KNEE EVALUATIONS
Quick Facts
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Patellofemoral Joint (PFJ)
Variations in PFJ loading
during OKC and CKC
activities
PFJ loading increases:
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– with increased flexion in
CKC
– with increased extension in
OKC
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PFJ Loading
Walking
– 0.3 x body weight
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Ascending Stairs
– 2.5 x body weight
Descending Stairs
– 3.5 x body weight
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Squatting
– 7 x body weight
History
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MOI -
– Position of lower extremity at time of injury
extended)
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(?foot planted, knee
Previous history
Pain (levels, types, descriptors)
Unusual sounds/sensations “pop, clicking, snapping”
Chronic vs. acute
Location of pain “inside the knee”
Surface
Shoes
Type of activity at time of injury
Painful to walk up/down stairs; any clicking, catching
Did it swell immediately, slowly?
Is the swelling located in the knee or in a pocket?
Observation
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Bilateral comparison
Gait (limp, walking on toes, do they not want to
extend knee, do they keep the knee stiff)
Swelling (girth measurements)
Discoloration
Deformity (squinting patellae, “Frog-eyed”
patellae, Patella alta, Patella baja)
Genu valgum, genu varum, recurvatum
Musculature – defined/mushy
Q-angle
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The quadriceps angle
(Q-angle) is the angle
formed between a line
drawn through the
tibial tuberosity and the
center of the patella
and another line drawn
from the anterior
superior iliac spine
(ASIS) of the pelvis
through the center of
the patella.
Q-angle
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Knee in extension
– Normal males: 13 degrees
– Normal females: 18 degrees
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Knee in 90 degrees flexion
– Both genders: 8 degrees
Structural Alignment
Genu Varum (Bowlegged)
 Genu Valgum (knock kneed)
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Boney Palpation
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Tibia
– Tibial tuberosity
– Tibial Condyles (medial +
lateral)
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Pes Anserine
 Hamstrings
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– Semitendinosus tendon
– Semimebranosus
– Biceps femoris tendon
Fibula
– Head
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Medial joint line
Medial collateral ligament
Lateral joint line
Lateral Collateral Ligament
“Windows”
Medial & Lateral Femoral
Epicondyles
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Quadriceps muscle group
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Rectus Femoris
Vastus Lateralis
Vastus Intermedius
Vastus Medialis Oblique
Biceps femoris tendon
Iliotibial band
Popliteal fossa
 Gastrocnemius heads
 Patella
 Patellar tendon
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Boney Palpation
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Tibia
– Tibial tuberosity
– Tibial Condyles (medial + lateral)
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Fibula
– Head
Medial & Lateral Femoral Epicondyles
 Patella
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Surface Anatomy
Patella (A)
 Femur (B)
 Tibia (C,E –
tuberosity)
 Joint Line (D)
 Fibula (F)
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Boney Anatomy
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Bony Anatomy
– Lower Leg
 Tibia
– Bears most of the
weight
 Fibula
– Attachment place for
muscles & ligaments
– Upper Leg
 Femur
– Patella
Patella
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Sesamoid bone
Imbedded in quadriceps & patella tendon
Serves similar to a pulley for improving
angle of pull (results in greater mechanical
advantage in knee extension)
Tendons + Ligaments
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Medial joint line
Medial collateral ligament
Lateral joint line
Lateral Collateral Ligament
“Windows”
Pes Anserine
– Semitendinosus tendon
– Gracilis tendon
– Sartorius tendon
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Semimebranosus tendon
Biceps femoris tendon
Quadriceps Tendon
Biceps femoris tendon
Iliotibial band
Patellar tendon
Internal Knee Anatomy
Internal Knee Anatomy
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Medial
Meniscus
Lateral
Meniscus
Anterior
Cruciate
Ligament
Posterior
Cruciate
Ligament
Articular
Cartilage
Menisci
Bursae & Fat Pad of the Knee
Cruciate Ligament Movement
Anatomy – Soft Tissue
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Quadriceps –
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Rectus femoris
Vastus lateralis
Vastus intermedius
Vastus medialis oblique
Hamstrings –
– Biceps femoris
– Semitendinosus
– Semimembranosus
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Popliteus
– Popliteal fossa
Gastrocnemius +
Soleus
 Tibialis Anterior
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Muscles
Quick Facts
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Tibiofemoral Joint (TFJ)
Normal ROM
– Flexion 135-140 degrees
– Extension 0 degrees
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Closed Pack Position
– Full extension with ER
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Loose Packed Position
– 25 degrees of flexion
Knee Movements
Screw Home Mechanism
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Locking mechanism as the knee nears its final extension
degrees
– Automatic rotation of the tibia externally (approx. 10 degrees) during the
last 20 degrees of knee extension
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Femoral condyles are a different size
– Medial has larger surface area
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The tibia glides anteriorly on the femur. As knee extends, the
lateral femoral condyle expends its articular distance. The
medial articulation continues to glide, resulting in external
rotation of the tibia utilizing the lateral meniscus as the pivot
point.
