The KNEE, FOOT & ANKLE
Dr. Shamay Ng
28 Jan 2019
Department of Rehabilitation Sciences
The Hong Kong Polytechnic University
Bones of Knee Joint
3 articulations:
•Two femoro-tibial
articulations
•One femoro-patellar
articulation
Moore et al. (2018): Fig 7.86 (8th edition)
Radiography of Knee Joint
Moore et al. (2018): Fig 7.87 (8th edition)
The Knee Joint
• Composed of three bones:
femur, tibia, patella
• Hinge-type condylar synovial
joint
• Movements allowed:
Flexion & extension
Rotation around vertical axis
(limited)
Femoro-tibial Joint
• 2 concave tibial plateaus
• Medial plateau is larger
surface area
• Covered with fibrocartilaginous
rings – menisci
 Medial meniscus:
semicircular
 Lateral meniscus: nearly a
complete ring
Menisci
• Medial
– Attachments:
 Peripherally – by coronary
ligament to tibial plateau
 Medially – attached to
capsule and MCL
 Anterior horn – transverse
ligament
Menisci
• Lateral
– Attachments:
 Peripherally – by
coronary ligament to
tibial plateau
 Anterior horn –
transverse ligament
Menisci
• Functions:
Shock absorbers
Improving congruency & contact area
During movement:
 Rotations: menisci move with femur
 Flexion/extension: menisci move with
tibia
•
Stability: Ligaments
Collaterals
– Medial
 Broad, fan-shaped ligament 10-12cm long
 Passes from medial epicondyle anteriorly to the
medial tibia
 Superficial and deep portions
Functions:
1. Resists excessive abduction of
tibia on femur
2. Limits anterior translation of
tibia on femur, and
hyperextension
•
Stability: Ligaments
Collaterals
– Lateral
 Fibrous cord 5-6cms
 Lateral epicondyle and directed
posterior to the fibular head
 No attachment of menisci
Functions:
1. Resists varus stress during flexion/extension
2. Limits knee hyperextension
Both collaterals help to limit external rotation of the tibia.
•
Stability: Ligaments
Anterior Cruciate
 Starts at anterior tibia
 Passes superiorly,
posteriorly and laterally
 Attaches to inner aspect of
lateral femoral condyle
(posteriorly)
Function:
 Prevents anterior translation of
tibia on femur
Stability: Ligaments
• Posterior Cruciate
 Starts at posterior intercondylar
tibia
 Passes superiorly, anteriorly, and
medially
 Attaches to inner aspect of medial
femoral condyle
Function:
 Resists posterior translation of the
tibia on femur
Both cruciates limit internal rotation of tibia on femur
Menisci and Ligaments
Patellar
surface
Ligaments that
Stabilize
the Knee Joint
Posterior cruciate
ligament
Anterior cruciate
ligament
Tibial collateral
ligament
Lateral
condyle
Menisci
Medial
Fibular collateral
ligament
Cut tendon of
biceps femoris
muscle
Medial
condyle
Tibia
Lateral
Fibula
Deep anterior view, flexed
Martini 10th Edition
Dynamic Movement: Muscles
• Extension:
Quadriceps femoris
• Flexion:
Hamstrings
• Special Function: Unlocking
Popliteus
Locking/Unlocking Mechanism
• The two condyles are not the same length in
the AP direction
• When reaching final extension (in OPEN
CHAIN) the lateral condyle ‘locks in’ to the
tibia first
• Then in order for the medial condyle to reach
the same position, tibia has to rotate laterally a
little bit
Both plateaus
moving together
Lateral condyle
locked in, so medial
plateau must
continue forward
Lateral rotation of
tibia in the last 20
degrees
Therefore, when in full extension = locked
To unlock, must medially rotate the tibia - popliteus muscle
accomplishes this
Capsule
• Common to both
tibiofemoral and
patellofemoral joints
• Surrounds joints like a
tube with a hole anteriorly
for patella
• Lax structure
• Statically stabilized by
ligamentous structures
• Dynamically stabilized by
muscle tendons
Quadriceps
tendon
Patella
Joint capsule
Synovial
membrane
Femur
Bursa
Fat pad
Joint cavity
Articular
cartilage
Accessory Structures
of a Knee Joint
Meniscus
Tibia
Ligaments
Extracapsular
ligament (patellar)
Intracapsular
ligament (cruciate)
Knee joint, sagittal section
Martini 10th Edition
Patellar Retinacula
