The Knee Flashcards
Which side of the distal femur has more contact with the patella?
Lateral (medial has more contact with tibia than patella)
Which tibial condyle is longer?
medial
Because the tibia is vertical and the femur is slightly oblique, what angle to they create in standing at the knee?
~185° (slight valgus)
What knee angle is considered genu valgum?
> 185°
What angle is considered genu varum?
< 175°
Describe the mechanical axis between the hip and ankle in both normal standing & single-leg standing. How might this be relevant for a patient that demonstrates genu varum/valgum?
- hip is aligned directly over the ankle in the absence of anatomical dysfunction
- mechanical axis shifts medially in SLS, since the hips shift position
- the shifting axis in SLS combined with genu valgum/varum can overload supporting structures in the knee
What connective tissue makes up knee menisci?
fibrocartilage
Contrast the shapes of the medial vs lateral meniscus.
lateral is o-shaped, medial is c-shaped
What are the beginning and end of the meniscus called?
anterior and posterior horns
What are the 3 zones of the knee meniscus? Describe their blood supply, respectively.
- red zone: outer third, receives blood from capsular arteries
- red-white zone: middle third, poor blood supply
- white zone: central third, poor blood supply
What portion of the knee menisci is separated from the capsule? What is its blood supply?
posterior lateral corner of the lateral meniscus is separated from the capsule by the popliteus tendon & is relatively avascular.
List 6 attachments of the lateral knee meniscus to nearby structures.
- anteriorly to medial meniscus (transverse ligament)
- to the patella via thickening of anterior capsule (patellomeniscal ligament)
- posteriorly to the popliteus
- posteriorly to the posterior cruciate ligament (PCL)
- medial femoral condyle (meniscofemoral ligament)
- edge of the capsule (coronary ligaments)
List 6 attachments of the medial knee meniscus to nearby structures.
- edge of the capsule (coronary ligaments)
- anteriorly to lateral meniscus (transverse ligament)
- to the patella via thickening of anterior capsule (patellomeniscal ligament)
- posteriorly to semimembranosus muscle
- anterior horn attaches to the anterior cruciate ligament (ACL)
- posterior horn attaches to the posterior cruciate ligament (PCL)
Which knee meniscus is more mobile?
lateral meniscus
Describe the muscular attachments that can create movement of the knee menisci.
popliteus contractions can move the lateral meniscus, semimebranosus contractions can move the medial meniscus
List 4 functions of the knee menisci.
- increase contact area of femoral condyles on the tibial plateau
- assist with joint glide
- limit hyperextension
- provide cushion & support to the weight-bearing surfaces
Describe the innervation of the knee menisci.
nociceptors & joint mechanoreceptors (pain and proprioception can be altered after injury)
Describe the 3 regions of the lateral compartment of the knee and the reinforcing structures associated with each.
Anterior region: supported laterally by the lateral retinaculum
Middle region: reinforced by the distal ITB
Posterior region: reinforced by the arcuate complex
Describe the 2 layers of the lateral retinaculum. Which portion of the lateral knee compartment does the retinaculum reinforce?
- Superficial oblique layer: runs from the ITB to the lateral border of the patella & patellar tendon
- Transverse layer: undersurface of ITB to lateral patellar border
- reinforces the lateral portion of the anterior region of the lateral compartment
What 3 structures comprise the arcuate complex of the knee?
- lateral collateral ligament (LCL)
- arcuate ligament (reinforced by biceps femoris tendon)
- popliteus tendon
What are the attachments of the arcuate ligament of the knee?
posterior lateral femoral condyle to posterolateral tibia
What motions does the lateral collateral ligament of the knee restrain?
varus angulation of the tibia & excessive lateral rotation of the tibia
Describe how the contribution to knee stability provided by the LCL changes depending upon knee position.
- provides ~55% of the resistance to varus stress in 5° of flexion
- 69% with 25° flexion
(posterior structures are on slack in flexed position)
The posterior third of the medial compartment of the knee is reinforced by what two soft tissue structures?
- posterior oblique ligament (thickening of medial capsular ligament)
- semimembranosus muscle
What is the posterior oblique ligament of the knee and what are its attachments?
- thickening of the medial capsular ligament
- from the adductor tubercle of the femur to the tibia and posterior capsule
- also attaches to the semimembranosus tendon sheath and oblique popliteal ligament
What are 3 functions of the posterior oblique ligament?
- reinforces the posteromedial aspect of the knee joint
- provides resistance to valgus forces near full extension
- provides support as the knee moves into flexion (semimembranosus attachment)
Describe how the contribution to knee stability provided by the MCL changes depending upon knee position.
- provides ~57% of the resistance to valgus stress in 5° of flexion
- 78% with 25° flexion
In addition to the MCL, what intra-articular ligamentous structure plays a supportive role in resisting valgus forces on the knee?
PCL (MCL/PCL tear results in the greatest valgus of any ligament injury combination)
Describe the divisions and attachments of the MCL
- divided into superficial and deep layers (bursa in between)
- deep layer is divided into meniscofemoral and meniscotibial ligaments
- superficial layer connects the medial femoral condyle and the tibia below pes anserine (also semimembranosus and vastus medialis)
Describe the general blood supply to the MCL
rich blood supply, so it heals well following injury
Describe the main soft tissue structures that support both the medial and lateral posterior knee joint capsule.
