Knee Lectures 3 & 4

Question 1

Ligamentous Anatomy of the Knee

What is involved here???

Answer 1

• ACL
• PCL
• Posteromedial Corner PMC
  
  • MCL-Medial Collateral Lig.–superf. and deep
  • Posterior Oblique Ligament
• Posterolateral Corner PLC
  
  • ​Lateral (Fibular) Collateral Lig.– LCL
  • Popliteal Tendon
  • Popliteofibular ligament
  • Acruate Ligament

Question 2

Posteromedial Corner of Knee

Answer 2

see pics

Question 3

Posterolateral Corner of Knee

Answer 3

see pics

Question 4

Ligament Function

Rotation–NWB (*Fixed Femur)

Medial vs. Lateral Tibial Rotation

Answer 4

• Medial Tibial Rotation
  
  • ​ACL-2ndary
  • PCL-2ndary
• Lateral Tibial Rotation
  
  • ​PLC-Primary
  • MCL-Primary
  • PCL- Primary in 90deg FLEX
  • LCL-2ndary

Question 5

Ligament Function

Sagittal and Frontal Planes

Answer 5

• Anterior Translation
  
  • ​ACL- Primary
  • Meniscus, Capsule, Collaterals
• Posterior Translation
  
  • ​PCL-Primary
• Varus
  
  • ​LCL-Primary
  • Cruciates
• Valgus
  
  • ​MCL-Primary
  • Cruciates

Question 6

Anterior Cruciate Ligament

ACL

what is it?

Answer 6

• Primary Stabilizer
  
  • ​ANT Tibial translation
  • POST Femoral translation

Question 7

ACL in Extension

does what?

Answer 7

PL Bundle taut

restricts motion

Question 8

ACL in Flexion

does what ?

Answer 8

AM Bundle taut

restricts motion

*Anterior Drawer Test here**

Question 9

ACL @ ~20-30^o Flex.

does what ?

Answer 9

BOTH ACL & PCL contribute equally to LIMIT Ant. Tib. Translation

*Lachman Test here**

Question 10

The ACL is a Secondary Stabilizer for: 4 things

Answer 10

1. HyperEXTENSION
2. Varus + Valgus forces
3. Medial Tibial rotation
4. Lateral Femoral rotation

Question 11

ACL

Has ANT. attachment w/ _____________

Answer 11

has ANT. attachment w/ ANT. horn of MED. meniscus

Question 12

Saving the ________ drastically reduces risk of OA

Answer 12

Meniscus

Question 13

ACL Tears

Some stats….

Answer 13

• 200,000 tears/year in US
  
  • 100,000 reconstructions
• 0-13% pts w/ isolated ACL inj. dev. OA w/ 10-15yrs
  
  • drastic INC in OA rates w/ meniscectomy
    
    • _​_bc changing of articulation
• 41-50% pts who receive ACL reconstruction sx still dev. OA by 14yrs Post-OP
  
  • ​inj’d knee 4x MORE LIKELY to dev. OA vs. contralat. 10yrs latera
• Approx. 80% all ACL tears are from NON-contact inj’s

​***NOTE: do NOT need reconstruction Sx to avoid OA

***NOTE: ACL inj. does NOT mean you will get OA!!

Question 14

NON-Contact ACL Mech’s of Injury (MOI)

Answer 14

• Cutting combined w/ Deceleration
• Landing from jum in or near full EXT.
• Pivoting w/ knee near full EXT.
  
  • ​MED. rotation of tibia (LAT. rot. of femur)==ACL wraps around PCL
  • LAT. rotation of tibia (MED. rotation of femur)==ACL stretched over lateral femoral condyle
• HyperEXT.
• Dynamic Valgus

Question 15

STUDY: Biomechanical Measures of NMSK Control and Valgus Loading of the Knee Predict ACL Injury Risk in Female Athletes

Hewett et al., AJSM. 2005

Answer 15

• Female ado’s 4-6x greater chance of tearing ACL vs. males
• 205 female ado. soccer, basketball, volleyball players screened for NMSK control + Jt. loads during jump-landing tasks
• 9 ACL tears reported

