Knee- ACL thru PT Rx Flashcards
What is the ACL?
Anterior Cruciate Ligament
Where does the ACL attach?
- centrally and anteriorly on the tibial plateau
- lateral aspect on the intercondylar fossa
Where does the ACL run?
superior, posterior and laterally
What excessive tibial motions does the ACL limit?
- limits anterior tibial translation
- IR of tibia
What is the ACL the primary restrain for?
excessive anterior tibial glide secondary restraint to tibial IR
What percentage of knee injuries are due to the ACL?
20%
What population are ACL injuries most often happening in?
younger and active biological females
What are non-modifiable risk factors for a non-contact ACL injury?
- biological sex (female)
- bony morphology
- congenital joint hypermobility
What biological sex is more prone to non-contact ACL injury?
- female tears> males
- 2 weeks following start of menstrual period
What bony morphologies are more prone to an ACL injury?
- narrow intercondylar femoral notch
- posterior tibial slope and hyperext both correlated with non-contact ACL injuries
What are some modifiable risk factors for the primary ACL injury?
- high shoe-surface interaction/friction
- High BMI
- Bracing - inconsistent benefit
- muscle strength
- altered loading patterns
- impaired trunk proprioception and kinesthesia
- greater activation of visual-motor strategy
Why can kinds of muscle strength issues be a modifiable risk factor for ACL injury?
- lower overall with ACL tears
- Ham to quad ratio strength
> lower in females vs. males
Why are the hamstrings important to the ACL?
BALANCE
- if hamstrings not as strong, quads pull the tibia forward and dont have the hamstrings to pull backwards
Why is impaired LE control a risk factor for ACL injury?
- increased dynamic knee valgus and hip adduction
- earlier and nearly 2x faster with impaired LE control (falling into it sooner, moving through it faster = excess stress)
- very good ability to visually identify high knee valgus angles with vertical drop jump test
Why is decreased knee flexion a risk factor for ACL injury??
larger GRF or harder landings so cant absorb landings
What can indicate poor control in landing with ACL?
- significant valgus movement
- knee medial to foot
What can indicate reduced control with the ACL?
- some valgus movement
- knee NOT entirely medial to foot
What shows GOOD control with the ACL upon landings?
- no valgus movement
- knee vertical with toes
Why can impaired trunk proprioception and kinesthesia be a risk factor for ACL injury?
- greater trunk lean toward support limb
- greater trunk rotation toward support limb
= less ability to counterbalance, more stress
What is a visual-motor strategy and why can be be a risk factor for ACL injury if used instead of sensory-motor strategy?
- using eyes to control movement instead of sensory or proprioceptive feedback = sports difficult to use vision
- take away visual for intervention to force proprioception use
What are risk factors for a secondary ACL injury?
- like primary ACL injury plus excessive femoral IR moment
- WORK ON ERs
What muscle group needs addressed MORE for a secondary ACL injury?
ER! Most prone to injury with weakness!!!
What is the etiology of a second ACL injury?
- non contact: 50-70%
- contact: 30%
What are functional questionnaires for the ACL?
- IKDC (international Knee Documentation Committee)
- KOS (knee outcome Survery)
What are symptoms of an ACL sprain?
consistent with any sprain plus:
- effusion, popping, and giving way following trauma
- WBing activities limited with likely giving way
What are signs of an ACL sprain found in ROM?
Consistent with any sprain plus:
- ROM: limited and painful, particularly into hyperext and IR (directions the ACL limits!)
What is the anterior drawer special test for the ACL?
- anterior drawer (+)
- stabilize foot with 90° knee flx in supine HL; glide tibia ant
- LR+= 1.6-8.3 and increases to 19 if effusion, popping, and giving way after trauma
- LR- = .1-.78
What is Lachman’s special test for the ACL?
- sens > spec
- in supine, stabilize femur @ 15° flx; glide tibia ant
- possible false negatives due to blocking of anterior glide :
- severe swelling tightens capsule
- Hamstring guarding
- meniscal tear
What is the pivot shift test for the ACL?
- in supine, hold tibial IR with valgus stress from 90° flx to full ext slowly
high spec
What should we know about the special tests for ACL?
others possibly positive for additional tissue damage, i.e. meniscus, MCL, etc.
What leads to muscle inhibition?
- pain
- swelling
- laxity
- disuse
What is a sign of ACL sprain in MMT/Muscle activity?
inhibition of quads due to:
- pain
- effusion (joint swelling)
- joint laxity or giving away
- muscle weakness/incoordination
Where can effusion (swelling) be found with ACL sprains?
- involved knee inhibition (42%)
- uninvolved knee inhibition (21-33%)
Is the amount of swelling always correlated with the amount of muscle inhibition?
NO
What can the arthrogenic muscle inhibition of quads with an ACL injury lead to?
- atrophy and more inhibition / weakness - deficits common out to 2 and 4 years post op and even in both LEs
What is the inhibition of quads determined by?
- observation, palpation and muscle testing
What is the “local muscle” of the knee?
vastus medialis
What should we know about return to LOWER RISK activity with an ACL tear?
- MOST can return to lower risk activity without surgery and with good outcomes
What are the 3 primary and early goals with an ACL tear?