- Laterally: arcuate popliteal ligament & popliteus
- Medially: semimembranosus tendon (and its expansion) & oblique popliteal ligament (medially)
Describe the soft tissue structures associated with lateral knee joint capsule
lateral retinaculum, LCL is loosely attached to the capsule fibers and runs to the head of the fibula, dividing the biceps femoris tendon
Why are the ACL and PCL called “cruciate” ligaments?
the form a cross in the sagittal plane, providing joint stability
What is the blood supply to the ACL? PCL?
both are supplied by the genicular arteries (anastamosis/branches from of popliteal artery)
Describe the innervation of the ACL & PCL.
both innervated by branches from the tibial nerve
Aside from providing mechanical stability, what other two roles do the ACL and PCL play in knee joint function?
- via mechanoreceptors (Ruffini corpuscles, Pacinian corpuscles, Golgi tendon organs), they give the brain information about the location of the joint in space and stresses that the joint is undergoing
- mechanoreceptors and free nerve endings provide “preparatory” information to enhance muscular responses to provide dynamic stabilization
What are the proximal and distal attachments of the ACL?
lateral femoral condyle (posteromedial corner) to area anteromedial to the intercondylar eminence (anterior tibial plateau)
Is the ACL taut in knee flexion or knee extension? What does this mean for clinical testing for ACL tears?
trick question: both
- the ligament is divided into the anterior medial bundle (tight in flexion) & the posterior lateral bundle (tight in full extension through 20° of flexion)
- if anterior medial bundle is torn, but posterior lateral bundle is intact, Anterior Drawer test can be positive.
The ACL provides 85% of resistance to anterior tibial translation in what degree(s) of knee flexion?
30° of knee flexion
In addition to anterior tibial translation, what other movements of the tibia does the ACL also check?
medial/internal rotation, hyperextension, and secondary support against varus/valgus forces
What is the most common mechanism for ACL injury?
deceleration force in slight flexion combined with medial or lateral tibial rotation
The ACL can be damaged when a deceleration force in slight knee flexion is combined with either medial or lateral tibial rotation. Why both types of rotation?
Medial tibial rotation: ACL winds around PCL
Lateral tibial rotation: ACL stretches over the lateral condyle, creating strain
How do knee muscles contribute to & relieve strain on the ACL?
- quads can generate anterior tibial translation near full extension
- hamstrings and soleus can create posterior tibial translation
Describe the attachments of the PCL.
travels from the medial femoral condyle (lateral aspect) to posterior tibial plateau
The PCL provides most of it’s resistance to posterior tibial translation in what general knee position?
flexion (anterolateral bundle makes up 95% of PCL)
What are the two divisions of the PCL?
anterolateral bundle (95%) and posteromedial bundle (5%)
The anterolateral bundle of the PCL is taut in what general knee position?
flexion
The posteromedial bundle of the PCL is taut in what general knee position?
extension
The PCL provides 95% of resistance to posterior tibial translation in what degree(s) of knee flexion
30°-90° of knee flexion
The PCL doesn’t check posterior tibial translation as much in ranges close to knee extension. What 3 are secondary restraints against posterior translation in extension?
- MCL
- Popliteus
- The posterior capsule
Following a PCL rupture, the greatest posterior tibial translation will occur in what degree(s) of knee flexion? Why?
70°-90°of knee flexion; the secondary restrains (MCL, popliteus, posterior capsule) are on slack
What is the most common mechanism of PCL injury?
hyperflexion (PCL is most taut in flexion)
Direct tibial posterior translation injuries (e.g. dashboard injury) results in injury to what knee structures?
secondary structures like MCL, poplietus, and posterior capsule rather than PCL
Aside from posterior tibial translation, at 90° of knee flexion, the PCL plays a secondary role in resisting what other movement(s)?
secondary resistance to tibial external rotation, varus and valgus forces
The PCL provides secondary resistance to tibial external rotation in knee flexion. What other structure(s) provide(s) this resistance?
posterolateral corner (when both posterolateral corner & PCL are torn, increased tibial ER is seen in varying degrees of knee flexion)
How do the hamstring muscles affect strain on the PCL?
- contraction of the semimembranosus, semitendinosus, and biceps femoris produce posterior tibial translation in non-weightbearing and directly increase strain on PCL
In addition to the hamstrings, what 5 other muscles contribute to knee flexion?
- popliteus
- gastrocnemius
- sartorius
- gracilis
- tensor fascia lata (via ITB)
What action of the knee do the sartorius, gracilis, and tensor fascia lata all have in common?
knee flexion
The tensor fascia lata produces knee flexion in what position?
when the knee is already flexed
The knee flexors are all two-joint muscles except which two?
short head of biceps femoris and popliteus
In addition to knee flexion, what action of the knee do the popliteus, gracilis, sartorius, semimembranosus, and semitendinosus all have in common?
tibial medial/internal rotation (in knee flexion)
When the knee is in flexion, what 5 muscles produce tibial medial/internal rotation?
- popliteus
- gracilis
- sartorius
- semimembranosus
- semitendinosus
In addition to knee flexion, what action of the knee do the biceps femoris and tensor fascia lata have in common?
tibial lateral/external rotation (in knee flexion)
When the knee is in flexion, what 2 muscles produce tibial lateral/external rotation?
- biceps femoris
2. tensor fascia lata (via ITB)
What 3 muscles insert at the pes anserinus?
- sartorius
- gracilis
- semitendinosus
What secondary forces on the knee do the semimembranosus, semitendinosus, medial head of gastrocneumius, sartorius, gracilis all have in common?
they all create varus knee movement / check valgus forces
What 5 muscles can help check valgus forces on the knee?
