The carpus, metacarpus and digits

Question 1

What are two major anatomic differences between the canine and feline manus?

Answer 1

1. The ability to retract the claws due to the anatomy of the dorsal elastic ligaments and structural differences in the middle and distal phalanx.
2. Only a straight component in the feline medial collateral ligament of the carpus (compared to straight and oblique for the dog)

Question 2

What are the three common configurations of intermedioradial carpal bone fractures?

Answer 2

Dorsal slab, sagittal mid body, T-fractures. These are proposed secondary to failure of fusion of the 3 centers of ossification.

Question 3

What is the most common configuration of interomedioradial carpal bone fracture in the Greyhound?

Answer 3

Oblique midbody fractures of the right side

Question 4

What are the options for repair of a interomedioradial carpal bone fracture?

Answer 4

Lag screw, headless self compressing cannulated screw, K-wires

Question 5

What is the most common presentation of right accessory carpal bone fractures?

Answer 5

Type 1 fracture of the right accessory carpal bone in racing greyhounds

Question 6

What are the five classifications of accessory carpal bone fractures?

Answer 6

Question 7

What are the surgical options for accessory carpal bone fractures?

Answer 7

Lag screw fixation or fragment removal

Question 8

What are the traditional guidelines for metacarpal fracture repair as modified from the human literature?

Answer 8

(1) if more than two metacarpal or metatarsal fractures are present in the same manus
(2) if the fractures involve both of the primary weight-bearing bones (metacarpals or metatarsals III and IV)
(3) if the fractures are articular fractures
(4) if the fracture fragment segments are displaced by >50%
(5) if the fracture involves the base of metacarpal/metatarsal II or V
(6) if the dog is a large-breed or athletic working or show dog

Question 9

What are the 3 types of metacarpal fractures seen most commonly in racing Greyhound?

Answer 9

Type 1: endosteal and cortical bone thickening.
Type 2: minimally displaced hairline fractures
Type 3: complete fractures with fragment displacement

Most commonly seen in metacarpal V of the left thoracic limb, or metacarpal II of the right thoracic limb

Question 10

What are surgical repair options for metacarpal fractures?

Answer 10

Intramedullary K-wires, dowel pinning, small bone plates, external fixation.

Question 11

What are the breeds most affected by sesamoid disease?

Answer 11

Rottweilers and greyhounds. Sesamoids II and V most VII most commonly affected.

Question 12

What is the recommended treatment for sesamoid disease?

Answer 12

Conservative management (no different to surgical outcomes). Surgery consists of sesamoid removal and may destabilize the joint

Question 13

Damage to which structures results in carpal hyperextension injury?

Answer 13

Flexor retinaculum and palmar fibrocartilage

Question 14

What is the distribution of carpal luxation injuries in the dog?

Answer 14

Antebrachiocarpal: 31%
Middle carpal: 22%
Carpometacarpal: 47%

Question 15

Which is the most common joint injured in the cat with carpal hyperextension injury?

Answer 15

Antebrachiocarpal joint: 50% of the time

Question 16

Which side of the carpus is most commonly affected with shearing injuries?

Answer 16

Medial aspect (69%)

Question 17

Which tendon is most commonly affected in flexor tendon laceration injuries?

Answer 17

The deep digital flexor tendon. Results in dorsal deviation of the distal phalanx

Question 18

What are the grades of carpal collateral ligament injury?

Answer 18

Grade 1 or 2: sprains
Grade 3: complete rupture

Question 19

What are the indications for pancarpal v partial tarsal arthrodesis?

Answer 19

Pancarpal arthrodesis is recommended if the antebrachiocarpal joint is involved, or if there is displacement of the ulnar carpal or accessory carpal bones.

Question 20

What is the angle used in pancarpal arthrodesis?

Answer 20

10-12 degrees of extension

Question 21

What is the tension surface of the carpal joint?

Answer 21

The palmar surface. Not commonly used due to significant soft tissue dissection required for implant placement

Question 22

What are general surgical recommendations regarding carpal arthrodesis to limit complications?

Answer 22

Screw diameter should be no more than 40% of the metacarpal bone diameter, plate should span 50% of the length of metacarpal 3, proper alignment should be ensured, and the articular cartilage should be adequately removed

Question 23

Where is the major stress location in a pancarpal arthrodesis?

Answer 23

Distal to the last metacarpal screw

Question 24

How much does the antebrachioradial joint contribute to overall carpal movement?

Answer 24

85%

Question 25

What surgery is typically indicated in complete luxation of any carpal joint/bone?

Answer 25

Pancarpal arthrodesis

Question 26

What are the most common metacarpophalangeal joints to be affected by osteoarthritis?

Answer 26

Metacarpals IV and V

Question 27

Is carpal laxity syndrome more common in female or male dogs?

Answer 27

2:1 male predelication

Question 28

What is the most common type of digital mass in dogs?

Answer 28

Squamous cell carcinoma, followed by melanoma, soft tissue sarcoma and mast cell tumour. Subungual SCC had a worse prognosis.

Question 29

What is the most common type of digital mass in cats?

Answer 29

SCC

Question 30

Where are the majority of paw pad corns found in Greyhounds?

Answer 30

Digits 3 and 4 of the thoracic limbs (90%)

Question 31

What is the recurrence rate of paw pad corns following surgical excision in Greyhounds?

Answer 31

50%