Knee Flashcards
Which radiograph view is best for assessing patellar position
axial oblique- “sunrise” or “skyline”
What tilt of patella may be associated with subluxation?
lateral tilt (greater than 16 degrees)
What is typical tilt of patella
6 degrees medial
How does axis of knee shift in SLS?
Shifts medially
Shape of menisci
lateral: O
Medial: C
Which meniscus is more mobile
lateral
What muscle attaches to medial meniscus?
semimembranosis
What muscle attaches to lateral meniscus
popliteus
LCL function
limit varus and tibial ER
Which position isolates LCL from other structures for testing?
flexion
Which position is best for testing MCL
flexion
Which two ligaments contribute most to valgus prevention
MCL, PCL
Does MCL have good blood flow
Yes
Which is more firmly attached to capsule, MCL or LCL
MCL
Which bundle of ACL is larger?
posterolateral
Which portion of ACL is tested more in flexion?
anteromedial
At which position is posterolateral bundle of ACL greatest restraint to translation
Less than 20 degrees of flexion
If anteromedial bundle torn, and posterolateral bundle intact, what will result of anterior drawer be?
positive- anteromedial provides more restraint in increased flexion
Which tibial rotation increases tension on ACL
medial/internal (specifically anteromedial bundle)
Which bundle of PCL is larger?
anterolateral (95% of size)
In which position is anterolateral bundle of PCL more taut
flexion
In which position is posteromedial bundle of PCL more taut?
extension
In which position does PCL provide more support against posteriorly driven forces?
flexion (anterolateral bundle is larger)
Which ROM will largest increase in posterior translation occur in PCL tear?
70-90 degrees of flexion- due to laxity of secondary supports
Can muscles generate and/or resist varus/valgus forces?
Yes
In which ROM of weight bearing activities are posterior shear forces greatest?
83-105
In nonweight bearing extension, which ROM is a posterior force at knee present?
between 60 and 100 degrees of flexion
In nonweight bearing extension, at which ROM is an anterior force present?
last 40 degrees, peaking in last 10
As knee flexion increases, what happens to patellar contact with femur?
increases, loading of odd and lateral facets occurs beyond 90 degrees flexion
In which knee position would compressive forces from quadriceps be higher on the patella?
flexion more than extension
Why may SLR be appropriate with patellar arthritis or patellofemoral contact pain?
Decreased compressive forces in extension and more favorable moment arm
Patellofemoral compression forces during walking, jogging, and sit to stand?
walking: 50%
jogging: 3-4x
sit to stand: 6.7x
Which facet of patella bears greatest load at patella up 70 degrees of flexion
medial
Normal Q angles
10-15 for men, 15-20 for women
ROMs to avoid to limit patellofemoral stress (OKC and CKC)
OKC: last 30 degrees of extension
CKC: beyond 90
Ottowa knee (5 items)
Age greater than 55 Isolated patellar tenderness Tenderness of fibular head Inability to flex beyond 90 Inability to bear weight immediately and in ED
Risk factors for SCFE
Overweight/very tall or very thin prepubescent boys (8-17)
anterior knee/thigh pain with negative knee exam
Knee pain reproduced with FABER may be caused by?
SCFE
What hip ROMs may be present with SCFE
lack of IR with excessive ER
What is Legg-Calve-Perthes?
AVN of femoral head
pediatric
What is WOMAC used for?
OA of knee
What is benefit of Knee injury and Osteoarthritis Outcome score (KOOS) over WOMAC?
Designed to be more responsive to higher activity levels
What patient population is the Lysholm Knee Score designed for?
Ligamentous and meniscal injuries
Does quadriceps recruitment suffer in conditions of effusion?
Not supported by evidence.
Saline injections diminish function, but not demonstrated in situ
If valgus stress test in full extension has <5 mm laxity, which additional ligaments other than MCL may be involved?
ACL (more likely) and PCL
What is most specific position to test MCL?
30 degrees of flexion
Which ACL bundle is tested primarily in anterior drawer?
anteromedial
If anterior drawer is more pronounced with tibial ER, what else may be involved?
MCL, medial capsule, posterior oblique ligament
Sensitivity and specificity of anterior drawer?
Poor in acute, good in chronic
Sensitivity and specificity of Lachman
85% and 94%
Which bundle of the ACL is tested primarily with Lachman test?
Posterolateral
Sn and Sp of posterior drawer?
90% and 99%
Posterior sag sign Sn and Sp
795, 100%
Quadriceps activating test use and Sn/Sp
PCL tear. 97%/100%
Tests used to identify posterolateral corner compromise?
posterolateral drawer test, proner ER, reverse pivot shift, ER recurvatum test
What structures make up the posterolateral corner?
Arcuate ligament, LCL, popliteal tendon, lateral gastroc
If posterior translation is slightly increased at 30 degrees, but normal at 90 degrees, what injury may have occured?
posterolateral injury
If increased ER of tibia noted at 30 degrees but not 90, what may be indicated?
posterolateral corner injury
If increased ER of tibia noted at 30 and 90 degrees, what may be indicated?
posterolateral corner and PCL injury
What is stronger for McMurray test, Sn or Sp
Specificity, a negative test does not rule out condition
If rotation is painful at knee, what motions can indicated ligament vs meniscus?