- semimembranosus
- semitendinosus
- gracilis
- sartorius
- medial head of gastrocnemius
What secondary forces on the knee do the biceps femoris, lateral head of gastrocnemius, and popliteus all have in common?
they all create valgus knee movement / check varus forces
What 3 muscles can help check varus forces on the knee?
- biceps femoris
- lateral head of gastrocnemius
- popliteus
What is the screw home mechanism?
the tibia laterally/externally rotates at end-range knee extension & must medially/internally rotate to “unlock” and initiate knee flexion
During the squat and leg press, posterior shear forces / PCL strain are greatest in what degree(s) of knee flexion?
83°-105° of flexion
Contrast anterior shear / ACL strain forces in weight-bearing vs non-weight bearing exercise
no anterior shear / ACL strain in weight-bearing exercises like squats & leg presses; anterior shear develops in 40°-0° of knee flexion during exercises like knee extension (peaks in the last 10 degrees)
During knee extension exercises, when are forces on the ACL the greatest?
anterior shear force starts at 40° of knee flexion and peaks in the last 10 degrees to extension
To avoid anterior shear / ACL strain during knee extension exercises, what ROM should be avoided?
0°-40° of flexion
Describe the changes in the amount of contact between the patella and the femur as the knee moves through flexion.
- in full extension, the patella is loosely sitting in the trochlear groove; only the inferior pole is in contact with the femur
- the patella contacts the femur both medially and laterally by 20° of flexion
- contact area increases with further flexion, and by 45°, the middle of the patella is in contact with the femur
- by 90°, the upper third of the patella is in contact with the femur
- after 90°, the patellar contact shifts inferiorly and laterally, loading the odd facet
What are the 2 biomechanical factors that contribute to patellofemoral joint compression?
contact area size & force generation
What % of bodyweight are patellofemoral compressive forces in walking, jogging, and standing from a chair, respectively?
walking = 50% BW jogging = 3-4x BW sit-stand = 6.7x BW
Why do patellofemoral compression forces increase beyond 90° of knee flexion?
odd and lateral facets engage, but total contact area decreases
The medial facet of the patella bears the greatest compressive load in what degree(s) of knee flexion?
up to 70° of knee flexion
In knee flexion beyond 90°, what structure helps to dissipate patellar contact forces?
quadriceps tendon comes into contact with femoral groove
What 3 structural abnormalities can cause instability of the patella?
- shallow trochlear groove
- less prominent lateral femoral condyle (trochlear dysplasia)
- laxity of patellar soft tissue tethers
What is trochlear dysplasia?
less prominent lateral femoral condyle that causes patellar instability
What soft tissue structure provides the most resistance to lateral patellar movement?
medial patellofemoral ligament (60%)
The lateral patellofemoral ligament provides a tether between which two structures?
the patella & the ITB
What two lines make up the Q-angle?
ASIS to midpoint of the patella & midpoint of patella to tibial tuberosity
What are considered normal Q-angles for men and women?
men: 10°-15°, women: 15°-20°
What Q-angle is generally considered structurally abnormal? Why is this clinically relevant?
> 20°; can place a patient at risk for excessive lateral patellar forces
How can exercises be designed to minimize excessive patellofemoral compressive forces?
avoiding terminal 30° of knee extension during nonweight-bearing exercise & avoiding greater than 90° of flexion during weight-bearing exercise
If a patient presents with anterior knee pain, but their patellofemoral examination is negative, what other structure should be tested?
PCL (can be a source of anterior knee pain - check patient history for instances of potential trauma, i.e. old injuries)
What can the timing of knee joint swelling following injury tell you about the structures involved?
immediate swelling can be internal joint trauma or hemarthrosis; delayed onset of hours or days indicates a synovial fluid response
What are the Ottawa Knee Rules and how are they implemented?
- age> 55
- isolated tenderness of the patella (no other bony tenderness)
- tenderness of fibular head
- inability to flex the knee to 90°
- inability to bear weight both immediately & in the ER (4 steps, limping is okay)
- if any of these are present, refer for imaging (x-ray)
- if not, no imaging is necessary
- 100% sensitivity for fracture
If a patient complains of knee pain that is “shooting”, “burning”, or travels up/down the leg, what other areas may be involved?
hip, spine, and S.I. may be involved
If a patient with knee pain is between 5-17 years old and presents with a largely negative knee examination, what diagnosis should be considered? What other clinical findings would support this diagnosis?
Slipped Capital Femoral Epiphysis / Legg-Calve-Perthes
- (+) FABER
- Limited hip IR
- Excessive hip ER
What disease commonly causes bilateral knee pain and swelling?
Lyme Disease (deer tick bite)
In a patient with knee pain, what other areas should be screened?
lumbar spine, SIJ, hip, and ankle
Describe the performance and grading of the Knee Effusion measurement technique described in the monograph. How reliable is this method?
- push medial knee swelling proximally
- sweep from mid-thigh to lateral knee
- observe the return of swelling
- grading:
0: no swelling returns
Trace: small amount returns
1+: returns with lateral sweep
2+: returns without lateral sweep
3+: swelling does not move at all
- kappa 0.75
What did Lynch & Logerstedt et al discover about the relationship between knee joint effusion and quadriceps muscle activation?
Although saline injections diminish quad muscle function, Lynch et al found that quad activation failure(“inhibition”) was not seen in even very large knee joint effusions following ACL rupture
How is voluntary activation of the quadriceps affected in patients with ACL injury and/or anterior knee pain?
voluntary activation can be as much as 10%-12% less (can be seen on both involved and uninvolved limbs)
What are the 2 types of factors that can lead to passive resistance to knee joint motion? How are they distinguished during the physical examination?
external & internal; therapist end feel
What are 3 external factors that can lead to passive resistance to knee joint motion?
