Knee Theory (Manual)

Question 1

List the feature of late stage knee OA.

Answer 1

i) osteophytes
ii_ subchondral cysts
iii) meniscal maceration
iv) subchondral sclerosis

Question 2

List the functions of knee menisci.

Answer 2

i) shock absorption
ii) joint congruity
iii) load distribution

Question 3

Outline pathological mensical extrusion.

Answer 3

i) extrudes > 3mm any direction
ii) most commonly medially from tibial plateau
iii) can be caused by MCL disruption or OA (causitve or a result of extrusion)

Renders menisci useless

Question 4

Which type of meniscus tear is most associated with tibiofemoral degeneration/early OA?

Answer 4

medial meniscus posterior horn radial horn tears

Question 5

Describe how alignment/biomechanics contribute to medial compartment OA.

Answer 5

Increased perpendicular distance between GRF and center of rotation creates a knee adduction moment. This loads the medial compartment and contributes to OA.

Ipsi hip ABD weakness causes COM to shift away from stance leg and increase KAM as well.

Patellar maltracking can contribute to joint stresses as well.

Question 6

List the criteria to rule in knee OA for given patient:

Answer 6

Knee pain with at least 3 of the following:

1. Age > 50
2. Stiffness <30min
3. Bony Enlargement
4. Palpable tenderness with no warmth
5. Crepitus
6. Bony tenderness

Question 7

To confirm OA on imaging, what special features are needed?

Answer 7

1. WBing views

2. PF views

Question 8

Outline some medical management recommendations regarding knee OA.

Answer 8

1. PRP is only beneficial for short term pain relief post TKA
2. Do not use glucosamine chondroitin
3. Corticosteroid injections can offer short term relief
4. Hyaluronic acid injections can offer relief possibly even past 12 weeks, may have better safety long term than cortisone
5. Topical NSAIDs are best to limit other side effects

Question 9

Describe the etiology of ITBFS.

Answer 9

At 30 deg of knee flexion, IT band moves from anterior to posterior position and crosses over the femoral condyle. This friction can cause inflammation/pain of the tissue itself as well as a fat tissue underneath.

Question 10

List some risk factors for ITBS.

Answer 10

i) tibial rotation
ii) hip IR
iii) reduced DF
iv) weak hip ER
v) improper footwear
vi) genu varum
vii) recent increase in training

Question 11

List the special test for ITBS.

Answer 11

i) Renne’s
ii) Noble’s
iii) Can do Ober’s

Question 12

Outline the main treatment components for ITBS.

Answer 12

i) Education/modification of training regime or footwear
ii) hip Abductor strengthening
iii) address tight TFL and glute max
iv) hip ER strength
v) functional motor control exercises
vi) deep frictions

Question 13

Outline risk factors for development of patellar tendinopathy.

Answer 13

i) Jumping sport/ability to jump higher
ii) reduced DF
iii) reduced LE posterior chain flexibility
iv) hard playing surface (ex. cement).
v) weak hip ABD and ER
Note: inferior pole impingement of tendon on MRI

Question 14

Outline the testing/diagnostic process for patellar tendinopathy.

Answer 14

i) palpation
ii) functional testing (jump, lunge, SL squat etc.)
iii) SL squat on a 25 deg slope
iv) VISA-P special outcome measure

Question 15

Outline the main treatment components for patellar tendinopathy.

Answer 15

i) addressing ankle mobility deficits
ii) addressing hip rotational( ++ evidence for rotational) and ABD deficits
iii) managing tendon load (therapeutic load) w/ exercises and reducing other activities that play excessive loading
iv) BEGIN with isometric 70-80% MVC at 60 deg flexion 45s for 5 reps
v) eccentrics for the quads and stretching for quads, progress to plyometrics etc.

Mild evidence for shockwave.

Note: avoid deep frictions, no effect

Question 16

List some instrinsic factors that place one at risk for PFPS.

Answer 16

i) large Q angle
ii) increased navicular drop
iii) female
iv) weak quads, secondarily hams\
v) hip IR and reduced knee flex on landing from jump
vi) weak hip ABD and ER
vii) tight quads and gastrocs

Question 17

Explain the relationship between the two bundles of the ACL.

Answer 17

The posterolateral bundle is more taut in extension, the anteriomedial bundle is more taut in flexion limiting the anterior tibial load.

Question 18

List the early signs of an ACL injury

Answer 18

i) immediate intense pain and swelling (hemoarthorisis)
ii) may have a pop
iii) feeling of instability/giving out on WBing

Question 19

List the ACL tests in order of validity.

Answer 19

i) Lachman’s
ii) Lever’s sign
ii) Pivot Shift
iii) Anterior Drawer

Question 20

Describe the secondary injuries that commonly occur with an ACL injury.

Answer 20

i) medial meniscus tear/MCL
ii) lateral tibial plateau fracture
iii) posterolateral corner (biceps fem, area of capsule, popliteus, LCL)

Question 21

Describe differential diagnoses with similar early signs of ACL rupture/injury?