• Fibrous expansions of the
vastus medialis and lateralis
muscles
• Retinacula extends distally
towards tibial plateaus &
posteriorly to collateral
ligaments
• Laterally, the retinaculum
contains expansion of the
ITB
Patellofemoral Joint
• Femur
– Anterior surfaces of femoral condyles and femoral sulcus
(intercondylar groove)
– Steep lateral condyle prevents lateral dislocation of patella
• Patella
‒ Medial and lateral
facets divided by a
vertical ridge
‒ Odd facet (most
medial aspect)
Patellofemoral Joint
• Stability
Longitudinally:
 Quadriceps tendon superiorly
 Patella tendon inferiorly
Transversely:
 Medial and lateral patellar
retinaculae (indirectly VM & VL)
Patellofemoral Joint
Movement:
 Full extension: no contact between
femur & patella
 10-90° of flexion both facets in
contact
 90-135° gradually less medial facet
contact until only lateral/odd
135°
Arterial Anastomoses Around Knee
• Genicular anastomosis
(genu=knee)
 Branches of femoral,
popliteal,
anterior/posterior tibial
arteries
Moore et al. (2018): Fig 7.53 (8th edition)
Popliteal Fossa
Moore et al. (2018): Fig 7.50 (8th edition)
Arteries of Leg and Foot
Moore et al. (2018): Fig 7.59 (8th edition)
Nerves of Leg and Foot
Moore et al. (2018): Fig 7.58 (8th edition)
Superficial Venous Drainage of Lower Limb
Femoral triangle
Long (Great) Saphenous vein
Popliteal fossa
Short (Small)
Saphenous vein
Ankle and Foot
Bones of the Foot
tarsal bones (7)
metatarsal bones (5)
Phalanges (14)
Moore et al. (2018): Fig 7.12 (A) (8th edition)
Tarsal Bones
Moore et al. (2018): Fig 7.12 (D & E) (8th edition)
Ankle joint
• Hinge type of synovial joint
• Proximal
– Distal ends of tibia + fibula +
inferior transverse part of the
posterior tibiofibular ligament
 mortise (deep socket)
• Distal
– Trochlea (L. pulley) of the
talus
Fibrous Capsule of Ankle joint
• Fibrous capsule
– Thin anteriorly and posteriorly
– Lateral collateral ligament
• Anterior talofibular ligament
• Posterior talofibular ligament
• Calcaneofibular ligaments
Moore et al. (2018): 7.99 (A) (8th edition)
Ankle joint
• Medial collateral ligament
 Deltoid ligament
Moore et al. (2018): Fig 7.100 (8th edition)
Talocrural (ankle) Joint
• Movements of the ankle joint
Dorsiflexion
Plantarflexion
Joints of Foot
•
•
•
•
•
•
•
•
Subtalar joint
Talocalcaneonavicular
Calcaneocuboid
Cuneonavicular
Tarsometatarsal
Intermetatarsal
Metatarso-phalangeal
Interphalangeal
Moore et al. (2018): Fig 7.101 (8th edition)
Transverse Tarsal Joints
Moore et al. (2018): Fig 7.12 (A & B) (8th edition)
Transverse Tarsal &
Subtalar Joints
• Transverse tarsal joint
 Calcaneocuboid and
talonavicular joints
• Subtalar joint
 Between talus and calcaneus
• Inversion and eversion
take place in these joints
Ligaments of the Foot
• Plantar calcaneonavicular
ligament (spring ligament)
 Connects sustentaculum
tali to the posteroinferior surface of the
navicular
Moore et al. (2018): Fig 7.103 (B) (8th edition)
Ligaments of the Foot
•Long plantar ligament
 From plantar surface of the calcaneus to
groove on the cuboid, bases of metatarsals
 Important in maintaining the arches of the
foot
• Plantar calcaneocuboid ligament
(short plantar ligament)
 Deep to the long plantar ligament
 From anterior aspect of the inferior surface
of the calcaneus to inferior surface of the
cuboid
Moore et al. (2018): Fig 7.103 (A & B) (8th edition)
Arteries of Foot
Moore et al. (2018): Fig. 7.75 (8th edition)
Nerves of Foot
Foot Arches & Weight-Bearing Areas of Foot
Moore et al. (2018): Fig. 7.104 (8th edition)
Transverse Arch
Metatarsals 1-5,
Cuneiform 1-3, Cuboid
Moore et al. (2018): Fig. 7.105 (A) (8th edition)
Longitudinal Arches
Medial:
MT 1-3, Cuneiform 1-3,
Navicular
Talus & Calcaneus
Lateral:
MT 4 -5, Cuboid &
Calcaneus
Moore et al. (2018): Fig. 7.105 (A & B) (8th edition)
Mechanisms of Arch Support
Shape of stones: “keystone”
Staples: ligaments
Tie beam: tendons
Suspension bridge: muscles