- capsular tightness
- scarring
- loss of musculotendinous flexibility
What are 3 internal factors that can lead to passive resistance of knee joint motion?
- bony or meniscal block
- loose body
- component of surgery (e.g. poorly placed graft or ill-fitting prosthesis)
Why might both a soft & a firm end feel for knee flexion be considered “normal”?
it depends on hip position:
- if hip is flexed, knee flexion end feel should be soft (soft tissue approximation of calf & thigh
- if hip is extended, knee flexion end feel should be firm (anterior muscle tension)
What end feel for knee extension is considered “normal”? How does the leg position affect the limiting structures?
- end feel for knee extension should be firm
- it depends on hip position:
- if hip is extended, knee extension is limited by the capsule & ligaments
- if hip is flexed, knee extension is limited by muscle
What are the landmarks for measuring knee ROM?
- axis: lateral epicondyle
- stationary arm: midline of femur
- moving arm: lateral malleolus
List 4 tests for ACL rupture.
- Anterior drawer test
- Lachman test
- Pivot shift test
- Lelli (Lever) test
While administering the Anterior Drawer test, what additional motions should be noted and why?
- Tibial rotation
- Excess medial rotation: Lateral Capsule injury or Anterolateral Instability
- Excess lateral rotation: MCL, Medial Capsule, or Posterior Oblique Ligament injury
What injury might cause a false positive Anterior Drawer test?
PCL rupture (starts in subluxation)
Describe initial testing of an MCL injury
Valgus Stress test in full extension > 5mm; check PCL and ACL
Describe initial testing of an LCL injury
Varus Stress test
Describe initial testing of a PCL injury
Posterior Drawer test
Describe initial testing of an ACL injury
Lachman test
Describe initial testing of a Posterolateral Corner injury
Posterior Drawer increased 30° of flexion and normal at 90°
Describe initial testing of a Meniscus injury
McMurray test, Apley Compression test, joint line tenderness, Thessaly test
Describe initial testing of a Patellofemoral injury
Quadriceps make test, Step-down test, Patellar Tilt test
What is the most specific test for MCL injury?
Valgus Stress test at 30° of flexion (> 5mm)
What is the most specific test for LCL injury?
Varus Stress test at 30° of flexion (isolates LCL)
What are the most specific tests for PCL injury?
Posterior Sag & Quadriceps Activation test that shows anterior tibial translation
What is the most specific test for ACL injury?
Lachman test with empty endfeel
What is the most specific test for a Posterolateral Corner injury?
Prone External Rotation test > 10° compared to uninvolved side
What are the most specific tests for a Meniscus injury?
Meniscal Pathology Composite Score: - history of catching/locking - joint line tenderness - pain with forced hyperextension - pain with maximal knee passive flexion - pain or audible click with McMurray (5/5 = 92.3% likelihood, 3/5 = 75%)
What are the most specific tests for a Patellofemoral injury?
Pain during resisted isometric quad contraction, Squatting, & Palpation
If a Posterior Drawer test is (+), what additional structures should be assessed and how?
Assess Posterolateral Corner by externally rotating tibia during the test
If a Posterior Drawer test is (+), what additional structures should be assessed and how?
Assess Posterolateral Corner by externally rotating tibia during the test
What structures constitute the Posterolateral Border of the knee?
- Arcuate ligament
- LCL
- Popliteus tendon
- Lateral head of the Gastrocnemius
Describe the general sensitivity and specificity of joint line tenderness in diagnosing meniscal injuries
Sensitive, but not specific
What are the 5 tests that comprise the Meniscal Pathology Composite Score?
- history of catching/locking
- joint line tenderness
- pain with forced hyperextension
- pain with maximal knee passive flexion
- pain/click with McMurray test
How specific is the Meniscal Pathology Composite Score?
5/5 = 92.3% sp 3/5 = 75% sp
How far can a patella normally be displaced during the physical exam?
25%-50% of its width
In what knee position is the patella maximally subluxed?
20°-30° of knee flexion
How is the flexibility of the lateral retinaculum tested?
Patellar Tilt test
Describe the Patellar Tilt test
- knee is in 20° of flexion
- examiner’s thumb tilts the lateral edge of the patella upward
- normally, the patella can be tilted upward above the horizontal, but a tight retinaculum will be decreased vs uninvolved side
What 5 MMTs should be performed during the examination of someone with suspected Patellofemoral Pain?
- knee flexion (sitting)
- knee extension (sitting)
- hip abduction (side-lying)
- hip extension (prone)
- hip external rotators (prone, knee flexed)
Which knee functional tests do the monograph authors recommend?
- Hop Tests:
- Single Hop
- 6m Timed Hop
- Triple Hop
- Cross-Over Hop
2, Dynamic Balance Tests:
- Star Excursion Balance test
- Y-Balance test
Because the Star Excursion Balance test has such a significant learning curve, what is recommended by the authors for administering the test?
6 practice trials
When administering the Star Excursion Balance test, what are clinically significant differences between sides?
limb difference in the anterior direction of more than 4 cm showed greater than 2.5x likelihood of injury risk in high school basketball players
What 4 knee functional tests do the authors recommended for elderly and osteoarthritic patients?
- Timed Stair-climbing Test
- Six-Minute Walk Test
- Timed Up-and-Go Test
- Five Time Sit-to-Stand Test
What are red flags in a knee evaluation/examination?
- rapid weight gain or loss
- night pain unrelated to movement
- unexplained joint aching and malaise
What is the loose-packed position of the tibio-femoral joint?
