Lecture 11: Tarsus, Metatarsus, & Phalanges (Exam 2) Flashcards
What is a plantigrade stance
When the foot is positioned so the plantar surface of the calcaneus contact ground
What is valgus position
An outward deviation
What is a varus position
An inward deviation
T/F: Tarsal fractures are rare in animals
True
Why are tarsal fractures ofte disabling
b/c the tarsal joints serve a major weight bearing function
What can happen if tarsal fractures are not treated
- Joint incongruity
- Dev of osteoarthritis
- Severe lameness
Who is fractures of the tarsus commonly seen in
Working breed dogs
What causes a calcaneal fractures
- Distracted by pull of the gastrocnemius m.
- Prevents bone contact btw/ fragments & interferes w/ healing
Who are fractures of the central tarsal bone commonly seen in
Racing greyhounds
How are fractures of the central tarsal bone repaired
W/ one or more small lag screw
What will be seen in a PE of a px w/ acute fractures of the tarsus
When they attempt to place wt. on the limb it will cause the tarsus to collapse in plantigrade stance
What diagnostic imaging should be done
- Req sedation or general ax
- Dorsoplantar, medial lateral & oblique projections
How are calcaneal fractures differentiated from lacerations/ruptures of the achilles tendon
- Laceration/rupture: Open wound & soft tissue swelling around the area proximal to the calcaneal tuberosity
- Fracture: Swell caudal to tarsus & crepitation elicited on palpation
What is the surgical tx for calcaneal fractures
Pull of the gastrocnemius muscle resisted w/ tension band wire, lag screws, or plates
What is the surgical tx for articular fractures of the talus
Anatomically reduced & rigidly stabilized for optimal outcome
What if tarsal fracture repair is not feasible
Arthrodesis of the tarsocrural joint is considered
Describe the calcaneus
- Largest of the tarsal bones
- The tuber calcaneus forms prominence for insertion of the achilles tendon
Describe the talus
- Second largest of the tarsal bones
- Side of the trochlea articulate w/ the medial & lateral malleoli
What is occurring in these pictures
Stabilization of a calcaneal fracture
How are transverse calcaneal fracture
W/ a tension band or wire plate
How are oblique or slab fracture stabilized
W/ lag screws
What is occurring in these pictures
Stabilization of a talus fracture
How are talus articular surface fractures stabilized
W/ diverging K-wires or lag screws
How is the neck of the talus stabilized
- Lag screw angled from caudal medial surface of the head of the talus into the trochlea or the talus (A)
OR
- A screw is placed from caudal medial base of the talus into the calcaneus (B & C)W
hat is the most important post op care for most dogs
Coaptation w/ a splint for up to 6 weeks
What can occur w/ pins for tension band stabilization of the calcaneal fracture
- May irritate soft tissue
- Can be removed after healing if needed
When are screws from reconstruction of the talus removed
They are not removed unless they cause a problem
What are some complications of tarsal sx
- Degenerative joint disease may occur after articular fractures & may be severe
- Delayed union or nonunion if the calcaneal fracture is not adequately stabilized
How do metatarsal bone fractures occur
From direct blow or force to paw or hyperextension injuries
Who is complete metatarsal fractures commonly seen in? What causes it?
- Grey hounds
- Can be b/c of fatigue or the normal bone has been loaded beyond its yield strain
Where are metatarsal fractures located
- The base (proximal end of the bone)
- The head (Distal end of the bone)
What is done for metatarsal, phalangeal fractures & luxations
- Early surgical repair (better results that closed reduction & splintage)
- Depends heavily on conditions
- Splinting may be necessary
What can chronic instability lead to
- DJD
- Less optimal function
Where do MC/MT avulsion fractures mostly occur
Most often on the 2nd & 5th bones
Who are metacarpophalangeal joints or interphalangeal joints most commonly seen in
- Working dogs
- Racing greyhounds
What diagnostic imaging should be done for MC/MT fractures
- Dorsoplantar & mediolateral views from the tarsus to ends of the digits
- Oblique view w/ the digits spread
- Lateral view w/ the affected digit pulled cranially
What medical management can be used for MT fractures
- Conservative treatment w/ fiberglass bivalve cast or metasplint (For closed nondisplaced metatarsal diaphyseal fractures of 1 or 2 bones)
- Coaptation
Describe coaptation medical management for MT fractures
- Cats w/ comminuted nonreducible fractures
- Most phalangeal fractures & acute sesamoid bone fractures
When are cast or splints removed
- Not removed until there is radiographic evidence of the fracture bridged w/ bone
- Usually 4 to 8 W
When is sx tx done for metatarsal fractures
- In athletic or racing dogs for optimal return to racing
- Plates & screws are used
When is plate fixation done
When FAS is low or when athletic function is desired
What type of plate fixation can be used on MT/MC fractures
- Bridging plate used to span & support comminuted fractures (digit 2)
- Compression plates applied to transverse fracture (digit 3 & 4)
- Lag screw compression is used for oblique fracture lines protected by neutralization plates (digit 5)
What is done for large avulsed fragments (from the base of the second & 5th MT)
- Req open reduction & internal fixation
- Ligamentous insertions cause fragment distraction
- Lag screws are used to counteract pull of adjacent ligaments or compress oblique fractures
What are the Tx considerations for MT/MC fractures
- Fractures of 1 or 2 bones w/ splint or cast (the unaffected bones form an internal splint to prevent deformity)
- Fractures of 3 or 4 bones txed w/ internal fixation
- Large displaced avulsion fractures are txed w/ lag screws
- Splint or bivalve cast applied after internal fixation until radiographic evidence of bone healing is achieved
When is the Intramedullary (IM) pinning tech done
Tx multi transverse or short oblique fractures in px w/ high FAS
Describe fractures of the phalanges
- Less frequent
- Most often amendable to splinting
Who is acute phalangeal luxations commonly seen in
Working or racing dogs
How are acute phalangeal luxations txed
W/ open reduction or suturing of the joint capsule & collateral lig
How is chronic luxations of the 2nd or 5th toe txed
Amputation
What is the result of arthrodesis of the metatarsophalangeal & interphalangeal joints
- Good function
- Pain relief
What fixation systems can be used for MT & phalangeal fractures
- Ortho wire
- IM pins
- External fixation
- Plates & screws
What determines the which fixation method is used
- Fracture Assessment Score
- Fracture location
Which MT phalangeal fracture implants can be used for a FAS of 0 to 3
- Bridging plates
- External fixators
- Lag screws for avulsion fractures
Which MT phalangeal fracture implants can be used for a FAS of 4 to 7
- Bone plates & screws
- IM pins
- Lag screws for avulsion fractures
Which MT phalangeal fracture implants can be used for a FAS of 8 to 10
- Splint or cast
- IM pins
- Tension band wire for avulsion fractures
How can MT fractures be externally fixated
- Connect the fixation pins w/ acrylic bars to provide rigid stabilization of comminuted fractures (A)
OR
- Place pins in Type Ib configuration & connect w/ acrylic (B)