*NOTE: more males WITH ACL tears

*NOTE: females have a GREATER RATE

Question 16

Valgus Loading & ACL Injury

Answer 16

• Looking @ Abnormal Frontal and Transverse Plane Mech’s
  
  • ​Knee motion AND knee loading during landing task are predictors of ACL injury.

see pics

Question 17

“Dynamic Valgus”

Multi-planar motion consisting of…

*remember there is a rotational component to this as well*

Answer 17

*Femoral ADDuction

*Knee ABDuction

*Ankle Eversion

Question 18

Abnormal Frontal & Transverse Plane Mech’s

Answer 18

ACL-injured athlete had 2.5x GREATER Knee ABD moment and 20% HIGHER GRF

Stance time was 16% SHORTER

****Ext. moment HIGHER on injured side

Question 19

Results and Discussion

Predicting ACL injury status:

Knee ABD moments

Answer 19

• Knee ABD moments have Sn of 78% and Sp of 73% predicting ACL injury status

Question 20

Results and Discussion

Predictors of ACL injury:

Sagittal plane knee and hip Flex.

Answer 20

Sag. plane knee and hip FLEX====NOT predictors of injury

Question 21

Results and Discussion

ACL injury predictors:

MM co-contraction quads + hams

Answer 21

• MM co-contraction of Quads+HS
  
  • ​proposed to DEC dynamic valgus and guard against excess. ANT TRANSLATION

Question 22

ACL Injury Assessmen

Lachman’s Test

Explain…

*NOTE: Tests POSTEROLATERAL BUNDLE better vs. Ant Drawer

Answer 22

• Pt. SUPINE w/ Knee flexed to 30^o (IMPORTANT!!!)
• Stabilize anteroLAT. DIST. femur (stabilize w/ OUTSIDE hand
• Mobilize w/ INSIDE hand —-translate TIBIA ANT. w/ OPP HAND (INSIDE HAND)
• (+) Test= Ant. translation of tibia BEYOND femur with “mushy” OR “soft” end-feel

*NOTE: Tests POSTEROLATERAL BUNDLE better vs. Ant Drawer

Question 23

ACL Injury ASSESS.

Anterior Drawer Test

Explain…

**NOTE: Tests ANTEROMEDIAL BUNDLE

Answer 23

* Pt SUPINE w/ knee flexed to 90^o

• Tibia in neut. rot.
• Thumbs IN jt. line​
  
  • fem. condyles ~1cm POST to AM Tibial plateau @ 90deg
• Translate tibia ANT—mildly forceful
• (+) Test= INCd ANT translation and soft end-feel

**NOTE: Tests ANTEROMEDIAL BUNDLE

Question 24

Clinical Exam of the ACL

Answer 24

• Sensitivity
  
  • ​TRUE POSITIVE rate
  • people who who are (+)–what proportion actually TEST (+)
• Specificity
  
  • ​TRUE NEG. rate
  • people who are (-)–what proportion actually TEST (-)
• PPV
  
  • ​how likely it is pt. HAS disease AFTER test POSITIVE
• NPV (depends on PREVALENCE)
  
  • ​how likely it is pt. DOES NOT HAVE disease if tested NEGATIVE
• + LR
  
  • ​likelihood that pt w/ POSITIVE TEST DOES have problem?
    
    • ​LR+ rules disease IN (over 10=better)
• -LR
  
  • ​likelihood my pt w/ NEG. TEST DOES NOT have prob?
    
    • ​LR- (very LOW (

Question 25

SnNOUT vs. SpPIN

Answer 25

* w/ high **Sensitivity, a Negative test rules OUT** * **​NEG. result on highly Sensitive test==useful** * w/ high **Specificity, a Positive test rules IN** * **​POS. result on highly Specific test==useful**

Question 26

LR Interpretation

Answer 26

see pics

Question 27

PCL

Answer 27

see pics

Question 28

Posterior Cruciate Ligament ## Footnote **PCL** **Anterior-Lat bundle vs. Posterior-Med bundle**

Answer 28

**PRIMARY "knee stabilizer"** **​​**120-150% ACL CSA * **Anterior-Lat. bundle** * **​​**MOST TAUT IN FLEX * **Posterior-Med. bundle** * **​**MOST TAUT IN EXTENSION