Example: Active and Passive Support of
Medial Longitudinal Support
Moore et al. (2018): Fig. 7.105 (C) (8th edition)
MUSCLES
4 Layers on the bottom of the foot:
1. Abductor digiti minimi, flexor digitorum
brevis, abductor hallucis
2. FHL, FDL, four lumbricals, quadratus
plantae
3. Flexor digiti minimi brevis, adductor
hallucis, flexor hallucis brevis
4. Plantar & dorsal interossei, tendons of
peroneus longus & tibialis posterior
Four Layers of Plantar Muscles
Moore et al. (2018): Fig. 7.71
(8th edition)
Nerves of Foot
• Adductor Hallucis*
• Quadratus Plantae
• Abductor digiti
minimi
• Lumbricals (2 lateral)
• Flexor Digiti Minimi
Brevis
• Interossei
Nerves of Foot
•Abductor Hallucis
•FDB
•Lumbricals (2 medial)
•Flexor Hallucis Brevis
Clinical Implications
Unhappy Triad of Knee Injuries
Moore et al. (2018): B7.34 (8th edition)
• TCL attach firmly to medial meniscus
• Tearing of TCL frequently results in
concomitant tearing of the medial meniscus
and ACL = “Unhappy triad”
Anterior & Posterior Drawer Sign
Anterior drawer sign
• Tibia slide anteriorly
under femur
• Tested via Lachman test
Posterior drawer sign
• Tibia slide posteriorly
under femur
Moore et al. (2018): B 7.34 (8th edition)
Ankle Sprain
• Mostly ankle inversion injury
• Twisting of the weight-
bearing, plantarflexed feet
• Lateral collateral ligament
(anterior talofibular
ligament) is most
commonly injured
Moore et al. (2018): B7.40 (8th edition)
Pott Fracture-Dislocation of Ankle
• Forcefully everted foot
• Pull strong on medial
ligament results in medial
malleolus fracture
• Break the fibula superior
to the tibiofibular
syndesmosis
Moore et al. (2018): B7.41 (8th edition)
Palpation of Dorsalis Pedis Pulse
• Lateral to the EHL tendons
• Absence of pulse suggests vascular insufficiency
resulting from arterial disease
Moore et al. (2018): B7.28 (8th edition)
Palpation of Posterior Tibial Pulse
• Between the posterior surface of the medial malleolus
and the medial border of the calcaneal tendon
Moore et al. (2018): B7.26 (8th edition)
Calcaneal Tendon Jerk
• Normal result: plantarflexion
• Tests the S1 and S2 nerve roots
Moore et al. (2018): B7.23 (8th edition)
Plantar Fasciitis
• Inflammation of the
plantar fascia
 Overuse from running
and high-impact
aerobics
 Inappropriate footwear
• Pain on the plantar
surface of the foot and
heel
Moore et al. (2018): B7.27 (8th edition)
Calcaneal Bursitis
• Inflammation of the
deep bursa of the
calcaneal tendon
• Pain posterior to the heel
• Caused by excessive
friction on the bursa as
the tendon continuously
slides over it
Moore et al. (2018): B7.24 (8th edition)
Hallux Valgus
L : Lateral deviation
By pressure from footwear and degenerative joint
disease
Moore et al. (2018): B.7.42 (8th edition)
Hammer Toe & Claw Toes
Hammer toe
• Proximal phalanx dorsiflexed at the metatarsophalangeal joint
• Middle phalanx plantarflexed at the proximal interphalanged joint
• Hyperextended distal phalanx
Claw toes
• Hyper extension of the metatarsophalanged joints
• Flexion of the distal interphalangeal joints of lateral 4 toes
Moore et al. (2018): B7.43 (A & B) (8th edition)
• Flexible:
Pes Planus (Flat Feet)
 flat when weight-bearing but normal when no weight
 More common, from degenerated intrinsic ligaments
• Rigid:
 flat with or without weight
Moore et al. (2018): B7.43 (C & D) (8th edition)
Injury of Common Fibular Nerve & Footdrop
• Toes fail to clear the ground
during the swing phase
• Causes:
 injury of the common fibular nerve
 Flaccid paralysis of all dorsiflexors
and evertors
Moore et al. (2018): B7.21 (8th edition)
Injury of Common Fibular Nerve & Footdrop
Compensations for “Footdrop”:
(D) Steppage gait
• Extra flexion at
hip and knee to
raise the foot
(B) Waddling gait
• Leans to the
side opposite
the long limb
(C) Swing-out gait
• Long limb abducted to allow
the toes to clear the ground
Moore et al. (2018): B7.21 (8th edition)
The End
Any Questions?