Lecture 6 Flashcards
(26 cards)
What’re the names of the bony arches of the foot and what’re they’re functions?
Transverse and longitudinal
Give dynamic support by muscles and tendons in which they absorb forces that are transmitted during walking, marching, running, hopping, jumping, etc. (these are common reasons for injuries that led to the formation of Ottawa ankle and foot rules)
Explain the Ottawa rules for foot radiography
X-ray required if pain on midfoot or
- navicular bone
- base of 5th MT
- inability to right bear immediately or in ER
Ankle or foot injury the rules are Sensitive for ages 3-5 but if there’s ankle and midfoot injury it’s sensitive for ages 5-55
What’re the divisions of the foot and what bones do they comprise of?
Hindfoot = calcanous and talus
—x- separated by talonavicualr and calcaneocuboid joint (chopart)
Midfoot= cuboid and cuneiforms
—-seperated by tarsometatarsal joint (lisfranc joint)
Forefoot = MT and phalanges
Then we have our sub talar joint (joint between talus and calcanous)
What’s the function of the lisfranc joint and how is it injured?
Provides stability to midfoot and there is minimal movement at joint. Base of MT 2 is key for the stability of this joint
Injury due to direct crushing injury to dorsum midfoot or indirect axial force applied to plantar flexed with slight rotation with forced abduction or twisting
What’s the function of the chopart joint and how is it injured?
Allows foot to adapt to uneven surface. Helps with the push effort (ie. while taking a step it helps lift the foot off the ground)
Injury due to fall from height, servers twisting when landed with plantar flexed foot and inverted
Name the relevant ligaments of the foot
ATF lig
PTF lig
Lateral collateral ligs
- Posterior talofibular
- calcaneofibular
- anterior talofibular
Whats a Jones frvature?
Frvature of shaft of 5th due to adduction of forefoot with ankle plantar flexed
But can be:
The avulsion of the apophysis from the attachment of the peroneus brevis tendon at the tuberosity at base of 5th due to inversion injury
Normally the apopphysis gives off a fractured appearance but it isn’t. It’s normally longitudinal, so a frvature will tend to be transverse
What’s a friebergs disease/infraction?
Osteochondritis of head of MT
The curvature of heads will be more flat
Explain what’re sesamoids of the foot and name them?
Theyre small piece of bone that is within a tendon and passes over a joint and enables better support of a distal part.
They’re derived from two ossification centres thus the medial ones are bipartite and will unite
Hallucal sesamoids = head of MT1 (take most of force)
- FOUND ON plantar aspect with medial sesamoids being bipartite (into two) and lateral one is in one (fracture of the bipartitite sesamoid tends to run along the long axis - can lead to sesamoiditis). They weightbear and elevate head off ground
Interphalangeal joint of halluc
Media aspect of heads MT 2-5
What’re accessory ossicles and name them?
They’re ossification centres that have detached from bone but are close to bone. Small and smooth borders
Don’t confuse them for sesamoid or apophysis
Os trigonum = posterior of talus
Os peroneum = plantar, near calcaneocuboid joint
Os naviculare= tuberosity of navicular
Os intermetarseum = between bases 1 and 2 MT
Os supranavicular = dorsum to talonavicular joint
Os supratalar = dorsum to neck of talus
What’s an apophysis?
A bony outgrowth from an ossification centre into attached tendon or ligament
Apophylitis- They can become inflamed due to stress injury to the attached muscle/tendon ie. plantar spur from calcaneous where plantar fascia inserts (plantar facilitis)
Why do we do weight bearing scans of the foot?
We do it to look for ligamentous support, and spaces between the metatarsals will increase in size , therefore, we do lateral and DP weight bearing to suspect malalignemnt.
Lateral = malalignemnt and foot pain DP = assess foot malalignemnt esp in metatarsals and tarsals (ie. lisfranc injury/fracture)
Explain what a lisfranc joint injury is
Uncommon, 3rd decade occurrence, hard to diagnose due to subtlety as initially scans look normal. It’s the disruption of tarsometatarsal ligs, and the lisfranc lig attaches the base of 2 MT with medial cuneiform (this can rupture or stretch)
Signs = pain on lisfranc joint when touched and when weight bearing, swollen foot, plantar midfoot bruising, instability midfoot
Usually due to fall or accident where the forefoot is fixed and the mid and hind foot atr forced plantarward and rotated
Ie. dancer falling while on their tippy toes
What’s a protocol for when there is suspected lisfranc fracture?
Weight bearing DP, oblique and weight bearing lateral, then we do CT
DP = medial edge of MT 2 should be in line with medial edge of medial cuneiform and medial edge of MT 4 should be in line with medial edge of cuboid. BASE MT 2 MOST IMPORTSNT (is there loss of alignment there)
Medial oblique = medial edge of MT 4 lining up with medial edge of cuboid
What’re the stages of lisfranc fracture?
Stage 1 = sprain of lisfranc lig
Stage 2 = ruptured lig with 2-5 mm spread of metatarsal, but no arch or height loss
Stage 3 = ruptured lisfranc lig with 2-5 mm diastasis (space) with loss of arch and height
Explain what’s a chopart joint injury
Severe foot injuries, poly trauma injuries
Uncommon fractures/dislocations, difficult to diagnose
Small avulsion from navicular and/or cuboid may be a strong indicator of severe injury to joint.
Can lead to forefoot and midfoot amputation as this chopart joint is very close to subtalar and lisfranc joints. Thus, often the injury involves other complications
Signs = abnormal positioning of forefoot to medial direction, swelling st dorsum, painful midtarsal region
What projections should be done when suspected chopart joint?
DP
OBL
LAT
CT OR MRI
So a combination of both chopart and lisfranc is classified as?
A crush injury
It falls into the category of crush injuries
Explain what a navicular stress fracture is
Force being transmitted through navicular, into the talus and up the leg
Usually you’ll see the navicular being split as a result of the reprove microtrauma to the bone. Usually see a frvature splitting down the centre.
When we ask if there’s pain on navicular in the rules
Most easily seen in MRI (bone textology)
What regions of the foot are suspected for stress fractures?
Calcneous, navicular and metatarsals (refer to OF rules)
Signs = pain on dorsum, tenderness on injury site, pain during physical activity but fine during normal
What other forms of navicular injury can occur?
Kohler’s disease
Which is the osteochondritis of the navicular, usually occurs in children
Causes decreased navicular size (looks like a flat disc), fragmented and sclerotic
Head of talus is slightly flattened
Therefore! It will cause pathological fractures in most instances
Explain the occurrence of calcaneal fractures
Sinus tarsi becomes narrow and quite dominant ie. loss of Kagers triangle . Loss Articulation of the culcaneocuboid joint
Or
Achilles’ tendon contracted creating a beaks fracture
- immediate surgery required especially if fracture extends into the posterior facet of the calcaneous due to short saphenous vein and Sural nerve being impaired
How can you analyse a calcaneal injury/fracture using Bohlers angle?
Angle formed between a line drawn from posterior aspect of superior cacaneus and another line drawn from anterior aspect of superior calcaneous
The angle should be around 20-40 deg for it to be normal
How can you analyse a calcaneal injury/fracture using the critical angle of gissane?
Angle formed between line drawn from medal posterior facet of calcaneous and another line drawn down dorsal surface of calcaneal neck
Normal range = 120-145 deg with an average being 100
