Diseases of the carpus and tarsus Flashcards
Which side is medial and which is lateral?
Which side is medial and which is lateral?
What is the difference between a short collateral ligament and a long collateral ligament?
- Short portion
- Taut in both flexion and extension
- Cross joint obliquely–> rotational stability
- Anatomically divided into 2 parts
- Connect adjacent bones only
- Do not bridge more than 1 joint
- Long portion
- Spans entire tarsus–tibia to metatarsals
- Taut in extension only
T/F: All ligaments in the carpus are short ligaments
TRUE
What is the typical etiology of collateral injuries?
Typically arise from HBC or other trauma
T/F: Collateral injuries can lead to permanent damage, so you should always treat them ASAP following any kind of trauma
FALSE
Always treat life-threatening trauma FIRST
T/F: You should always assess the thorax in major trauma
TRUE
T/F: Collateral injuries frequently occur on the medial side of the joint and have loss of both soft tissue and bone
TRUE
“Road rash”
How do you assess collateral injuries?
PE and rads
Which radiograph views are necessary and why?
- Standard dorsopalmar and lateral views
- Rule out fractures
- Stress radiographic views
- Necessary even when collateral injury is obvious
What is meant by “valgus stress” and “varus stress”?
- Valgus = Laterally deviates distal limb
- Varus = medialy deviates distal limb
What stress radiographic views are used to assess collateral injury?
- Dorsopalmar stress views
- Dorsopalmar views with valgus/varus stress
- Documents injury
- Wooden spoon can act as fulcrum
- Tape pulls distal limb medially or laterally
How will both valgus and varus stress affect the distal limb following a medial collateral injury?
- Valgus stress–pressure from the medial side moves the distal limb laterally
- Pressure opens the joint on the medial side due to MCL deficiency
- Varus stress–pressure from the lateral side moves the distal limb medially
- Pressure does NOT open the joint because the LCL is intact
What are the treatment options for collateral injury?
- Conservative management is rarely useful
- Splinting + rest unhelpful as sole treatment
- May be necessary if sx is delayed
- ESF in the presence of soft tissue trauma (instead of coaptation)
- Coaptation may be used, but not as sole treatment
-
Surgical treatment is preferred
- Reconstruct/replace collateral
- Salvage necessary with excessive trauma
How is collateral ligament replacement performed?
- Screw or bone tunnel in origin and insertion of each ligament
- NONabsorbable, large diameter suture placed in figure 8 pattern
- Take ligamet anatomy into account:
- Carpus: stimulate short ligament(s)
- Medial: straight, oblique (2)
- Lateral: straight only
- Tarsus: stimulate short AND long ligaments
- Carpus: stimulate short ligament(s)
What kind of suture is needed for collateral ligament replacement?
Large diameter, NON-absorbable suture
Ex: #2 (MUCH larger than 2-0)
What structures are damaged in hyperextension injuries?
- Palmar/plantar support ligaments
- Allows abnormal motion (hyperextension) between rows of tarsal/carpal bones
What do the terms “flexor retinaculum” and “palmar fibrocartilage” refer to?
- Flexor retinaculum encloses DDF tendon
- Palmar fibrocartilage extends from the distal aspect of the proximal carpal bones *radial, ulnar) to the proximal aspect of the metacarpals
What are the common etiologies of hyperextension injuries?
- Trauma
- Immune-mediated arthropathy
- Disease weakens palmar/plantar stabilizers
- Corticosteroids also tend to weaken ligaments
- Breed-related: middle-aged shelties/collies
- Chronic, progressive breakdown
- Genetic weakness suspected
- May be bilateral
Name/describe the joints of the carpus
- Antibrachiocarpal joint
- Between radius/ulna and proximal row
- Almost all motion occurs here
- Middle carpal joint
- Between 1st and 2nd rows
- Carpometacarpal joint
- Between 2nd row and metacarpal bones
Name/describe the joints of the tarsus
- Tarsocrural (tibiotarsal) joint
- Between tibia (crus) and talus
- Almost all motion occurs here
- Proximal intertarsal
- Calcaneoquartal–calcaneus and 4th tarsal
- Tarsometatarsal
How do you identify hyperextension injuries on a PE?
-
Hallmark: hyperextended stance
- Tarsus: dropped hock
- Tarsus touches but calcaneous tilted proximally
- Plantigrade stance: calcanean tuberosity touches
-
Dropped hock does NOT equal ‘plantigrade stance’
- Dropped hock = joint sitting lower than it should
- Plantigrade = heel touching ground
*
- Tarsus: dropped hock
How are radiographs used in hyperextension injuries?
- Standard views
- Rule out other injuries
- Provide basis for comparison
- Stress views
- Determine diagnosis
- Determine level of injury
- Use lateral views for hyperextension injury
- Stabilize limb proximal to carpus/tarsus
- Stimulate wt.-bearing to detect instability
Diagnosis?
Hyperextension of the carpus
T/F: Conservative management of hyperextension injuries is rarely useful
TRUE
Use prior to surgery only
Can coaptation be used as definitive treatment for hyperextension injuries?
NO
What is the preferred treatment for hyperextension injuries?
Surgery
Arthrodesis of affected joint + joints distal
Required for definitive treatment
What is partial carpal arthrodesis?
- Indicated if antebrachiocarpal joint is healthy
- Middle and carpometacarpal joints are fused using a T-plate or pins
- Function of carpus is almost unaffected–almost all motion at antebrachiocarpal joint
What is pancarpal arthrodesis?
