Carpus-Biedrzycki Flashcards
Diseases of the carpus
- Synovitis (esp racehorses)
- Intra-articular carpal bone fractures
- Accessory carpal bone fractures
- Subchondral bone cyst like lesions (SBCs)
- Luxation
- Carpal hygroma
Joints of the carpus
- Radiocarpal joint (RCJ)
- Middle carpal joint (MCJ)
- Carpometacarpal joint
Proximal row of carpal bones
- radial carpal bone
- ulnar carpal bone
- intermediate carpal bone
- accessory carpal bone
Distal row of carpal bones
- 1st 2nd
- third
- fourth
- Sometimes fifth
Things that communicate
- RCJ and MCJ communicate ~ 5% cases
- RCJ and carpal sheath communicate ~ 5% cases
- MCJ and CMC communicate 100% of the time
Common carpal injuries in foals
- Cuboidal bone hypoplasia and collapse
- Sepsis
- Osteomyelitis
Common yearling injuries
osteochondral chip fragment
Common adult injuries
Ush racehorses
- osteochondral chip fragmentation
- SBCs
- Palmar intercarpal desmitis
Osteochondral chip frag etiology
- Weightbearing is dorso-medial (RCB, C2, C3 at greatest risk)
- Submaximal stress remodeling
- Trauma during exercise-subchondral sclerosis
- microfractures or gross fractures - Supra maximal trauma
- fracture
Predispositions to carpal fractures in racehorses
- Conformation (back at the knee)
- Muscle fatigue in untrained horses/end of exercise
- Racing ground type
Due to racing direction in states
lateral aspect of left carpus frequently affected
medial aspect of right carpus frequently affected
Slab fractures are
bi-articular
Radiographs
Standard 4 views
Flexed Lateromedial
Skyline of proximal and distal rows
CS
- joint effusion
- pain on flexion
- IA anesthesia in chip fractures ONLY
OC frag TX
Prompt surgical removal to maximize prognosis
Prognosis
- Depends on degree cartilage loss
- Age of fracture
- Presence of DJD
70-80% return to racing
Slab fracture tx
Requires internal fixation
65-75% return to previous performance level
Standardbreds slightly better prognosis than TBs
Pancarpal arthrodesis is salvage and last resort
Accessory carpal bone fractures
- Usually vertical fissure along lateral groove of ulnaris lateralis m
- treatment is conservative or surgical, end result fibrous union
- carpal canal syndrome is possible complication
Subchondral bone cysts
- usually young horses, can be any bone (distal radius and UCB most common)
- tx can be conservative or surgical and prognosis depends on accessibility of cyst
- radial cyst prognosis good
Carpal luxations
- rare, assoc with collateral ligament damage +/- fx
- acute lameness
- tx closed reduction and full imb cast application
- prognosis good if no carpal fx or cartilage damage
Carpal Hygroma
Membranous, synovial fluid filled swelling over dorsal surface carpus
-ush assoc with trauma
Carpal hygromas MAY communicate with
- RCJ
- MCJ
- Extensor carpi radialis tendon sheath
Carpal hygromas CS
Non-painful, not lame
Carpal hygromas DX
- PE
- U/S
- Contrast radiography for communications
Carpal hygromas TX
- needle drainage
- corticosteroid injection (+ atropine sulfate)
- Systemic NSAIDS
- Pressure bandage
- Stall rest
Chronic cases may need debridement or penrose drain
Carpal hygroma prognosis
Acute-good
Chronic-poor (accumulation excessive fibrous scar tissue can limit ROM)
Osteochondroma
- Benign tumor of bone
- often on caudodistal aspect of radius
- don’t cause lameness unless in bad spot
- removed surgically and dont recur