25°-30° of knee flexion
Joint mobilization of the tibio-femoral joint should initially be performed in what position?
Loose-packed position (25°-30° knee flexion)
What exercise is recommended by the monograph authors to combine with joint mobilization as a frequent home exercise?
wall slides (with optional overpressure from opposite limb / hands)
What home exercise is recommended by monograph authors to increase knee extension?
Low-load prolonged stretch (seated bag hangs for 10-20 minutes)
When performing seated bag hangs to increase knee extension, why is ankle position important?
Keeping the ankle dorsiflexed can create a knee flexion force against the stretch via gastrocnemius tension. With the foot plantarflexed, the moment arm of the gastrocnemius as a knee flexor is decreased.
In what knee position should patellar mobilizations initially be performed?
full extension
What device is recommended by the monograph authors to address difficulty with restoring knee extension?
Drop-out casts
How should inferior patellar mobilizations be progressed and why?
begin in full extension, but restrictions may be more pronounced in greater degrees of flexion, so mobilizations can be performed with more flexion.
How can hamstring muscle tightness affect the patellofemoral joint?
tight hamstrings limit knee flexion, which increases patellofemoral compression
What 10 motions should be included in a knee flexibility examination?
- hip IR
- hip ER
- hip flexion
- hip extension
- prone knee flexion / Ely test
- straight leg raise
- dorsiflexion with knee flexed
- dorsiflexion with knee extended
- Ober test
- Thomas test (rectus femoris)`
What static stretching dosage do the monograph authors recommend to increase muscle length?
3-4 x 30-second stretches (increased frequency depending on tightness)
What muscle strength finding is nearly ubiquitous in most cases of knee injury or pathology, according to the monograph authors?
quadriceps weakness
What is the functional consequence of quad weakness in the gait cycle?
decreased knee excursion during the stance phase
What is the relationship between quad strength and older adults?
quadriceps weakness is correlated with an increased risk of falls in the elderly
Stim is a beneficial addition to volitional exercise if quadriceps strength is within what parameters?
quadriceps strength deficit of 15% to 20% or more compared to the uninvolved quad will benefit from the addition of e-stim
List 6 examples of Neuromuscular Training given by the monograph authors.
- Balance exercise
- Dynamic joint stability training
- Perturbation exercises
- Plyometric drills
- Agility & coordination training
- Sport-specific exercises
What is the hamstring-to-quadriceps strength ratio for return to sport, according to Wilk et al?
<66% for males, >75% for females
List 4 examples of Dynamic stability training given by the monograph authors.
- “Star” exercises in frontal, sagittal, and diagonal planes
- lateral lunge drills
- cone stepping at various speeds
When teaching proper jumping and landing technique, how should the patient be cued?
“Land softly on the toes with the knees slightly flexed”
Describe the 3 phases/timeframes for perturbation training, as described by the monograph authors.
- Early phase (treatments 1-3)
- Middle phase (treatments 4-7)
- Late phase
(treatment 8-10)
Describe early phase (treatments 1-3) perturbation training with the tilt board.
bilateral 1st treatment, progress to unilateral with eyes straight ahead; inform pt of direction/timing of tilt; less force medial than lateral; low magnitude force applied; cue patient to maintain balance / recover quickly
Describe middle phase (treatments 4-7) perturbation training with the tilt board.
unilateral (avoid forefoot adduction/abduction); apply unexpected forces with rapid, increasing magnitude of force; hold board to the floor in one direction and unexpectedly release; begin to add distractions (ball toss, stick work); look for rapid return to stable base after perturbation
Describe late phase (treatments 8-10) perturbation training with the tilt board.
unilateral; place foot at diagonal; increased magnitude force with random directions; little to no delay between perturbations; increase speed of distraction and magnitude of direction (consider sport-specific positions); look form minimal sway from stable stance at rest following perturbation
Describe early phase (treatments 1-3) perturbation training with the stationary + tilt board set-up.
eyes straight ahead, equal weight-bearing on both; inform pt of direction/timing of movement; slow, low magnitude application of force; cue pt to maintain equal weight-bearing bilaterally (watch for off-loading of affected side as difficulty increases); board only moves 1-2 inches
Describe middle phase (treatments 4-7) perturbation training with the stationary + tilt board set-up.
eyes straight ahead, equal weight-bearing on both; do not inform pt of direction of perturbation; distraction with ball tosses; look for equal weight-bearing bilaterally, make sure pt does not stiffen leg
Describe late phase (treatments 8-10) perturbation training with the stationary + tilt board set-up.
eyes straight ahead, equal weight-bearing on both; increased magnitude of force with random directions and little to no delay between applications; increase speed/magnitude of distraction (consider sport-specific stance - forward/backward split); cue patient to react as you remove force (avoid rebound board movement)
How do the monograph authors suggest dosing perturbation exercise? How should tilt board training be cued?
3 sets of 1 minute per side; “when I push the tilt board, resist the exact movement in speed and magnitude. The board should remain in the same place. Do not overpower me and move the board away, and do not let me overpower you.”
How should plyometric exercise like jumping and landing be introduced and progressed?
leg press machine, hopping in place, lateral and forward/backward jumping, bounding, then box jumping; progress from double-leg to single-leg
Define motor control.
purposeful, coordinated movements produced by the central nervous system in its interaction with the body & its environment.