Worse with distraction=ligament
Worse with compression=meniscus
Is joint line tenderness for meniscal damage more sensitive or specific?
Sensitive
Which degree of knee bending is better for Thessaly test, 5 degrees or 20 degrees?
20 degrees is more Sn, Sp, and positive predictive value
Meniscal Pathology Composite score (5 items)
History of catching/locking Pain with forced hyperextension joint line tenderness Positive McMurray pain with maximal flexion
If all 5: 92.3% chance of meniscus tear
3/5: 75%
Normal patellar excursion
25-50% of width.
Laxity known as sage sign
Strongest tests for PFPS
pain with isometric quadriceps contraction
pain with squatting
pain with palpation
2/3= +LR 4.0
Which hop tests had best correlation with self reported knee function?
cross over and 6m hop
Loose packed position of knee
25-30 degrees of flexion
What degree of quadriceps weakness should NMES be considered at?
15% deficit or greater
Are eccentric exercises more beneficial than standard exercises for patellar tendonitis?
No, there is benefit to using them as part of plan, but no evidence of superiority
Return to sport Quad-hamstring ratio goals
> 66% male, >75% female
Does taping help with patellofemoral pain due to knee OA
Yes, but questionable evidence if any repositioning occurs
Are unloading braces beneficial for knee OA
They can be.
Ineffective with obese, and only for unicompartmental degeneration
Effect of bracing post ACL reconstruction
No effect on functional testing or laxity.
Decreased quadriceps strength if used for 1-2 years
Bracing following PCL reconstruction
Not typically used, but if used d/c’d within 4 weeks.
What criteria (4) are recommended for rehabilitation, not surgery following ACL tear
no more than 1 episode of giving way
>80% on hop test
KOS ADL >80%
global rating score >60%
What has increased risk following patellar graft for ACL
anterior knee pain, mild increase in patellar fx in rehab
What has increased risk following hamstring graft?
hamstring strain. (no strength deficits)
What is ideal time frame for ACL reconstruction?
time not important, but acute inflammation should not be present
At which ROM is strain greatest on ACL?
last 30 degrees of OKC knee extension
What muscle group should be focus of ACL rehab?
quadriceps (hamstrings recover strength without targeted therapy, even if used for graft)
ROM restrictions with ACL/meniscus repair?
weight bearing flexion past 45 degrees
If chondroplasty performed with ACL tear, what weight bearing limitations may be present
NWB 3-4 wks
If MCL tear present with ACL tear, is MCL typically repaired?
No, MCL will heal during ACL rehab
If ACL and PCL both reconstructed, which protocol should be followed?
PCL
Are ACL reconstructions typically performed in skeletally immature?
No, but risk for instability is high
What 4 clinical signs may indicated that rewards from ACL reconstruction outweighs risks in skeletally immature?
older than 14
partial tear of >1/2 thickness
tear of posterolateral bundle
pivot shift grade B or greater
Are most PCL tears complete or partial?
Partial, often can be rehabbed (potential 1-2 wk return to sport)
What is typically used for PCL reconstruction
AT allograft, so no graft site morbidity
ROM restrictions post PCL reconstruction
limit to 70-90 or less for 2-4 wks
How long should resisted knee flexion be limited following PCL reconstruction
4 months or more due to high PCL stress with hamstring contraction
What are primary restraints to varus/rotational instability?
LCL, popliteus, popliteofibular ligament
Time frame for LCL reconstruction?
within 3 weeks to avoid retraction
Which meniscus undergoes degenerative changes quicker?
lateral.
Due to this, repeated excision more common with lateral injury
weight bearing limitations following meniscal repair
progressed over 8 wks.
If in outer 1/3 (vascularized): weight bearing in full extension.
Squatting restrictions post meniscus repair
less than 45 degrees for 4 weeks,
less than 90 degrees for 8 weeks
Meniscal transplant demographics
under 40, minimal OA, not TKA candidates, 2mm joint space
Restrictions post meniscal transplants
no running for one year.
often not candidates for plyometrics
Strongest predictor of functional limitations with knee OA?
quadriceps strength
How much weight loss is associated with moderate improvements in pain/function with knee OA
13.5lbs
Benefits of hyaluronic acid injections
joint lubrication, decreased swelling/inflammation
What does a lateral wedge accomplish for knee OA
limits knee adduction force, limit medial joint load.
Short term benefits only
Osteotomy for knee OA
Tibial for medial compartment
Femoral for lateral
Should posterior glides be used for PCL sacrificing TKA?
May stress cam/post, so no
What is important factor with use of NMES for quadriceps strength
early introduction
Indications for microfracture surgery
full thickness lesion with no osseous defect
Recovery from microfracture surgery
NWB for up to 4 weeks, 8 weeks till full weight bearing
risk factors for PFPS
female, quad tightness, hypermobile patella, weak knee extension, altered VMO response,
