Sx Diseases of the Carpus and Tarsus Flashcards
How can you tell the lateral and medial sides of the carpus and tarsus
from a radiograph?
Carpus: Ulnar carpal bone is lateral
Tarsus: Trochlea of the talus is medial (the bone itself looks like an “m”)
Describe the collateral ligaments in the carpus
All carpal ligaments are short ligaments
Radial collaterals: straight and oblique parts
Ulnar collateral: straight part only
Describe the collateral ligaments in the tarsus
Both short and long portions for the medial and lateral collaterals
Long portion: Taut in extension only (taut when the limb is long)
Short portion: Taut in both extension and flexion (cross obliquely for rotational stability)
What’s the difference between a short and long ligament?
Short ligaments connect adjacent bones only and
do not bridge more than one joint
What is the typical etiology of collateral injury?
HBC trauma
Which collateral injuries are most common?
Medial
Why do shear injuries commonly accompany collateral injuries?
Due to the conformation of the collaterals, trauma results in shearing force
Why do collateral injuries tend to occur on the medial side of the joint?
It’s easier for the distal limbs to move in the VALGUS (lateral)
direction, putting more stress on the medial collateral components
What radiographic views are necessary for diagnosing collateral injury?
Dorsopalmar stress views
What is valgus stress, and how is it different from varus stress?
VaLgus stress = Laterally deviates distal limb
Varus stress = Medially deviates distal limb
What type of stress is applied to identify damage to the medial collateral ligament?
VaLgus stress (or pressure from the medial side) moves the limb laterally
and opens the joint on the medial side due to MCL deficiency
What type of stress is applied to identify damage to the lateral collateral ligament?
Varus stress (or pressure from the lateral side)
moves the limb medially
and opens the joint on the lateral side due to LCL deficiency
T/F:
Conservative treatment should be pursued first in collateral ligament injuries
FALSE! Conservative tx rarely helpful! Need surgery!
What kind of coaptation can be used in collateral ligament injury
(not as a definitive tx though)?
Splinting
ESF used in the presence of severe soft tissue trauma (SHEAR)
In broad terms, how is collateral ligament replacement performed?
Bone tunnel or screw with
heavy NONabsorbable suture placed (figure-8 pattern) between them
Prosthetic ligaments with screws placed at the origin and insertion of the original ligament (proximal and distal to the joint)
If in the tarsus, BOTH short and long ligaments must be replaced
what structure(s) are damaged in hyperextension injuries?
Palmar/plantar support ligaments
What do “flexor retinaculum” and “palmar fibrocartilage” refer to?
Both refer to the superficial palmar ligaments
Flexor retinaculum: encloses the DDF tendon
Palmar fibrocartilage: extends from the distal aspect of the proximal carpal bones to the proximal aspect of the metacarpals
What are the common etiologies of hyperextension injury?
Trauma
Immune-mediated arthropathy (contributes to b/d of palmar/plantar ligaments)
Corticosteroids
What breeds have a genetic predisposition to bilateral disease
(breakdown of palmar/plantar ligaments in regards to hyperextension injury)
Middle-aged Shelties and Collies
What are the 4 joints of the carpus?
- Hinge joint (Ginglymus)
- Antebrachiocarpal joint
- between radius/ulna and proximal row of carpal bones
- Almost all motion occurs here
- Middle carpal joint
- Between first and second rows of carpal bones
- Carpometacarpal joint
- Between second row of carpal bones and the metacarpals
What are the 5 joints of the tarsus?
- Hinge joint (Ginglymus)
- Tibiotarsal (Talocrural) joint
- Between tibia (crus) and talus
- Almost all motion occurs here
- Proximal intertarsal joint
- Calcaneoquartel joint
- Between the calcaneus and the 4th tarsal bone
- Tarsometatarsal joint
- Between the tarsal bones and metatarsal bones
- Calcaneoquartel joint
How do you identify hyperextension injuries on a physical exam?
Swollen painful joint with hallmark hyperextended stance (dropped hock)
What kinds of radiographs are used in hyperextension injuries?
Standard dorsopalmar/plantar view and lateral view - r/o fractures and provide basis for comparison
Stress views (lateral) - determine level of injury
How is stress applied to identify hyperextension injuries
on radiographs?
Stabilize limb proximal to the carpus/tarsus
then stimulate weightbearing to detect instability
What are the treatment options for hyperextension injury?
Conservative management NOT USEFUL (but splinting prior to sx)
Arthrodesis (of affected joint and joints distal) is required for definitive tx
What is the difference between partial and pancarpal arthrodesis
in regards to hyperextension injury?