What term is defined as purposeful, coordinated movements produced by the central nervous system in its interaction with the body & its environment?
motor control
What is the purpose of balance training?
focus on awareness of posture and the position of the body in space with the objective of maintaining upright posture without compromising the base of support
Which neuromuscular training approach focuses on awareness of posture and the position of the body in space with the objective of maintaining upright posture without compromising the base of support?
balance training
What is the purpose of dynamic joint stability exercise?
to allow the body to freely and voluntarily move in an efficient manner
Which neuromuscular training approach is performed with the goal of allowing the body to freely and voluntarily move in an efficient manner?
dynamic joint stability exercises
What is the purpose of perturbation exercise?
to promote coordination in muscle activity and to teach subjects to dynamically stabilize the knee in response to unexpected disturbances
What is the purpose of plyometric drills?
increase power / technical performance & control and dissipate forces
What is the purpose of agility & coordination training?
to allow the patient to adapt to quick changes in direction
Which neuromuscular training approach is performed with the goals of promoting coordination in muscle activity & teaching subjects to dynamically stabilize the knee in response to unexpected disturbances?
perturbation training
Which neuromuscular training approach is performed with the goals of increasing power / technical performance & controlling and dissipating forces?
plyometric drills
Which neuromuscular training approach is performed with the goal of allowing the patient to adapt to quick changes in direction?
agility & coordination training
List 7 examples of agility & coordination exercises.
- cutting drills (progress to 45° cutting & cutting/spinning drills)
- quick changes in acceleration and deceleration (shuttle runs)
- speed & precision drills
- side-slides
- carioca drills
- agility ladder drills
- sport-specific ball or stick activity
List the 5 categories in the Knee Soreness Rules.
- knee soreness during warm-up that continues
- knee soreness during warm-up that goes away
- knee soreness during warm-up that goes away but redevelops during session
- knee soreness the day after exercise (not muscle soreness)
- no knee soreness
According to the Knee Soreness Rules, if a patient experiences knee soreness during warm-up that continues after, which action should be taken?
2 days off, drop down 1 step
According to the Knee Soreness Rules, if a patient experiences knee soreness during warm-up that goes away, which action should be taken?
stay at step that led to soreness
According to the Knee Soreness Rules, if a patient experiences knee soreness during warm-up that goes away but redevelops during session, which action should be taken?
2 days off, drop down 1 step
According to the Knee Soreness Rules, if a patient experiences knee soreness the day after exercise (no muscle soreness), which action should be taken?
1 day off, do not advance program to the next step
According to the Knee Soreness Rules, if a patient experiences no knee soreness during warm-up or during exercise, which action should be taken?
advance 1 step per week or as instructed by health care provider
Which two diagnoses are most likely to benefit from patellar taping?
PFP and knee OA
How should patellar taping be applied and assessed? Which directions are most effective?
McConnell suggest basing technique on patellar position, but Fitzgerald & McClure note that assessment of patellar position had no influence on the success of symptom relief; conflicting evidence on direction: medial is most traditional, but in some cases, lateral is more effective; the monograph authors suggest that the PT tapes in one direction & reassessing (if 50% or greater reduction in pain is not achieved, try taping in an alternate direction)
What is the average healing timeframe for tendonitis?
3-4 weeks
What is the average healing timeframe for tendon lacerations?
5 weeks to 6 months
What is the average healing timeframe for exercise-induced muscle injury?
24 hours to 2 weeks
What is the average healing timeframe for a grade I muscle injury?
24 hours to 1 month
What is the average healing timeframe for a grade II muscle injury?
4 days to 3 months
What is the average healing timeframe for a grade III muscle injury?
3 weeks to 6 months
What is the average healing timeframe for a grade I ligament injury?
24 hours to 2 weeks
What is the average healing timeframe for a grade II ligament injury?
3 weeks to 6 months
What is the average healing timeframe for a grade III ligament injury?
3 weeks to 6 months
What is the average healing timeframe for a ligament graft?
2 months to 2 years
What is the average healing timeframe for bone?
5 weeks to 3 months
What is the average healing timeframe for an articular cartilage repair?
2 months to 2 years
In order to perform the tests included in the Screening Guidelines for Anterior Cruciate Ligament Injury, what 5 criteria must first be met?
- ACL tear only (no meniscus or concomitant ligament injury)
- full pain-free ROM
- no knee joint effusion
- quadriceps strength is > 70% of uninvolved side
- pain-free single-leg hopping
List the 4 tests included in the Screening Guidelines for Anterior Cruciate Ligament Injury that indicate that a patient as a “coper” (i.e. is more likely to respond favorably to conservative management without surgery).
- Noyes Hop Tests 80% or greater compared to uninvolved side (can use functional knee brace)
- Knee Outcome Survery ADL score 80% or greater
- GROC (0-100 compared to pre-injury) 60% or greater
- no more than one episode of giving way since injury
What must a patient with an ACL injury demonstrate in order to be considered a true “coper”?
- Demonstrate rehab candidacy via ACL Screening Guidelines
- Complete 10-treatment perturbation training program (coupled with agility training & strengthening)
- ## resume full participation in high level (Level I or II) sports for a full year
What are Level I sporting activities? Give examples.
those that encompass jumping, cutting, and pivoting types of maneuvers for 50+ hours per year (e.g. soccer, football, basketball)
What are Level II sporting activities? Give examples.
those that involve lateral motion (e.g. racquet sports, skiing)
When a hamstring tendon graft is used in ACL reconstruction surgery, what must be kept in mind during the rehab process?
Hamstring strength may be okay, but if full extension isn’t achieved & maintained, the graft harvest site (semitendinosus) may adhere to surrounding tissue. With rapid motions such as stumbling / turning quickly, the adhesions can be pulled loose, and the patient will feel a pull or pop in the medial hamstring. Local bruising may also develop.