- full to nearly full ROM, esp ext
- minimal to no swelling
- quads activation/ endurance/ coordination
How can we achieve full to nearly full ROM, esp ext with an ACL tear?
- immediate mobilization for ROM, pain, and minimizing immobilization effects (mod support)
When should we IDEALLY have full extension with an ACL injury?
no later than 4 weeks
What does the gain of full ext in the expected time frame predict?
extension at 12 weeks
How does achieving full extension post ACL injury contribute to a lower risk of OA?
- if ext not re-gained in 12 weeks = increased risk of knee age related joint changes
- joints healthiest when they can move through their full ranges, maintains the cartilage integrity with good stresses, which DECREASES THE RISK OF OA
Can you contract the quads fully without full knee ext?
NO
When is quad activation best?
with FULL EXTENSION
What test can measure good quad activity post ACL injury?
- SLR without extension lag
Quad set should be what percentage of the uninvolved side? Why is this misleading?
- ≥ 90% uninvolved side
- BUT uninvolved side could also be inhibited
What should we know about early WBing with ACL injury?
- without detrimental effects if symmetrical
- leads to better outcomes
What is there WEAK support for with ACL injury?
- cryotherapy
- continuous passive motion (CPM) devices
When should manual therapy be initiated with ACL injury?
post op
What should we use for muscle activation/coordination/strength with ACL injury?
- Neuromuscular Electrical Stimulation (NMES)
- significant increase in quad strength
- NO significant changes with function
- isometrics at varying angles based upon symptoms and commorbidities
When should the usage of NMES be discontinued?
- once quad index in ≥80% of uninvolved side
When is NMES even BETTER?
when done with a quad set, makes active intervention instead of passive; also MORE comfortable
What assumptions HAVE to be made about MET for ACL injury?
arthrogenic muscle inhibition
(NOT NO PAIN NO GAIN)
What can we gradually progress to with MET for ACL injury?
intense resistive training without inducing pain
What types of exercise should we emphasize with ACL injury?
both concentric and eccentric training
What are the general exercise guidelines for initial ACL loading with NON WB vs WBing activities?
- generally greater load on ACL with NON-WB due to working the quads, nothing opposing the anterior translation of the tibia! WB quads have the HS to counteract the glide of the tibia
- NON-wbing activities less of a concern than in the past
When are there the greatest loads with NON-Wbing and WBing activities?
within 50˚ of full extension with both
What should we know about general exercise guidelines with squatting, lunging, and leg press with initial ACL loading?
Load is…
- increased with knee beyond toes
- decreased with forward trunk lean
What are general exercise guidelines for ACL loading when walking?
- as much load as non-wbing knee ext due to repetitive terminal knee ext (need terminal knee ext to walk)
- several times greater than other WBing activities
What are Spaddy’s take home points with MET for ACL?
- Open kinetic chain and closed kinetic chain activities early and often, especially if they are walking and using correct trunk and LE control
- carefully and progressively work toward end range ext
Why should we emphasize hamstring strength and coordination?
- Hams > 66% of quad activity in males
- Hams > 75% of quad activity in females
- predicts LE control
Does normal strength equal proper neuromuscular control of LE?
NO ≠
What can we do with trunk proprioception and kinesthesia to help with neuromuscular training?
minimize lean and twist
What can we do to improve LE control using neuromuscular control?
- minimize excessive frontal and transverse plane motion
- promote sagittal plane knee and trunk flexion
- decrease GRF with softer landings
- Progressive speed and difficulty
- emphasize balance
How often and how long must we do MET for ACL injury?
at least 2-3x a week for 6-10 months
What should we do regarding each LE?
- work each LE individually as well as bilaterally for cross education
= less deficit compared to only exercising involved knee
What should we know about blood flow restriction for ACL injury?
- similar strength and hypertrophy as high intensity training
- good alternative if high intensity training cant be done otherwise
What is another PT rx for ACL injury to improve movement?
motor learning for improved movement patterns
What is the internal focus at the start with ACL injury?
on movement itself
What is the learning pace at the start?
slower
What is the carryover at the start?
Less
What resources are available for other factors at the start?
less (think too much)
How much psychological and psysiological stress is there at the start?
MORE
What kind of feedback is needed at the start?
More, simple
What is the focus with progressing?
on effect of movement
- ex: act like you’re sitting in a chair
- familiar
What is the learning pace with progressions?
Faster due to familiarity
How much carryover is there with progression?
MORE
What resources are available for other factors with progress?
More due to familiarity in premotor cortex
How much psychological and physiological stress is there with progression?
Less
How much feedback does the patient need with progress?
Less, but some may benefit from more detail if requested; simple
What are the benefits of motor learning with external focus for ACL PT rx?
- improved balance (central pressures)
- higher vertical jump
- more force production
- greater knee flexion
- softer landing (decreased GRF)
- improved coordination
What should we know about functional bracing for ACL injury?
- more beneficial than NOT with ACL deficiency
- conflicting support with ACL reconstruction
What can further motor learning with observation added to practice do to help with PT rx of ACL injury?
- with others by competition, motivation, responsibility
- post and real-time feedback including in slow motion
What should we know about plyometrics for ACL PT rx?
- vertical drop jump = similar loading to NON-wbing ext
- increased loading with rate of deceleration