Answer 21

i) patellar dislocation

ii) osteochondral fracture

Question 22

Describe how the different bundles of PCL function.

Answer 22

The anteromedial bundle is taut in mid flexion and internal rotation. The posteromedial bundle is taut in extension and full flexion. Together they limit posterior tibial translation, IR and provide posterolateral stability.

Question 23

Explain the MOI for a PCL injury.

Answer 23

i) dashboard injury
ii) falling hard on tib tuberosity (hyperflexion)
iii) hyperextension

Most often (95%) with other ligament tears

Question 24

List the tests for a suspected PCL injury.

Answer 24

i) POsterior sag
ii) active quadriceps test
iii) Posterior drawer
iv) supine internal rotation test (measures tib tube excursion in some flexion to diagnose PCL tears, highly valid)

Question 25

Describe the protocol in an isolated Gr. III PCL tear.

Answer 25

i) immobilized in extension for 2-4 weeks
ii) progress WBing
iii) add strength, proprio etc. in CKC

RTS in 3 mo

Question 26

Describe the protocol in a PCL reconstruction.

Answer 26

Note rehab is 6mo - 12mo, twice the healing time as ACL. Non WBing for 6 weeks.

Goals:
i_ reduce varus
ii_ reduce ER stresses
iii_ reduce posterior tibial translation

Question 27

Describe how patellar dislocation/subluxation typically occurs.

Answer 27

i) Foot fixed and femur IR over fixed tibial, compromising MPFL and resulting in lateral displacement.
iii) knee valgus in mild-mod flexion

Question 28

What are important factors to rule out in suspected patellar dislocation?

Answer 28

i) osteochondral lesions

ii) loose bodies

Question 29

What risk factors are associated with recurrent patellar dislocations?

Answer 29

i) trochlear dysplasia
ii) patella alta
iii) female
iv) < 18 yo first time
v) high tib tuberosity to trochlear groove distance

Question 30

When is surgery for patellar dislocation most recommended?

Answer 30

i) chronic/recurrent - conservative measures fail
ii) children who want to return to sport/young athletes
iii) Individuals with severial risk factors (ie esp trochlear dysplasia)

Question 31

Describe the separate components and functions of the MCL.

Answer 31

i) superficial (sMCL) functional limit primary valgus stress
ii) deep (dMCL) function to limit anteromedial rotation
iii) posterior oblique ligament blends with both

Note: the pes anserine blends with MCL distally to resist tibial ER in knee ext. VMO also may contribute

Question 32

Describe the MOI for an MCL tear.

Answer 32

i) external force causing valgus stress with foot planted

ii) valgus stress w/ ER of tibia (ie pivot)

Question 33

Outline ligament testing for a suspected MCL tear.

Answer 33

i) Valgus stress test (0 and 30 deg)
ii) Swain rotatory stability test (tibial ER and valgus stress at 90 deg and 30 deg flex)

I - no instability
II - instability 5-15 deg (flex > ext)
III - instability > 15 deg

Question 34

Describe an important early intervention in a suspect Gr. II MCL tear.

Answer 34

i) hinged brace limiting valgus and rotation will reduce fibrosis and changes of recurrence or degenerative changes down the line.

Question 35

Outline the protocol following MCP reconstruction.

Answer 35

i) brace 6 weeks, non WBing
ii) first 2 weeks limit flexion to 90
iii) goal for 130 deg flexion at 6 weeks
iv) Min 20 weeks to return to sport/activity.

Question 36

Describe the MOI of a meniscal tear.

Answer 36

Coupling of compression and transverse rotationw hen the knee if moving from flexion to extension. Med meniscus 3x more often than lateral.

Question 37

List the key criteria that can be used to rule in a mensical tear

Answer 37

i) history of “catch” or lock (> 3)
ii) twisting MOI
iii) audible click on McMurrays (>3)
iv) jt line tenderness (Meniscal composite needs >3)
v) pain on max flexion (MC of >3 or more)
vi_ pain on hyperextension (MC >3)
vii) delayed onset of effusion

Question 38

Describe the MOI of an osteochondral lesion in the knee.

Answer 38

i) Pivot shift will affect lat fem condyle, posterior lateral tibial plateau, posterior medial fem condyle
ii) hypertextension affect ACL and PCL will injury more anteriorly
iii) patellar dislocaton

Question 39

List in order the most common areas for ostechondral lesions of the knee

Answer 39

Med femoral condyle, patellar, lateral condyle, trochlear groove

Question 40

List in order the injuries most commonly associated with osteochondral injuries.

Answer 40

Meniscal tear, ACL, then collateral ligament tears

Question 41

Describe the presentation of osteochondral lesions.

Answer 41

Insidious onset (revised to history of trauma,, intermittent pain and swelling, may have catching and lockng, pain with repetitive movement/impact. May have hemoarthrosis if traumatic.