When treating a patient following an ACL reconstruction using a hamstring tendon graft, they stumble / turn quickly and feel a pop in their medial hamstring area. A visible bruise develops. What action should be taken?
None. In the absence of other pain or dysfunction, it is likely that the hamstring graft site adhered to surrounding tissue, and the pop was the adhesion releasing. The patient should recover naturally, and this usually does not recur.
In order to optimize outcomes following ACL reconstruction, what are 2 main goals of the pre-hab process?
- full knee extension
2. “calm knee” a.k.a resolution of the acute inflammatory process
Following ACL reconstruction, at what point is the graft the weakest? How does this affect exercise selection & progression?
- Weakest at 12 weeks
- Quadriceps strength should be fully developed at this point to create dynamic stability that protects the graft (open-chain exercise may be better than closed chain for isolating quad strength without stressing the graft)
Why should quadriceps strength be prioritized over hamstring strength following ACL reconstruction?
- quad weakness is nearly universal
- decreased quad strength is correlated with poor post-op function
- strong quads decrease stress on the graft via dynamic knee stability
- hamstring strength tends to recover without focus intervention even when it is the source of the graft
Following ACL reconstruction, what extra precautions must be taken if concurrent meniscal repair is also performed?
avoid weight-bearing flexion past 45° for the first month
Following ACL reconstruction, what extra precautions must be taken if there is concurrent chondral damage or chondroplasty is performed?
restricted weight-bearing in the first 3-4 weeks
Following ACL reconstruction, what extra precautions must be taken if concurrent partial meniscectomy is also performed?
no modifications; generally managed symptomatically if necessary
How is an ACL reconstruction affected by a concurrent MCL injury?
Since a successful ACL reconstruction typically provides a stable healing environment for the MCL (even a grade III), it rarely surgically repaired. Regular ACL rehab guidelines are followed, though therapists can opt to restrict lateral / rotation motions, avoiding internal rotation positions in weight-bearing, and generally over-stressing the medial knee until weeks 4-6 post-op
How does an ACL reconstruction with a concurrent MCL injury differ from a reconstruction with a concurrent PCL injury?
- MCL can heal without surgical repair if the ACL reconstruction is successful
- PCL reconstruction is more at risk for developing graft laxity and is less protected by the ACL reconstruction, so protecting the PCL graft takes priority over the ACL and the rehab process is much longer and more complicated.
What are 3 reasons that a patient might have anterior knee pain following an ACL reconstruction?
- the central third of the patellar tendon may be used as an ACL graft
- the infrapatellar fat pad is perforated by the arthroscope during the surgery
- the infrapatellar fat pad is partially resected so that the surgeon can see the ACL site
What 6 measures have been suggested to determine a successful outcome following ACL reconstruction?
- less than mild persistent effusion
- greater than 90% quad and hamstring strength
- absence of giving way episodes
- participation in 1 or 2 seasons of sports (pre-injury level)
- sports-specific sections of patient-reported outcome measures
- ADL-specific sections of patient-reported outcome measures
One year after ACL reconstruction, what percentage of patients return to athletic participation?
67% (most do not return to pre-injury activity level, citing fear of return to sport as a factor)
How much more likely is a female to tear her ACL than a male?
4-8x more likely
What is the most common mechanism of ACL tears?
non-contact; tibia internally rotates on a femur that is externally rotating femur (torsional stress)
How effective are ACL injury prevention programs?
programs that incorporate strengthening & proximal control exercises reduced injury risk by 68% and 67% respectively (greatest in female athletes)
What are the 5 elements of the ACL injury prevention program suggested by Sugimoto et al?
- multi-planar components
- both unilateral and bilateral activities (ACL often occurs in single-limb stance)
- incorporate unanticipated or reaction-type movements (simulate sports)
- emphasize correct foot position and muscle coordination during cutting & dynamic movements
- consider implications of playing surface, fatigue, and bracing
What is the prognosis of PCL tears compared to ACL tears?
most PCL injuries are grade I and II tears and are treated nonoperatively, since few patients will develop functional instability. Healing is higher than ACL injuries, and most return to sport within 2-4 weeks. Grade III (complete) PCL tears are usually able to return to sport at about 3 months. If there is still pain and dysfunction after 3 months, surgical outcomes are good, with most patients returning to activity at the same or similar level.
During the early phase of rehab for a PCL tear, what muscle is particularly emphasized? What then typically follows?
- quad strength is emphasized
- then, the focus shifts to proprioception, balance, coordination, and co-activation of antagonist muscles (goal is to decrease tibiofemoral sheer force during active knee flexion/extension)
- if pain-free, then agility & coordination training can begin
Why would a patient with a PCL tear be immobilized & for how long?
grade III tear: immobilized in extension for 2-4 weeks to reduce posterior subluxation caused by hamstrings
What precautions should be taken in the rehab of an acute grade III PCL tear?
- immobilized in extension for 2-4 weeks
- avoid knee flexion past 70°
- avoid isolated hamstring exercise
- emphasize quad strengthening
What is the relationship between PCL laxity and functional outcomes? Between PCL laxity and concomitant injury?
Several prospective studies show no correlation between laxity and outcomes. However, as the grade of posterior tibial translation increases, so does the likelihood of meniscus, capsule, and posterolateral corner injury.
What would warrant surgical reconstruction of the PCL?
