proper patella tracking

Question 33

History to take when assessing a sports injury

Answer 33

How did it happen? What were the direction and extent of the forces? Were you able to continue playing? when did symptoms/swelling start? Is there any: instability (linear or rotatory), swelling, locking, pain,

Question 34

Extensor mechanism rupture

Answer 34

Occurs when there is a forced flexion of the leg Osgood-schlatter's disease (10-15yrs) --> Patella tendon rupture (20-40yrs) -->Patella fracture (40-60yrs) --> Quadriceps tendon rupture (60+yrs)

Question 35

Pes Anserine Bursitis

Answer 35

Inferiomedial knee pain -- generally self limiting with exercise and stretching More common in older people and women Sports, diabetes and obesity increase the risk

Question 36

Patellar tendinitis

Answer 36

A common cause of inferior patella pain in people who repeated jump (sports) and is associated with stiff or injured ankles Varies from pain only after activity (stage 1) to complete tear (stage 4)

Question 37

Prepatella burisits

Answer 37

Inflammation of the anterior knee due to inflammation of the bursa due to acute or chronic injury (housemaid's knee) --> painless but tender significant effusion but no restriction of movement (may be discomfort and crepitus). RICE is usually sufficient to treat but aspiration may be needed if severe

Question 38

Osteochondritis dissecans

Answer 38

15-20yrs, a small piece of bone breaks from the condyle | This loose body in the joint leads to pain (after exercise), locking, giving way and swelling

Question 39

Osgood schlatter disease

Answer 39

Occurs in athletics adolescents and presents with pain, swelling and tenderness over the medial tubercle -- may swell Risk factor for tendon rupture but rare

Question 40

Hypermobility

Answer 40

Common and starts in childhood -- family history likely to be positive Recurrent transient knee pain (can also have back pain) Will have hyperflexible joints, stretchy skin and easy to test for

Question 41

Growing pain

Answer 41

Nocturnal pain in children -- most commonly leg pain (can be arms) - rubbing and stretching will ease the pain within a few minutes

Question 42

Chondromalacia patellae

Answer 42

softening of the patella cartilage - commonest in teenage girls. presents as anterior knee pain on using stairs or prolonged sitting. Usually responds to physiotherapy.

Question 43

Patella subluxation

Answer 43

Medial knee pain due to lateral subluxation of the patella. Knee may also give way.

Question 44

Patellar tendonitis

Answer 44

More common in athletic teenage boys - chronic anterior knee pain that worsens after running. Will be tender below the patella on examination.