Ankle and Foot Flashcards
What motion are the tib-fib joints important for?
DF and PF
Which tib fib joint has more motion?
Proximal
How much compressive force passes through the talus and tibia?
90-95%
Subtalar joint
Talus and Calcaneus
- Responsible for inversion/ eversion
- There are three articulations between these two bones (posterior, middle, anterior)
- Posterior articulation is 70% of surface area
Transverse tarsal joint
AKA midtarsal joint, Chopart’s joint
- Connects rearfoot with forefoot
- Very versatile
- Allows for adaptation to altering surfaces
- 2 joints: Talonavicular and Calcaneocuboid
Talonavicular Joint
- Medial component of transverse tarsal joint
- Convex talus, concave navicular
- Spring ligament
- Interosseous ligament
- Several other smaller ligaments
Spring Ligament
Spans from sustentaculum of the calcaneus to the medial-plantar surface of the navicular
- aka plantarcalcaneonavicular ligament
- little elastin - much collagen –> very taught
Maintains medial-longitudinal arch
Calcaneocuboid Joint
Lateral component of transverse tarsal joint
- Joint surfaces form an interlocking wedge that resists sliding
- Less motion than at the talonavicular joint
- Dorsal calcaneocuboid ligament, bifurcated ligament, long and short plantar ligaments
Distal Intertarsal Joints
Collection of 3 joints or joint complexes
- Cuneonavicular
- Cuboideonavicular
- Intercuneiform and cuneocuboid joint complex
Two functions
- Pronation/ supination
- Stability across the transverse arch of the foot
Tarsometatarsal Joints
AKA Lisfranc joint
- No measurable motion available
- Motion consists of gliding between segments
- Strong ligaments and joint congruence factors limit motion
Metatarsophalangeal joints
- Convex MT, cancave proximal phalanx
- PF (65) and DF (30-40) available
- ABD and ADD available in small amounts (use second digit as reference) - more apparent as compensation
First MTP Joint
- Flex: 45
- Ext: 70
Use 55 degrees extension in normal gait
Clinical significance: Hallux rigidus can lead to hallux valgus
Proximal Tibiofibular Osteokinematics
Important in DF Loose-pack position: Knee in mid range, ankle in 10 degrees PF Closed-pack position: Ankle in full DF Fibula glides: - Superiorly with DF - Inferiorly with PF
Distal Tibiofibular Joint
Ligaments:
- Interosseous lig
- Anterior inferior tibiofibular lig
- Posterior inferior tibiofibular lig
Loose-pack position: 10 degrees PF
Closed-pack position: Full DF
High ankle sprain
AKA syndesmosis sprain
- Disruption of tib fib ligaments and interosseous membrane
- Can occur with forced dorsiflexion and/ or eversion
- Rotational MOI
- Slow recovery
- Often associated with fx
- Significant laxity may require ORIF
Kleiger’s Test
High Ankle Sprain test
Talocrural Joint capsule
Thin, reinforced externally by ligaments
Talocrural Joint Ligaments
Deltoid complex (medial) Lateral collateral
Deltoid ligament complex
Anterior tibiotalar
Tibionavicular
Tibiocalcaneal
Posterior Tibiotalar
Fan shape
Very stout - stronger than lateral side (analog of MCL in knee)
Restricts eversion
Lateral Talar Tilt Test
AKA eversion stress test
Tests for MEDIAL/ DELTOID LIGAMENT integrity
Lateral ankle ligaments
Three components:
- Anterior talofibular
- Calcaneofibular
- Posterior talofibular
ATFL
- Lateral malleolus to lateral talus
- Weakest of ankle ligaments
- Most commonly sprained lateral ankle ligament (1st to tear)
Function: Resists motions of PF/ INV
Anterior Drawer test for ankle
Tests ATFL integrity
- Slight PF, perform anterior glide
- Look for increased laxity and suction sign anterior to lateral malleolus (sinus tarsi)
Calcaneofibular ligament
Function: resist motions of straight inversion
2nd ligament to tear with inversion sprain
Medial Talar Tilt test
Tests for CFL integrity
- AKA inversion stress test
Posterior Talofibular ligament (PTFL)
- Lateral malleolus to posterolateral talus
- Restricts DF/ INV
- Strong, usually only sprained after tear of ATFL and CFL (3rd degree sprains)
Talocrural Joint Arthrokinematics
OKC: Talus glides posteriorly with DF, anteriorly with PF
CKC: Tibia glides anteriorly with DF, posteriorly with PF
*Not entirely a sagittal plane movement
Talocrural Osteokinematics
DF: Mortise spreads, fibula migrates superiorly and posteriorly
PF: Fibula migrates inferiorly and anteriorly
DF: 15-25 degrees
PF: 40-55 degrees
Subtalar joint capsules
Posterior and ant/medial
Subtalar joint ligaments
- Medial, posterior, lateral talocalcaneal ligaments
- Reinforce posterior capsule - CFL
- Tibiocalcaneal (part of deltoid)
- Interosseous (talocalcaneal)
- Tarsal sinus
- Directly attaches talus and calcaneus
Arthrokinematics of Subtalar Joint
Considerable variation between individuals
3 sets of facets
Axis of rotation: Line that pierces lateral posterior heel and courses through STJ in ant, med, sup direction
Subtalar/ calcaneal inversion: 0-25
Subtalar/ calcaneal eversion: 0-15
Pronation
- Mobile position of foot
- ABD + Eversion + DF
Supination
- Stable position of foot
- ADD + Inversion + PF
Pronation is associated with… (tibia, knee, femur)
Tibial IR
Genu valgum
Femoral IR
Supination is associated with… (tibia, knee, femur)
Tibial ER
Genu varum
Femoral ER
Subtalar neutral
Podiatric theory suggesting that subtalar joints are “neutral” (neither pronated nor supinated) in bilateral stance
Longitudinal axis of transverse tarsal joint –> what motion?
Inversion and eversion
aligns nearly with AP axis
Oblique axis of transverse tarsal joint –> what motion?
ABD/ADD and DF/PF
What happens to the two axes of rotation of transverse tarsal joint in supination?
Axes cross –> Midfoot locks up
Lisfranc ligament
2nd cuneiform –> 2MT (plantar surface)
MTP Extension does what to medial longitudinal arch?
Tension in medial longitudinal arch
Where are the sesamoid bones in the first MTP?
FHB tendons