- over 3 months of conservative care without continued pain and disability
- concomitant injury of meniscus, capsule, or posterolateral corner
Following PCL reconstruction, what knee positioning typically puts the greatest amount of tension on the graft? How does this affect exercises post-operatively?
between 70°-90° of flexion; flexion beyond this range is limited for the first 2-4 weeks post-op
Which resisted movements should be avoided following a PCL reconstruction?
Knee flexion greater than 90° should be limited for the first 2-4 weeks post-op; Resisted knee flexion should be avoided until 8 weeks post-op; Resisted knee extension should be limited between 100° and 60°;
Following PCL reconstruction, through what range should quadriceps / knee extension strengthening exercise be performed, according to the authors? Why?
60°-0°; Posterior / PCL shear forces are lower in this range
How long should resisted knee flexion exercises be approached with caution following PCL reconstruction?
full healing of PCL (4 months post-op)
What three motions are checked by the Posterolateral corner (PLC)?
- excessive hyperextension
- varus angulation
- tibial external rotation
What are the 3 most common mechanism of posterolateral corner injury?
- postero-lateral-directed force to anteromedial tibia
- knee hyperextension
- severe tibial external rotation while knee is partially flexed
Primary PCL reconstruction is unlikely to sufficiently stabilize a knee if there is concomitant injury of what other structure?
posterolateral corner
List 6 surgical & non-surgical options for treating a meniscus injury.
- conservative rehab
- partial meniscectomy
- full meniscectomy
- debridement
- meniscus repair
- allograft transplantation
What are the 4 biological phases of cartilage maturation?
- proliferation
- transitional
- remodeling
- maturation
When is nonoperative treatment of a meniscus injury appropriate?
if there is a small tear in peripheral third (red zone)
What is the focus of nonoperative rehab of a meniscus injury?
- control swelling
- restore passive knee ROM
- minimize quad strength loss via nonweight-bearing exercise
- patient education to avoid squatting, pivoting, cutting, and running
What is the typical recovery time for a patient following meniscectomy?
2-6 weeks
What precautions should be taken to minimize compressive forces on the knee following meniscal repair?
weight-bearing is limited and should progress slowly over 8 weeks
Following surgical meniscus repair, when should balance and proprioceptive training begin?
when partial weight-bearing has been achieved
What knee ROM precautions should be observed following meniscal repair?
- in the first 4 weeks, activities in greater than 45° of flexion (e.g. squatting) are avoided
- loaded knee flexion beyond 90° is limited for 8 weeks
In addition to degeneration of articular cartilage, what two other conditions characterize knee joint arthritis?
- inflammation of the synovium
- changes to underlying subchondral bone (exposed bone can be painful at rest)
What is the strongest predictor of functional limitation in patients with knee osteoarthritis?
quad weakness
List load-reduction lifestyle home/modifications that patients with knee osteoarthritis may benefit from?
- shift from walking program to pool program
- use a rolling stool or workbench to minimize prolonged standing
- sorbothane insoles to increase shock absorption
- weight loss if overweight
How many pounds of weight loss results in moderate pain and function improvements in patients with knee osteoarthritis?
13.5 lbs
How long after hyaluronic acid injections can patient expect most of their pain relief to take place?
2-3 months post-injections
Following a femoral or high tibial osteotomy, what should be avoided during resistance training?
no resistance distal to the osteotomy site, so ankle weights should be placed on the thigh
When should weight-bearing be initiated following a Unicompartmental Knee Arthroplasty?
immediately
Which mobilization should be avoided in a patient with a TKA?
posterior tibial glide
What is the goal for ROM following TKA?
0°-120° or more of flexion
Strengthening of what muscle should be prioritized immediately following TKA?
quadriceps
What are the two elements that contribute to quadriceps weakness following TKA?
muscle atrophy & activation failure
Why is introducing kneeling training in physical therapy important following TKA?
patients were 7.5x more likely to report an improvement in kneeling at one year if given one training session at week 6 of post-op therapy.
List 5 features of a “stiff” postsurgical knee.
- tense effusion
- soft tissue distortion
- lack of quadriceps control
- inability to initiate a quad contraction
- restricted patellar mobility
- patient walks on a slightly flexed knee
- pain during active and passive movement
Compare and contrast healing timeframes following debridement or chondroplasty vs microfracture procedures to address knee chondral defects.
- both allow early PROM
- nonweight-bearing: debridement or chondroplasty is 3-5 days, but microfracture is 2-4 weeks
- full functional activities / intro impact activities: debridement or chondroplasty is 4 weeks, but microfracture is 4-8 months (depending on lesion size)
When performing knee extension strengthening in a patient with a history of patellar subluxation, what modifications do the authors suggest?
patellar taping & e-stim in 70°-90° of flexion to avoid subluxation at ranges at/near extension
When performing knee extension strengthening in a patient with a history of patellar subluxation, what modifications do the authors suggest?
patellar taping & e-stim in 70°-90° of flexion to avoid subluxation at ranges at/near extension
In order to avoid scarring following a lateral retinacular release, what technique should be initiated early in the post-op phase?
medial patellar mobilization (preferably superimposed on iliotibial band stretching)
In order to avoid scarring following a lateral retinacular release, what technique should be initiated early in the post-op phase?
medial patellar mobilization (preferably superimposed on iliotibial band stretching)
List 8 treatments for conservative management of Osgood-Schlatter Disease.
- rest
- ice
- quad stretching
- hamstring stretching
- iliotibial band stretching
- quad strengthening
- hamstring strengthening
- NSAIDs
What is Osgood-Schlatter Disease?
a traction apophysitis (inflammation of growth plates) of the patellar tendon insertion into the tibial tubercle
