Download The Knee

Unit 5: Understanding
Athletic-Related Injuries to the
Lower Extremity
The Knee: Anatomy and Injuries
Sports Medicine
Mr. Smith
Mechanics of the Knee
• Hinge Joint
• Knee movement
–
–
–
–
Flexion
Extension
Slight Rotation
Gliding
• Knee stability
depends on
ligaments, joint
capsule, and muscles.
Joint Capsule
• Medial and lateral
•
•
•
condyles
Medial condyle is
longer than the lateral
condyle.
Trochlea – groove
that receives the
patella.
Articular cartilage
• Tibial plateau
• Tibial plateau has two
•
•
shallow concavities
(facets) that articulate
with the medial and
lateral condyles.
Tibial tuberosity
Main weight bearing bone
(95 – 97%).
• Largest sesamoid
•
•
bone in the body.
Articulates in the
groove between the
femoral condyles.
Provides a better line
of pull for the
quadricep muscles.
• Lateral collateral
•
•
•
ligament and muscle
attachment.
Non – Weight bearing
bone.
Located on lateral
aspect.
Minimal knee
function.
• Femur and tibia
• Femur and patella
• Tibia and fibula
• Attachment: femur –
•
•
intersurface of lateral
condyle.
Attachment: Tibia –
Anterior tibial
plateau.
Prevents excessive
anterior movement
and internal rotation
of the tibia.
•
•
•
•
Extension / Tight
Flexion / Relaxed
Very vascular
Usually surgically
replaced if torn.
• Attachment: Femur -
•
•
•
Anterior portion of the
lateral surface of the
medial condyle.
Tibia – Posterior medial
tibial plateau.
Prevents excessive
posterior movement of
the tibia on the femur.
Prevents hyperextension
of the knee
• Attachment: Femur –
•
•
superior epicondyle.
Tibia – Medial aspect /
medial meniscus.
Resists valgus forces.
• Resists external rotation
of the tibia.
• Attachment: Femur –
•
•
•
lateral epicondyle.
Fibula: Fibular head
Extracapsular
Resists varus forces.
• Aided by popliteal muscle
/ IT-band
• Medial (C- shape) and
•
•
•
•
•
lateral (O-shape)
meniscus.
Located on tibial plateau.
Primary function – shock
absorber.
Deepens articular facets
Increase surface contact.
Helps stabilize knee
• 3 vascular zones
– Red – Red Zone- outer
1/3 which has good
blood supply.
– Red – White Zonemiddle 1/3 which has
minimal blood supply.
– White – White Zoneinner 1/3 which is
avascular (no blood
supply)
• Bursa’s are fluid filled
•
•
•
sac’s .
Reduce friction between
anatomical structures.
Two dozen bursa’s within
the knee.
Prepatellar most often
injured.
• Extensors of the knee.
• Stabilizers of the knee.
• Vastus medialis (VMO) –
•
•
•
important for patellar
tracking.
Vastus intermedialis
Vastus Lateralis
Rectus femoris – Knee
extension / Hip flexion.
• Patellar Tendon –
•
•
Common tendon for
the quadriceps
muscle group.
Attachment: Tibial
tuberosity.
Houses the patella.
• Flexors of the knee.
• Extensors of the hip.
• Prevents anterior
tibial movement /
Aids ACL.
• Gracilis – Aids in knee
•
•
flexion.
Sartorius – Aids in
knee flexion / longest
muscle in the body.
Gastrocnemius – Aids
in knee flexion /
primary ankle plantar
flexor.
• Lateral side of knee.
• Assist LCL in the
lateral stability of the
knee.
• Mechanism –
•
Compression and
rotation femur / tibia.
Can be associated
with ligament injury
(MCL).
Signs & Symptoms
- Joint effusion
(Swelling)
- Clicking or locking.
- Loss of ROM
- Diagnosis is often
difficult.
Meniscus MRI
Meniscus Tear
• Surgical treatment
- Procedure depends
on location and
severity of tear.
- Resection (Total
removal of tear)
- Stitch or tack.
- Indicated only for
minor tears.