-
Partial Carpal Arthrodesis
- Indicated if: antebrachiocarpal joint is normal
- Joints fused: Middle and carpometacarpal joints
- Using T-plate or pins
- Function of carpus after: Unaffected
-
Pancarpal Arthrodesis
- Indicated if: antebrachiocarpal joint is abnormal
- Joints fused: ALL! (Antebrachiocarpal, middle, carpometacarpal)
- Using DCP specialized plates
What are the options for arthrodesis of the tarsus for hyperextension injury and what are the differences between the 2 options?
-
Partial Tarsus Arthrodesis
- For proximal intertarsal hyperextension injury
- Joints fused: calcaneoquartel (lateral half)
- Using lag screw or pin/tension band
- Joints fused: calcaneoquartel (lateral half)
- For tarsometatarsal hyperextension injury
- Joints fused: tarsometatarsal
- Using laterally applied plate
- Joints fused: tarsometatarsal
- For proximal intertarsal hyperextension injury
-
Pantarsal Arthrodesis (RARE)
- For tibiotarsal joint hyperextension
- Joint flexes in direction of the injury, rare to be injured this way
- Other tarsals/carpals do not flex this way
- For tibiotarsal joint hyperextension
What are the post-op procedures after arthrodesis of the carpus?
Coaptation (splint or ESF) - 4 to 8 weeks
Activity Restriction - about 3 months
Radiographs every month to assess healing
T/F:
Healing of arthrodesis is prolonged compared to that of a fracture
TRUE
What is the signalment and presentation of carpal laxity syndrome?
1 to 7 months old
Male dogs
PE reveals: Both hyperextension and hyperflexion
What are the treatment recommendations for Carpal Laxity Syndrome?
Spontaneous recovery in 1 - 4 weeks!
Energy restricted diet
Moderated exercise
Flooring with good traction
NOT SX!
What is the prognosis for carpal laxity syndrome?
EXCELLENT!
What are the components of the common calcanean tendon?
Gastrocnemius
Gracilis
Semitendinosus
Biceps femoris
Superficial digital flexor
GGBSS=CCtendon
What is the difference between complete and partial rupture
of the common calcanean tendon?
Complete = traumatic, complete plantigrade stance
Partial = chronic, flexion of digits
(because superficial digital flexor usually preserved!)
Describe the specialized suture pattern required for
common calcanean tendon repair
3-loop pulley with monofilament NONabsorbable suture
(tendons are slow to heal, so need non-absorbable)
What is the most important part for post-op care
of a common calcanean tendon repair?
What is the prognosis?
IMMOBILIZATION using coaptation!
ESF, Splint, or giant lag screw
Prognosis generally GOOD! (75% return to function)
What breed is susceptible to OCD of the hock (ankle)?
Rottweilers
T/F:
OCD of the hock is frequently bilateral
TRUE
Where does hock OCD most commonly occur?
MEDIAL side on the ridge of the talus (articulation of tibia)
How does hock OCD common location differ in Rottweilers as compared
to other cases of hock OCD?
If lateral location, predominantly will be a Rottweiler (but medial is still most common in rotties)
What is the significance of the hock flexion test?
Pain at the limits of hock flexion indicates DJD
(not necessarily OCD, but there is a problem)
What is interesting about the lameness that occurs with
OCD of the hock/talus?
It worsens after REST!
What are findings on PE that are indicative of hock OCD?
Lameness that worsens after rest
Hock-extended stance
Joint effusion/fibrosis
Pain/crepitus on manipulation
Pain at limits of hock flexion on flexion test
How is OCD of the hock diagnosed?
Radiographs show articular flattening and lucency
What types of radiographic views are necessary for
diagnosis of hock OCD?
Standard lateral and craniocaudal views (for most)
Flexed lateral (to expose proximal talus)
Flexed craniocaudal (to see cranial trochlear ridges)
What is the most common location of hock OCD?
talar ridge (medial or lateral)
What are the tx option for hock OCD?
Medical tx: Only older dogs with established osteoarthritis
Surgical tx: Fragment excision/debridement (arthroscopy better)
or
Tibiotarsal (tarsocrural) arthrodesis
What is the prognosis for hock OCD?
Guarded to poor :(
Because sx does not prevent development of osteoarthritis or eliminate lameness, it just improves function somewhat
What are the indications for tarsocrural pantarsal arthrodesis?
Severe injury to the tibiotarsal (tarsocrural) joint
(comminuted articular fractures, persistent luxation)
Failed common calcanean tendon repair
Osteoarthritis unresponsive to medical tx
Describe the process of tarsocrural pantarsal arthrodesis
Fuse tibiotarsal (tarsocrural) joint at standing angle (peg leg stance)
Remove articular cartilage
Pack with bone graft
Rigid fixation (Dorsal plate or Type 2 ESF)
What is the long-term outcome for tarsocrural pantarsal arthrodesis?
Loss of hock ROM (mechanical lameness)
but acceptable function
Pet: GOOD
Working dog: Guarded to poor
