Carpal Luxation and Medial Collateral Ligament Injury Flashcards
What are the 3 levels Hyperextension and subsequent subluxation or luxation can occur at?
The antebrachiocarpal level proximally.
The intercarpal level in the middle.
And the carpometacarpal level distally.
What are the 2 most common injuries to the canine carpus leading to loss of palmar support and carpal hyperextension?
Damage to the flexor retinaculum
The palmar fibrocartilage
What is the typica history leading to carpal hyper extension/subluxation?
There is typically a history of trauma, like jumping or falling from a height, but non-traumatic aetiology, e.g. in relation with immune-mediated arthropathies, is possible.
Order these from least - most common level for carpal luxation?
antebrachiocarpal
Carpometacarpal
Middle carpal
antebrachiocarpal (10-31%), carpometacarpal (40-47%) level.
middle carpal (22-50%)
In one study, how many cats with hyperextension injury had the antebrachial joint involved?
50%
What degree of lameness is often seen with carpal hyperextension/luxation?
Following an acute injury, the animals are often non-weight bearing initially, but then symptoms can become more subtle with only mild lameness
What is seen on CE with carpal luxation/hyperextension? (4)
Swelling and tenderness of the carpus,
Discomfort on palpation
Possibly crepitus
Altered ROM.
What imaging is needed to assess carpal luxation/hyperextension/what is being ruled out?
Orthogonal radiographs with standard dorsopalmar and mediolateral views of both carpi are indicated to assess for bony injuries or pre-existing degenerative joint disease.
Are stress radiographs important for assessing carpal hyperextension/subluxation?
Yes, stress radiographs are necessary to accurately assess carpal integrity and to identify the exact level of joint instability.
What degree of hyperextension during stress radiography indicates a dx?
15-20
How successful is conservative management of hyperextension?
Rare to be
What are generally considered as the best treatment option for carpal hyperextension? (2)
Pancarpal arthrodesis
Partial carpal arthrodesis
Medial collateral ligament injury of the feline carpus:
Carpal Medial ligament deficiency results in what instability? (2)
Valgus
Dorsopalmar
Medial collateral ligament injury of the feline carpus:
Which direction of instability is more obvious on exam with a medial ligament deficiency?
Dorsopalmar
Medial collateral ligament injury of the feline carpus:
What +ve sign is present with dorsopalmer instability of the carpus?
Radiocarpal drawer
What x rays are taken with Medial collateral ligament injury of the feline carpus? (2) What is ruled out?
Mediolateral and dorsopalmar radiographs are taken to rule out fractures and to assess for pre-existing degenerative joint disease.
Medial opening of the radiocarpal joint in valgus stress radiographs more pronounced in dogs or cats?
Dogs
What is the treatment of choice for feline medial collateral ligament rupture resulting in either subluxation or luxation?
Primary surgical reconstruction including placement of a ligament prosthesis
Following feline medial collateral ligament rupture, how can temporary immobilisation be performed?
a splint, cast or transarticular ESF is required for 3 - 4 weeks after primary repair
How long does it take for recovery back to near full leg function with feline medial collateral ligament rupture? What is likely to develop?
Several months
OA expected to develop
Area medial or lateral collateral ligament injuries more common in dogs?
Medial but still rare
What are the 2 parts of the medial collateral ligament?
Straight + oblique
Straight part of the medial collateral ligament:
A) Origin?
B) Insertion?
C) Which aspect is it closely attached to the sheath of the abductor pollicus longus tendon?
A) prominent unnamed tubercle on the medial aspect of the distal radius
B) O the most medial part of the palmar process of the radial carpal bone.
C) Dorsal
Oblique part of the medial collateral ligament:
A) Originates?
B) Runs obliquely under the tendon sheath of… where?
A) On the styloid process of the radius
B) runs obliquely under the tendon sheath of the abductor pollicus longus muscle to the palmaromedial surface of the radial carpal bone.
When is the straight part of the medial collateral ligament taught?
Extension
When is the oblique part of the medial collateral ligament taught?
Flexion
What is the degree of lameness with medial collateral ligament injury?
Usually weight-bearing lame
What is found on CE with medial collateral ligament injuries? (3)
- Swelling on medial aspect of joint
- Painful ROM
- Valgus instability
What imaging should be performed to investigate medial collateral ligament injury?
Plain + stressed x rays
What is the treatment recommendation for medial collateral ligament damage?
Ligament prosthesis
What needs to be provided post op with medial collateral ligament damage?
Postoperative support is required for four to six weeks, using either external coaptation with a splinted modified Robert Jones bandage or cast, or a transarticular ESF.
How can gradual return to function after medial collateral ligament injury be aided?
Physiotherapy
What does long term prognosis of medial collateral ligament injury depend on?
Developmental/clinical consequence DJD
How common are complete luxations of carpal bones/joints?
RARE
What is the likely needed treatment of complete carpal bone/joint luxation?
Pancarpal arthrodesis
Individual bones of the carpus may luxate partially or completely.
Which carpal bones are more commonly involved? (3) Which direction
The bones most commonly involved are the radial carpal bone or carpal bones I and II. Usually they displace dorsally.
How can individual bone luxations of the carpus be managed non-surgically? What is the main issue?
Closed reduction may be possible followed by external immobilisation for 2 to 4 weeks.
Most closed reductions do not have good soft tissue healing and subluxation typically recurs.
What is the main way of achieving satisfactory outcomes of individual carpal bone luxations?
carpal arthrodesis
When do Luxation and proximal displacement of the accessory carpal bone occur?
When the two ligaments attaching the bone distally to the base of metacarpals IV and V tear or avulse
What is luxation of the accessory carpal bone is found in association with palmar luxation or subluxation of which joint?
Antebrachiocarpal joint
Tears of the palmar carpal fibrocartilage and palmar transverse carpal ligament often occur..?
Simultaneously
Luxation of the accessory carpal bone:
A) Animal posture?
B) What is palp on accessory carpal bone?
C) What is demonstrated in the flexor carpi ulnaris muscle?
A) Plantigrade
B) No prominence
C) Laxity
Is the following sentence true or false?
External immobilisation of the limb, to relocate the bone should be attempted soon after accessory carpal bone luxation is diagnosed.
False - External immobilisation of the limb does not relocate the bone and therefore does not result in success.
What position is the carpus for open accessory carpal bone relocation?
Flexed
What a are the possible methods of surgical repair of the accessory carpal bone?
Suture of the palmar carpal fibrocartilage
Wiring the caudal tip of the accessory carpal bone to the base of metacarpal V,
Both.
If surgery of accessory carpal bone luxation fails. What is next step?
arthrodesis of one or all levels of the carpus is necessary to stabilise the joint.