- Antebrachiocarpal joint is abnormal
- All 3 joints fused
- DCP applied–specialized plates
- Dorsal application is typical
- Lateral application is described
T/F: The tibiotarsal joint is rarely injured by hyperextension
TRUE
What are the differences between arthrodesis of the calcaneoquartal and proximal intertarsal joint?
- Calcaneoquartal
- Lateral half of proximal intertarsal joint
- Lag screw or pin/tension band
- Applicable for most situations
- Proximal intertarsal
- Entire joint
- Lateral plate
Compare and contrast proximal intertarsal arthrodesis to tarsometatarsal arthrodesis
- Proximal intertarsal
- Partial tarsal arthrodesis
- Plate engages calcaneus
- No effect on tibiotarsal articulation
- Full ROM is maintained
- Tarsometatarsal
- Lateral plate
- Partial tarsal arthrodesis
- No effect on tibiotarsal articulation
- Full ROM is maintained
Diagnosis?
Proximal intertarsal hyperextension
What procedure was performed on this hyperextension injury?
Calcaneoquartal arthrodesis
Diagnosis?
Tarsometatarsal hyperextension
What post-op management is required following arthrodesis (regardless of location)?
- Coaptation
- 4-8wks
- Splint or external fixator
- Activity restriction until bony fusion
- Expect 3mo minimum
- Radiographs Q4wks to assess healing
- Explantation occasionally required
What is the signalment/presentation of carpal laxity syndrome?
- Young (5-27wks)
- Usually male (predisposed)
- Lots of breeds
How is carpal laxity syndrome recognized?
- Loose joint
- Hyperextension, hyperflexion, flexural deformity w/ palpable injury
What are the treatment recommendations for carpal laxiy syndrome?
- Spontaneous recovery in 1-4wks
- Diet (energy-restricted)
- Controlled exercise
- Flooring w/ good traction
What is the prognosis for carpal laxity syndrome?
Excellent
What are the components of the common calcanean tendon?
- Gastrocnemius tendons
- Combined tendons of the gracillis, semitendinosis, biceps femoris
- Tendon of the SDF
What is the difference in signalment between complete and partial rupture of the calcanean tendon?
- Complete: plantigrade stance
- Partial
- SDF usually preserved
- Partial hyperflexion
- Flexion of digits
What is the difference in history of complete and partial rupture of the calcanean tendon?
- Complete
- Acute
- Usually trauma
- Partial
- Chronic
- Minimal to no trauma
- Medium and large-breeds (lab, doberman)
- Older female cats
- Cause unknown (repetitive trauma suspected)
What is the procedure for calcanean tendon repair?
- Debride tendon ends
- Primary tendon repair
- 3-loop pulley > locking loop
- Immobilize tarsus in extension
- 6-8wks
What type of suture is indicated in tendon repair? Why?
Heavy, monofilament non-absorbable suture
The tendon has very poor blood suppy–need suture to last long enough for the tendon to heal (6-8wks)
T/F: Post-op coaptation is required following tendon repair
TRUE–cannot repair well enough for it to be weight-bearing while healing
External fixator, splint, or giant lag screw
What is the prognosis for tendon rupture following treatment?
- Generally good
- Most (>75%) dogs and cats return to fx
- Working dogs more guarded
- Immobilizing post-op is VERY important
- Complications related to coaptation method
What is the breed susceptibility for OCD of the hock?
Rotweilers predisposed
Same breeds as with OCD anywhere
T/F: OCD of the hock is frequently unilateral
FALSE–frequently bilateral
Where on the hock does OCD usually occur?
Lesion is usually located on the medial ridge of the talus
(Rotweilers commonly have OCD on the lateral ridge)
What is the hock flexion test?
- Flex the limb and hold in hyperflexion and have the dog walk away–see if lameness is aggravated
- Only tells that there is a problem in the hock–will not diagnose OCD
How is OCD of the hock diagnosed?
Radiographs–articular flattening, lucency
What radiographic views are necessary for diagnosis of OCD in the hock?
- Standard lateral and craniocaudal views (might not see lesion)
- Flexed lateral–expose proximal talus
- Flexed craniocaudal–cranial trochlear ridges
What are the treatment options for OCD of the hock?
- Medical therapy–older dog, established OA
- Surgery
- Fragment excision/debridement
- Young dog, no OA
- Heals w/ fibrocartilage
- Arthroscopy vs. arthrotomy
- Tibiotarsal (aka tarsocrural) arthrodesis
- Fragment excision/debridement
What is the prognosis for OCD of the hock?
- Guarded to poor
- Sx intervention
- Arthrotomy and fragment removal may be no better than medical management
- Arthroscopy = ideal
- Sx doesn’t prevent development of OA
- Current wisdom
- Sx improves function somewhat
- Does not eliminate lameness
What are the indications for tarsocrural arthrodesis?
- Fractures–comminuted articular
- Luxation–persistent instability
- Failed collateral injury repair
- Failed partial arthrodesis
- Failed calcanean tendon repair
- OA not responsive to medical management
- End-stage OCD
- Previous trauma
Explain the tarsocrural arthrodesis procedure using the basic principles
- Fuse tibiotarsal joint at standing angle
- Remove articular cartilage
- Sagittal saw–distal tibia/proximal talus
- Burr-small joints
- Pack with bone graft
- Rigid fixation
- Plate–dorsal, lateral, or medial
- Type 2 external skeleton fixator
What is the expected long-term outcom for pantarsal arthrodesis?
- Loss of hock ROM
- Mechanical lameness
- Most dogs have acceptable function
- Pet: good
- Working dog: guarded to poor