- RICE (Control
Swelling)
- Maintain ROM /
Strength
- Non surgical treatment
can result in further
damage
Arthriis
• Common in sports.
• Mechanism – External
•
rotation of tibia, knee in
valgus position, foot
fixed.
Signs & Symptoms
–
–
–
–
Feeling pop
Knee feels unstable
Joint effusion
Positive testing
• RICE (Control
•
•
•
Swelling)
Immobilizer /
Crutches
Refer to physician
Rehabilitation
(Strengthening &
ROM)
MRI of ACL
NORMAL ACL
ACL TEAR
• Arthroscopic
•
surgery
Various grafts can
be used for repair.
– Patellar tendon
(Autograft)
– Hamstring
(semitendinosus /
Gracillis)
– Cadaver (Allograft)
Patellar Tendon
(autograft)
• Injured less frequent
• Mechanism:
- Fall on anterior
aspect of bent knee
with foot plantar
flexed.
- Hyperextension
• Signs / Symptoms
- Experience “Pop”
- Effusion (swelling)
- Tenderness
posterior aspect of
knee
- Knee feels unstable
- Positive special test
MCL / LCL Injuries
• MCL injuries are usually caused by a
lateral to medial blow to the knee. Also
known as a valgus force.
• LCL injuries are usually caused by medial
to lateral blow to the knee. Also known as
a varus force.
• Mechanism of Injury
- direct blow from the
lateral side (Valgus
Stress)
- severe rotation of
the tibia
- can be a
combination of both
MRI OF MCL TEAR
• 1st degree
- ligamentous fibers are
stretched
- joint is stable during
valgus stress test
- little or no joint effusion
- may be some joint
stiffness and medial joint
line tenderness
- almost full range of
motion
• 2nd degree sprain
- partial tear of the
ligament
- slight to moderate laxity
during valgus stress test
- there is little joint
effusion
- moderate to severe
joint stiffness with loss of
ROM
• 3rd degree sprain
- Complete tear
- severe laxity
revealed with valgus
stress test
- moderate joint
effusion
- loss of ROM
• 1st degree – RICE,
•
•
Rehab to increase
strength, ROM.
2nd degree – RICE,
Immobilize, Crutch,
24 hours. Reevaluate. Refer to
physician
3rd degree – RICE,
Immobilize, Crutch.
Refer to physician
• Not very common in
•
athletics.
Occurs by a medial
blow to knee which
produces a varus
stress
Patellar Dislocation
Knee Dislocation
Assessing the
Knee Joint
HISTORY
– What did you feel, hear, …. Was there a pop
or snap?
– Did you get hit by another player? Was your
foot planted? Did this happen without being
hit?
– Exactly where does you knee hurt, and be
specific?
– Have you hurt this knee before, when, what
was the injury?
HISTORY
• When did you first notice the condition?
• Is there swelling or recurrent swelling?
• What activity hurts the most?
• Does it ever catch or lock?
• Do you fell as if the knee is going to give
way, or has it already done so?
• Does it hurt to go up and down stairs?
Observation
• Does the athlete have a limp, or is it easy
to walk?
• Cant the athlete be full weight bearing?
• Is the athlete able to perform a half-squat
to extension?
• Cant the athlete do up and down stairs?
Testing for Knee Joint Instability
• Testing helps one get a better idea of the
stability of the joint and an informed
decision can be made about playing
status.
• Many tests may point to ligamentous
damage, while others will help detect
meniscus damage.
• Knowing these test and how to perform
them takes practice and time to
understand the degrees of damage done
to the knee.
• Test for patellar
•
dislocations
Positive sign is
guarding, and
pain.
• Tests for torn meniscus
• Positive sign is popping,
•
clicking or pain.
Apley’s
Compression/Distraction
- Tests for torn meniscus
- Compression signs
same as McMurray
- Distraction sign is
reduction of pain.
Valgus and Varus Stress
Tests
• Purpose: intended to reveal laxity of the
medial and lateral collaterals.
• The athlete lie supine with the leg extended.
• Apply stress to the knee either medially or
laterally
Valgus Stress Tests
• The valgus examination in full extension
tests the MCL, posteromedial capsule, and
the cruciates. The exam at 30 degrees
flexion isolates the MCL.