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ACL & PCL are rotary guides
Special Tests
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Myotomes and Dermatomes
Valgus Stress test
Varus Stress Test
Tinel Test
Apley
McMurray
Anterior Drawer
Lachmans
Posterior Drawer
Godfrey’s 90/90
Posterior Sag
Patellar Apprehension Test
Clark’s Sign
Stress/Special Tests
Check for swelling
 Check ROM
 Check integrity of ligaments & joint
stability
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– Valgus, Varus, Lachman’s, Anterior/Posterior Drawer,
Godfrey’s 90-90 Test/Posterior Sag Test,
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Check integrity of meniscus
– McMurray’s, Apley’s Compression/Distraction, Duck Walk,
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Check integrity of patella
– Patellar Apprehension, Q Angle, Clarke’s Sign,
Special Tests
Anatomy of the ACL
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3 strands
Anterior medial tibia to
posterior lateral femur
Prevent anterior tibial
displacement on femur
Secondarily, prevents
hyperextension, varus &
valgus stresses
Biomechanics of the ACL
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Most injuries occur in Closed
Kinetic Chain
Least stress on ACL between
30-60 degrees of flexion
Anteromedial bundle tight
in flexion & extension
Posterior lateral bundle
tight only in extension
ACL Tears
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Most common mechanisms
– Contact:
 CKC with foot ER w/ valgus stress
 Hyperextension
 direct hit on the posterior tibia
– Non-Contact:
 Most common
 Due to sudden deceleration
 Sudden landing, cutting, or
pivoting
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Patient will c/o “buckling” or
“giving away”, typically will hear
and/or feel a “pop”
Diagnostic Imaging
Why perform an MRI after ACL injury?
Anterior Lachmans
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Position:
– Supine
– Knee flexed to 20 – 30 degrees
– Proximal hand on Femur above
the patella, distal hand on
Tibia just below Tibial
Tuberosity
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Action:
– Apply anterior force to the tibia
with the distal hand while
stabilizing the femur with the
proxmial hand
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Positive Findings:
– Anterior Cruciate Ligament
Sprain
 Joint opening up
Anterior Drawer
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Position:
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Action:
– Hip flexed to 45o; knee flexed @
90o
– Foot on table in neutral
– Examiner sits on foot w/ B
hands behind the subject’s
proximal tibia and thumbs on
the tibial plateau
– Apply anterior force to the
proximal tibia, feeling the
hamstrings for tightness
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Positive Findings
– Anterior Tibial Displacement
– Anterior Cruciate Ligament
Sprain
PCL Biomechanics
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Functions:
– Primary stabilizer of the
knee against posterior
movement of the tibia on
the femur
– Prevents flexion, extension,
and hyperextension
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Taut at 30 degrees of
flexion
– posterior lateral fibers
loose in early flexion
Posterior Cruciate Ligament
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Two bundles
– Anterolateral, taut in flexion
– Posteromedial, taut in extension
Orientation prevents posterior
motion of tibia
 PCL larger & stronger than ACL
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– CSA 120-150% larger
– CSA AL 2x PM
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Consider associated role of
posterolateral complex when
discussing PCL
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LCL
Popliteus Complex
Arcuate Ligament
Posterior Lateral Capsule
PCL Injuries
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Very rare in athletics, usually
due to MVA
– Due to hyperextension, hyperflexion, or the tibia being forced
posteriorly on the femur
– Only 33% related to sports
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Isolated PCL Injuries unusual
– Assess other ligaments
Avulsion Injuries
 Mid-Substance Tears
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Posterior Drawer Test
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Position:
– Hip flexed to 45o; knee flexed
@ 90o
– Foot on table in neutral
– Examiner sits on foot w/ B
hands behind the subject’s
proximal tibia and thumbs on
the tibial plateau
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Action:
– Apply posterior force to the
proximal tibia
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Positive Findings
– Posterior Tibial Displacement
– Posterior Cruciate Ligament
Sprain
Godfrey’s 90/90Test
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Position:
– Hip flexed to 90o; knee
flexed @ 90o
– Examiner holds onto both
heels
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Action:
– Look for posterior
translation of the tibia
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Positive Findings
– Displacement of the Tibia
– Posterior Cruciate Ligament
Sprain
Posterior Sag Test
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Position:
– Lie on table Knee flexed to
90o; Hip flexion 45o
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Action:
– Subject actively flexes Quads
while hip remains in 45o
– Look for a posterior translation
of the Tibia in relation to the
Femur
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Positive findings:
– Posterior Cruciate Ligament
Sprain
MCL Biomechanics
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Primary role is to prevent
against a valgus force
and external rotation of