Question 29

PCL **PRIMARY _Restraint of:_**

Answer 29

* POST **Tibial** **translation** OR * ANT **Femoral** **translation**

Question 30

PCL ## Footnote **SECONDARY role in _LIMITING:_**

Answer 30

* **Femoral ER** * **Tibial IR**

Question 31

PCL MOI 4

Answer 31

* 1. HYPERFLEX * 2. Fall on **Flexed Knee** w/ foot in **PF** * **​(\*\*Fall on flexed knee w/ foot in DF==shattered patella)** * 3. HYPEREXT mech's * stepping in pot hole * 4. **Blow to ANT. Tibia---Dashboard** * **​\*classic PCL---MVA**

Question 32

PCL Injury ## Footnote **Differential Dx**

Answer 32

* Patellofemoral pain w/ **chronic PCL tears** * Need to R/O **Posterior Lateral complex involve.** * False + ACL testing * Consider **chondral lesions** when **MVA trauma involved** * **Meniscal tears @ POST horns**

Question 33

PCL Injury Assess. ## Footnote **Posterior Drawer Test** **Explain...**

Answer 33

* Pt is SUPINE ---- knee flexed to 90^o * Assess tibial plateau * Thumbs on **ANT jt line----apply POST force** * **(+) Test=** EXCESS. POST translation and/or soft end-feel * **\*90% Sn----10% FN's** * **\*90% Sp----10% FP's**

Question 34

PCL Injury Assess. **Post. Sag Sign/Godfrey's**

Answer 34

* STATIC TEST * **​pts knees _supported_** **and flexed to 90^o** * **(+) Test=** ANT. aspect of tibia appears to SAG * \*100% Sp * 79% Sn--21% FN's

Question 35

PCL Injury Assess. ## Footnote **Quad Activation Test**

Answer 35

* Pt lies SUPINE * **w/ PCL Tear-----tibia sags posteriorly** * **While sitting on pt's foot----instruct pt to perform ISOMETRIC Quads contraction** * "tell them to kick you off of their foot" * **(+) Test= Relocation of tibia** * **​**Sn= .54, 46% FN's * Sp= .97, 3% FP's

Question 36

Healing Potential of PCL

Answer 36

* healing possible **1 yr after injury W/ PROTECTION** * **​67-75% demo'd continuity on MRI @ 1 yr** * **tended to have Firm end-pt w/ residual laxity** * **\*\*Greater INITIAL laxity/COMBO'd injuries===LESS healing** * \*\*\*Adequate protection of **post translation of tibia (or ant. translation of Femur)** during rehab ====optimizes healing * not well tested

Question 37

Makes up **Posteromedial Corner** ## Footnote **PMC**

Answer 37

* MCL * superf * deep * Post. Oblique Ligament

Question 38

makes up **Posterolateral Corner** ## Footnote **PLC**

Answer 38

* Lateral (Fibular) Collateral Ligament: LCL * Popliteal Tendon * Popliteofibular Ligament * Acruate ligament

Question 39

The MCL Deep vs. Superficial

Answer 39

* **DEEP** **Layer****​** * **​**fibers that blend w/ **medial meniscus** * **SUPERFICIAL Layer** * **​**more **vascularized** and **FIRST to be injured**

Question 40

MCL ## Footnote **primarily RESISTS....** **also resists....**

Answer 40

primarily resists **Valgus stress** * ALSO resists..... * **LAT _Tibial_** **rotation** * **MED _Femoral_ rotation**

Question 41

MCL **Primarily responsible for controlling:** **and what does it do WITH the LCL?**

Answer 41

* **Primarily responsible:** * **​**controlling excessive **Valgus Forces** * **​MAINLY ANT. FIBERS** * **WITH LCL:** * **​**2\* responsibility in **preventing excess Femoral IR/Tibial ER**