• Tests for MCL
•
•
stability
Positive sign
indicates an injury
to the MCL
Test at 0 and 15
degrees
Varus Stress Tests
• The examiner reverses hand positions and
tests the lateral side with a varus force on
the fully extended knee and then with 30
degrees of flexion. With the knee
extended, the LCL and posterolateral
capsule are examined. At 30 degrees of
flexion, the LCL is isolated.
• Tests for LCL stability
• Positive sign indicates
•
an injury to the LCL
Test at 0 and 15
degrees
Anterior Cruciate Ligament
Tests
• Anterior Drawer Test
• Lachman’s Test
Anterior Drawer Test
• The tibia’s sliding forward from under the
femur is considered a positive anterior
drawer sign. If a positive anterior drawer
sign occurs, the test should be repeated
with the athlete’s leg rotated internally 30
degrees and externally 15 degrees.
• Anterior Drawer Test
- Tests for ACL
instability / laxity
• Positive sign is
increase in anterior
translation. (No end
point)
Anterior Cruciate Ligament
Tests
• Lachman’s Test: is considered to be a
better test than the drawer test at 90 degrees
of flexion.
Lachman’s Tests
• The Lachman’s test is administered by
positioning the knee in approximately 30
degrees of flexion. One hand of the
examiner stabilizes the leg by grasping the
distal end of the thigh, and the other hand
grasps the proximal aspect of the tibia and
attempts to move it anteriorly. A positive
Lachman’s test indicated damage to the
ACL
• Lachman Test
- Test for ACL
instbility/laxity
• Positive sign is
increased
anterior tibial
translation. (No
end point)
Posterior Cruciate Ligament
Tests
• Posterior Drawer Test: is performed
with the knee flexed at 90 degrees and
the foot in neutral position. Force is
exerted in a posterior direction at the
proximal tibial plateau. A positive
posterior drawer test indicates damage to
the posterior cruciate ligament.
• Posterior Drawer
- Test for PCL
instability/laxity
• Positive sign is
posterior
movement of the
tibia.
Posterior Cruciate Ligament
Tests
• Posterior Sag Test: With the athlete
supine, both knees are flexed to 9degrees. Observing laterally on the
injured side, the tibia will appear to sag
posteriorly when compared to the
opposite extremity if the posterior cruciate
ligament is damaged.
Prevention of Knee Injuries
• To avoid injuries to the knee, the athlete
must be as highly conditioned as possible,
which means total body conditioning that
includes strength, flexibility, cardiovascular
and muscle endurance, agility, speed and
balance.
• THE MUSCLES around the knee MUST be
strong and flexible.
Prevention of Knee Injuries
• Athletes participating in a particular sport
should acquire a strength ratio between the
quadriceps and hamstring muscle groups. Fro
example: the hamstring muscles of football
players should have 60 to 70 percent of the
strength of the quadriceps muscles. The
gastrocnemius muscle should also be
strengthened to help stabilize the knee.
Although maximizing muscle strength may
prevent some injuries, it fails to prevent
Prevention of Knee Injuries
• Shoe Type:
– Cleat Length
– Astro Turf shoes: more grip=more injuries
– Sneakers are good for artificial surfaces
Functional and Prophylactic
Knee Braces
• Functional Knee Braces are used to protect
grade 1 and 2 sprains of the ACL and MCL,
and reconstructed ACL knees. Most of them
are bilateral knee braces, meaning there is a
hinge on both sides of the brace. These
braces have an important part within the
athletic community. They will also give the
athlete confidence while playing.
Functional and Prophylactic
Knee Braces
• Prophylactic Knee Braces are designed to
prevent or reduce the severity of knee
injuries. They are worn on the lateral
surface of the knee to protect the medial
collateral ligament.
Knee Injury Treatments
• Straight Leg Raises
Knee Injury Treatments
• Side Leg Raises
Knee Injury Treatments
• Side Leg Raises
Knee Injury Treatments
• Terminal Knee Extensions
Knee Injury Treatments
• Step Ups
BOSU