the tibia
Throughout Full Range of
Motion:
– Both fibers are taut in full
extension
– Anterior fibers are taut in
flexion
– Posterior fibers are taut in
mid range
MCL Sprains
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Typically due to valgus forces in CKC
– Foot typically in neutral or externally rotated
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Most frequently injured ligament in the knee
Usually no joint effusion unless deep portion affected
since primarily located outside the joint capsule
Valgus Stress Test
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Position:
– Knee @ 0o and knee @ 30o
– Proximal hand on Lateral
joint line
– Distal hand on the lower leg
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Action:
– Apply medial force to lateral
joint line; and lateral force
to distal tibia
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Positive Findings
– Medial Collateral Ligament
Sprain
LCL Biomechanics
Primary role is to protect
from varus forces and
external rotation of the
tibia, assists in 2°
restraint for anterior and
posterior tibial translation
 Throughout Range of
motion:
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– Is taut during extension
– Loose during flexion
 Especially after 30° of flexion
LCL Sprains
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Typically due to varus forces, especially in CKC
position with leg adducted and tibia internally rotated
Usually occur during contact sports
Typically has limited joint effusion since it is located
outside of the joint capsule
Varus Stress Test
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Position:
– Knee @ 0o and knee @ 30o
– Medial hand on Medial joint
line
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Action:
– Apply lateral force to medial
joint line; and medial force to
distal tibia
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Positive Findings
– Lateral Collateral Ligament
Sprain
Meniscal Functions
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Deepens the articulation and
fills the gaps that normally
occur during the knee’s
articulation
Primary Functions
– Load distribution
– Joint Stability
– Shock Absorption
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Secondary Functions
– Joint Lubrication
– Articular Cartilage Nutrition
– Proprioceptive Feedback
Mechanism of Injury
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Trauma
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Compression
Rotational Force
Valgus Force
Usually Combination of Forces
Degenerative Changes
– Greater than 30 years old
– No PMHX required
– Often due to MOI that “seemed
harmless” at time
Noyes, 2002 states 60% of meniscal injuries associated with ACL injury
Apley
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Compression
– Position:
 Prone
 Knee flexed to 90o ; foot
dorsiflexed
– Action:
 Stabilize the femur with
examiner’s knee
 Push down on ankle/lower
leg and rotate
– Positive findings:
 Pain = Meniscus
 No Pain = Ligament
involvement
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Distraction
– Position:
 Prone
 Knee flexed to 90o ; foot
dorsiflexed
– Action:
 Stabilize the femur with
examiner’s knee
 Pull up on ankle/lower leg
and rotate
– Positive findings:
 No pain = Meniscus
 Pain = Ligament
involvement
McMurray
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Position:
– Supine
– Examiner’s standing with distal hand grasping the subject’s heel;
proximal hand on subject’s knee with fingers palpating the
medial and lateral joint lines
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Action:
– Knee fully flexed, externally rotate the tibia and introduce a
valgus force and extend the knee
 Medial Meniscus
– Repeat with internal rotation of the tibia and Varus force.
 Lateral Meniscus
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Positive Findings:
– “Clicking” indicates a Meniscal Tear
 Medial side = medial meniscus
 Lateral side = lateral meniscus
Unhappy Triad
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MCL, ACL, Medial Meniscus
Typically due to a valgus force
with the foot planted
PFJ Biomechanics
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During extension, patella
glides cranially
During flexion, patella
glides caudally
Patellar compression
– OKC greatest at end range
(final 30 degrees)
– increases in CKC after 30
degrees of flexion
Patellofemoral Pain Syndrome
 General
term to describe anterior
knee pain
 Caused by a variety of factors:
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Signs & Symptoms:
– Poorly localized Pain
– Little to no swelling
– Pt. Tenderness under lateral patella
– Insidious onset
Clark’s Sign (Patellar Grind Test)
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Position:
– Patient is lying supine w/ knee extended
– Examiner places the web space of the thumb on the
superior border of the patella
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Action:
– Subject contracts the Quads while the examiner
applies downward and inferior pressure to the patella
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Positive Finding:
– Pain with movement of patella or inability to complete
test
– Chondromalacia patella or patellar femoral syndrome
Patellar Apprehensive Test
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Position:
– Patient is supine and relaxed
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Action:
– Examiner grabs patella and pushes it in all 4 ways
 Superior / Inferior
 Lateral / Medial
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Positive Findings:
– Patient Apprehension
– Excessive Movement in one direction
– Dislocating Patella
Osgood-Schlatter’s Disease
Housemaid’s knee