Question 42

MCL ## Footnote **Differential Dx**

Answer 42

* Med. meniscus tear * ACL/PCL * Epiphyseal plate injury * Patella dislocation

Question 43

MCL Eval

Answer 43

* Palpation * **Valgus Stress Test** * **​1. Knee flexed @ 20-30^o** * **^​**now 78% valgus load absorbed by MCL * apply valgus stress * +Test= laxity/pain * Sn=86% * **2. Repeat @ 0^o** * **​**now 57% valgus load absorbed by MCL * **If laxity here====multiple lig. injury**

Question 44

MCL Eval **Valgus Stress @ 0^o** **If lot of lax===mult. lig. injury**

Answer 44

see pics

Question 45

Healing Potential of MCL

Answer 45

* **When combined w/ ACL Injury...** * **​**SUPERFICIAL MCL-----responded well to **bracing** * SUPERF & DEEP MCL----often req. **Sx** * **Tibial sided injury-----**not heal as well * **\*\*\*_Functional rehab important!!!_** * **_​_**AVOID **Valgus stress** * **​**work on OPP side----pulls them into **varus**

Question 46

Lateral Collateral Lig LCL info..

Answer 46

* NOT attached to capsule OR meniscus * Separated from meniscus **by Popliteus tendon**

Question 47

LCL ## Footnote **PRIMARILY resists.....** **ALSO resists....**

Answer 47

* PRIMARILY resists: **Varus stress** * **ALSO resists:** * **​**LAT **_Tibial_** rotation * MED **_Femoral_** rotation

Question 48

LCL **Diff Dx**

Answer 48

* ACL/PCL * PLC * Lat. meniscus * **ITB** * **Biceps Fem** * Popliteus

Question 49

LCL Eval

Answer 49

* Palpation of jt. line * **Varus Stress Test** * **​1. Knee flexed to 20-30⁰ (always start here)** * **​**now 55% Varus load absorbed by LCL * apply Varus stress * **(+) Test= laxity/pain** * **2. Repeat @ 0⁰** * **​**69% varus load absorbed by LCL * looking @ mult. lig. injury if more laxity/pain

Question 50

Posterolateral Corner ## Footnote **PLC** **STATIC Structures:**

Answer 50

* LCL * POST horn **lateral meniscus** * PL **capsule**

Question 51

Posterolateral Corner ## Footnote **PLC** **DYNAMIC Structures**

Answer 51

* ITB * Popliteus * Biceps Fem

Question 52

PLC Injuries

Answer 52

* **Posterolateral directed force TO** ANTEROMEDIAL **Tibia** * Knee HYPEREXT. * SEVERE **Tibial ER** w/ knee in **low FLEX angles** * **VARUS** forces to **Flexed Knee** * **Atraumatic** may present as **chronic laxity W/OUT PCL component** * **​**ER of **lat. tibial plateau** occurs around still intact PCL

Question 53

W/ the **PCL** ## Footnote **what is important????**

Answer 53

ROTATION

Question 54

PCL Injury Eval ## Footnote **Dial Test** **PLC===Rotation Important!!!**

Answer 54

* Pt is **Prone** w/ **knees FLEXED to 30^o and 90^o** * **MAXIMALLY ER lower leg** * **(+) Test= 15^o diff.** compared to **uninvolved leg** * **_Isolated PLC Injury:_** * **_​_**GREATER diff @ **30^o but _NOT @ 90_^o ** * **_Combined PCL/PLC Injury:_** * **_​_**Diff @ **30^o AND 90^o**

Question 55

Pre-OP and NON-OP Tx of **Ligament Tears** **Remember....Even though it is torn, you MAY NOT NEED Sx**

Answer 55

!!!!!!!!!!!!!!

Question 56

PREHAB!!! ## Footnote **Guiding Principles of Prehab Phase:**

Answer 56

* PREVENT **gross instability/giving way** * **​**Regardless of what is torn * PROTECT **injured structures** w/ **pot. to heal** * **​**MCL * **PCL in particular\*\*\*\*\*** * PROTECT any **risk of vessel/nerve injury** * RESTORE **ROM** and **Quadriceps Function**

Question 57

Prehab Phase ## Footnote **GOALS:**

Answer 57

* 0-120^o ROM **w/out Stiffness** * ​MD may limit to 90^o * PREVENT **mm atrophy** and **contracture** * **​**\*SLR w/out **lag** * \*Norm **patellar mobility** * MODIFY **gait patterns** to improve **overall** **function** * **​**Brace+Crutch reco'd

