Large Animal Carpus and Proximal Limb

Question 1

describe 5 general signs of carpal pathology on exam

Answer 1

1. reduced ROM
2. pain during PROM
3. effusion present on palpation
4. positive flexion exam
5. localized with diagnostic anesthesia

Question 2

describe signs of osteoarthritis within the carpus

Answer 2

1. begins as inflam of joint capsule (synovitis/capsulitis)
2. leads to periarticular osteophyte formation
3. when marked, leads to medial collapse of joint
4. risk of fracture of large osteophytes

treatment: same as for OA in other joints
1. joint injection: steroid or biologic
2. systemic meds: NSAIDs
3. local pain management

prognosis: depends on severity and intended use

Question 3

describe carpal chip fractures

Answer 3

1. most common in racehorses, secondary to hyperextension of carpus due to palmar translation/sliding of proximal carpal row
2. cause acute lameness
3. most commonly at RADIAL CARPAL BONE (EXAM!!!)
4. clinical signs same for OA, but may also have crepitus (crunchiness, don’t walk horse if feel, do rads first)

Question 4

describe carpal slab fractures

Answer 4

1. commonly in racehorses
2. commonly affect:
   -third carpal bone
   -radial carpal bone
   -intermediate carpal bone
3. clinical signs same as OA:
   -may have crepitus; feel grinding or bubble wrap
   -likely VERY reactive to flexion; very painful
   -radiograph BEFORE blocking

Question 5

how do carpal slab fractures occur?

Answer 5

1. cyclic repetitive loading (run fast in a circle in one direction)
2. wolff’s law:
   -increased load = more bone laid down
3. more bone laid down = sclerosis, bone becomes less elastic and has compromised blood flow
4. less elasticity and blood flow = microfractures/stress risers that make animal more predisposed to gross fracture (like a baby tree in the wind versus an old brittle tree in a hurricane)

Question 6

describe common fractures that can occur in the carpus; give treatment and prognosis

Answer 6

1. carpal chip fractures
2. carpal slab fractures

treatment:
chip: take it out!
big fragment: stabilize fracture

if you do nothing = osteoarthritis

prognosis for athletic use:
1. good for small chips, and non-displaced slab fractures if caught early
2. dependent on degree of cartilage damage

Question 7

describe catastrophic fractures

Answer 7

1. traumatic in origin
2. acute treatment is stabilization: lateral splint or palmar splint
3. long-term stabilization
   -carpal arthrodesis: fuse joint = take pain away
   -performed for preservation of life, not return to activity

Question 8

describe carpal hygromas

Answer 8

1. isolated dorsal, fluctuant swelling over the carpus
2. can have a synovial fistula = communication between adjacent synovial structures, may appear as two separate areas of swelling
3. traumatic in origin
4. horses may not be lame if no other pathology present
5. diagnosis:
   -ultrasound: look at fluid pockets for communication
   -contrast radiographs: see communication
   -arthroscopy: intense for a hygroma
6. treatment:
   -anti-inflam/bandaging early
   -surgical resection
   -or do nothing, often cosmetic!
7. prognosis for athletic use: excellent!!

Question 9

describe carpal extensor tenopsynovitis

Answer 9

inflammation in tendon sheath

1. acute or chronic fluctuant swelling of dorsal carpus, often as distal aspect of carpus/proximal metacarpus
2. traumatic in origin, horse usually sound
3. diagnosis:
   -ultrasound
   -synoviocentesis if history of wound
4. treatment:
   -local anti-inflammatories
   -surgery if septic
   -or do nothing! also often cosmetic
5. prognosis for athletic use:
   excellent! cosmetic

Question 10

describe radial distal physis exostosis

Answer 10

1. osteochondroma formation: separation of a portion of border of physis/growth plate due to a separate center of endochondral ossification, so part that is usually cartilage becomes more bone
2. usually located caudomedially
3. we care because bone sticking into carpal canal can impinge on carpal sheath and DDFT and cause lameness
4. diganosis:
   -localize with diagnostic anesthesia
   -rads
   -US carpal canal
5. treatment:
   -tenoscopic removal of exostosis (shave it off)
   -treatment for DDFT injury if present
6. prognosis: dependent on DDFT damage

Question 11

describe ulnar/olecranon fractures

Answer 11

1. traumatic in origin, result in acute, marked lameness
2. may have dropped elbow appearance due to lack of triceps function with displaced fractures
3. swelling/pain on palpation of area
4. diagnosis: rads and NS (for tiny hairline fractures)
5. treatment: surgical repair or just strict stall rest for non-displaced non-articular fractures
6. prognosis for athletic use:
   -closed fracture: good if non articular
   -open fracture: guarded, high risk of infection

Question 12

describe radial fractures

Answer 12

1. traumatic in origin resulting in acute marked lameness (non weight bearing if complete/displaced fracture)
2. swelling of antebrachium; wound may present medially
3. diagnosis: rads and NS
4. treatment:
   -conservative: stall rest if incomplete/non-displaced
   -if complete/displaced: recommend euthanasia due to poor prognosis
5. prognosis:
   -incomplete/nondisplaced: good
   -complete/displaced: grave

Question 13

describe osteoarthritis of the elbow/shoulder

Answer 13

1. rare in horses! more common in pot belly pigs
2. typically secondary to degenerative/traumatic changes
3. highly variable degree of lameness
4. often no obvious clinical signs on palpation; effusion difficult to palpate in these joints
5. may have resentment to flexion of joint
6. diagnosis:
   -diagnostic analgesia
   -radiographs
7. treatment:
   -similar to OA in other locations, elbow OA is often more difficult to treat
8. prognosis for athletic use: dependent on degree of OA/inciting cause

Question 14

describe olecranon bursitis

Answer 14

1. capped elbow/elbow hygroma, shoe boil; due to repeated trauma over olecranon
2. bursa not normally present but forms from the trauma
3. often seen in horses shod in the forelimbs that lay in sternal frequently (see pic in slide for reference)
4. fluctuant swelling that does not cause lameness
5. cosmetic, difficult to resolve once present
6. place bell boot upside down to prevent!

Question 15

describe humeral/scapular fractures

Answer 15

1. occur in racehorses in training; stress fractures that can become complete or
2. can occur in other horses due to trauma
3. cause acute, severe lameness
4. if fracture is displaced/complete will have swelling/pain on palpation
5. scapular fractures can occur along body, spine, or supraglenoid tubercle
6. treatment:
   -conservative if stress fracture/nondisplaced
   -if complete/displaced: recommend euthansia
7. prognosis for athletic use:
   -good if incomplete/nondisplaced
   -grace if complete/displaced