Question 58

Prehab Phase ## Footnote **Causes of _Concern:_**

Answer 58

* **IMMEDIATE REFERRAL** * ​S/S of **nerve or vessel compromise** * **​****Instability**that can NOT be managed w/**bracing or act. mods.** * Suspected **furthering of injury**

Question 59

Collateral (MCL/LCL) Lig. Injury **S/S**

Answer 59

* Varus (**LCL)** or Valgus (**MCL)** Stress tests (+) * **Swelling** over lig. ---- **Ecchymosis** * **​****Jt. Effusion IF _meniscal involve._** * \*\*\***Quadriceps dysf & Inhibition (Pain Related)** * Tenderness to **palpation of lig.** * **​**Attach's AND mid-substance * **Difficulty w/ _pivoting, cutting, etc.._** * **_​_**"I can run in a **straight line,** but my knee feels like it's going to fall apart **if I turn quickly"**

Question 60

ROM loss w/ ACL

Answer 60

Limited EXT \> FLEX

Question 61

ACL INJURY **S/S**

Answer 61

* **(+) Tests:** * **​**Lachman, Ant. Drawer, Pivot-shift * **Popping, Giving Way, Buckling** * **​**SEVERE pain w/ **jt effusion** * **Recurrent "giving way" episodes** * ​ADLs, Sports * Cont'd **effusion** * **QUAD INHIBITION\*\*\*\*** * **​**43% ACLD have **_quad activation failure_** * **_​_**Gen GREATER in **lg. effusions** * ​Quad strength+Time from injury NOT clinical predictors of AMI * **LIMTD ROM** * **​**Limtd EXT\>FLEX * **Flexed Knee Gait** * **​**ADDRESS IMMEDIATELY!!!

Question 62

PCL Injury ## Footnote **S/S**

Answer 62

* POST. **knee pain** * **Not as much** _effusion_ as **ACL** * **Flex beyond 90^o** may INC pain (in OPEN CHAIN) * Diff. **descending stairs**, **squatting, running** * NOT AS MUCH PROBLEM W/ **Quad Inhibition** * **(+) Tests:** * **​Sag sign, POST. Drawer,** REDUCED **palpation of tibial plateau step off** * **​**BC tibia sagging POST.

Question 63

These Lig. injuries MORE LIKELY TO CAUSE PAIN

Answer 63

MCL LCL

Question 64

Lig. Rehab ## Footnote **Symptom Modulation**

Answer 64

* Eliminate **effusion** * Restore **ROM** * **​Full HYPEREXT. NOW** * **Get past 90^o FLEX quickly** * **​**ESP **MCL** **injuries** * **Post. Tib. support for FLEX after PCL injury** * Soft Tissue Mobs * **Quad+HS strengthening** in pain-free ROMs * WB OR NWB * **Hip** strengthening * NO **ADD.** for **MCL injuries** * **​puts Valgus on knee** * NO **ABD.** for **LCL injuries** * **​puts Varus on knee** * **NORMALIZE GAIT!!!**

Question 65

Lig. Rehab ## Footnote **Motor Control** **(once things are calmed down)**

Answer 65

* MM **strength** * MM **length** * **WHOLE BODY** * **​**hips * HS's * CORE * Injury **_Prevention_** Tech's * balance * **landing** patterns * **Direction** changes

Question 66

Quadriceps Neutral Angle ## Footnote **\*Use for strengthening post-injury\***

Answer 66

* **Knee Flexion range** @ which tension in **quadriceps** does NOT **create ANT or POST _shear force_** * _​_**LESS THAN 60^O** produces **Ant. shear (60-0^o)** * **​90-60⁰ FLEX==**Safe for **ACL** * **GREATER THAN 75^O** produces **Post. shear** * **​0-60^o FLEX==**Safe for **PCL**

Question 67

Ligament Rehab ## Footnote **Functional Optimization** **\*Note "Functional"** **returning to "Function" or "prev. activity"**

Answer 67

* Running * **SIMPLEST form of DYNAMIC loading** * Agility+Plyo's * jump * hop * cut/pivot * **Sport-specific**

Question 68

Ligament Tear ## Footnote **Why should I WAIT?**

Answer 68

**PREHAB!!!** **\*\*\*\*"**Better IN, Better OUT"\*\*\*\*\* 1. **ROM** 1. **​Pre-OP ROM** predicts **Post-OP ROM** 2. **MM Function** 1. **​Pre-OP** **_Quad Strength_****==\>**SIG. predictor of**knee function after Sx** 2. NMES

Question 69

Neuromuscular Adaptations to Injury

Answer 69

* **Instability==HALLMARK Sx after ACL injury** * Now **inability to compensate** * Can result in **INCd injury** * **​**Now **poorer outcomes after ACLR** * Now **INCd risk of OA** * Altered **function** * **​**1. **Balance** * **​**altered control of **frontal plane Center of Pressure (CoP)** * 2. **Gait** * **Co-contraction of FLEXORS and EXTENSORS** * Truncated knee motion * Altered loading

Question 70

Potential Copers & Non-Copers ## Footnote **Fitzgerald et al. developed decision-making scheme for _returning to high lvl phys. act. following ACL tear and NON-OP Tx_** **Screening Exam?**

Answer 70

* **Screening Exam:** * **​**Single, Triple, Cross-over, **Timed 6m hop test (see pic)** * **​**80% or higher vs. uninvolved leg * Global rating of knee function * 60% or higher * Knee Outcome Survey ADL Scale * 80% or higher * Report the # of knee **giving-way** episodes from **time of injury to time of testing** * **​**NO MORE than **one event** of **tibiofemoral buckling or sublux.**

Question 71

Differential Responses to Injury

Answer 71

* **Gross co-contraction==crude method of** **_stabilization_** * _​_INCs **compressive forces** * INCs **degen.**

Question 72

**Fitzgerald et. al.** **Decision-making scheme for returning pts to high-lvl act. w/ NON-OP Tx after ACL** **_Rupture_**

Answer 72

* 93% pts w/ unilat. ACL ruptures * 28 met criteria + attempted NON-OP Tx * 22 (79%) **able to return pre-injury lvls of act. W/OUT recurring episodes of "giving-way" or extending the knee injury** **\*\*\*\*\*PERTURBATION TRAINING\*\*\*\*\*\***

Question 73

Return to sport for ACL====

Answer 73

9mos or longer

Question 74

Copers vs. Non-Copers

Answer 74

* Patients who are considered **copers** are individuals who are able to perform functional activities despite an ACL rupture. * **Non-copers** are patients who are unable to perform functional activities and have repetitive episodes of the knee “giving-way” (also known as instability). * These **non-copers** are less likely candidates for non-operative treatment.

Question 75

Perturbation Training ## Footnote **Explain associatin w/ ACL Rupture**

Answer 75

* **TEN SESSIONS USED:** * Improves **return to sport** after injury **w/out reconstruction** * DECs **co-contraction** and **resolves gait asymmetries** * **​Pre-operatively** in potential **copers** * can perform functional acts despite ACL rupture * **Post-operatively** in **non-copers** * unable to perform functional acts---more "giving-way"----less likely candidates for non-op Tx

Question 76

Clinical Course of Care **involving Perturbation Training**

Answer 76

see pics

Question 77

Pair matched comparison of Return to Pivoting Sports @ 1 year in ACL injured pts after NON-OP vs. OP Tx course ## Footnote **69 matched pairs, 1 yr after injury OR Sx** **OP vs. Non-OP**

Answer 77

**Among non-OP treated pts, those participating in _Lvl II sports_** **were MORE LIKELY to return to sport than those participating in _Lvl I sports_**

Question 78

Tx for Acute ACL tear: 5 yr outcome of randomised trial **RCT of EARLY ACLR and OPTIONAL Delayed ACLR**

Answer 78

* NO _statistically significant differences in:_ * **_​_****Pt reported outcomes** * **Radiographic OA** * **Act. lvl** **VERY INTERESTING!!!!!!!!!!!!**