Page 347 - Cote clinical veterinary advisor dogs and cats 4th

146 Carpal Trauma/Breakdown

• Shearing/degloving wounds Differential Diagnosis (minimal instability) ligament sprains are
externally splinted 4-8 weeks.
• Coaptation-related injuries • Immune-mediated polyarthropathy • Luxated joints, intraarticular fractures, and
VetBooks.ir HISTORY, CHIEF COMPLAINT • Carpal laxity syndrome grade III sprains are initially supported in
• Infectious (Lyme borreliosis, rickettsial
diseases, septic arthritis)
• Forelimb trauma, especially falling/jumping
a modified Robert Jones bandage or splint
injuries
○ Hyperextension injuries are managed with
• Lameness • Flexor tendon lacerations (p. 1161) until further treatment.
• Slowing/drifting wide on racetrack turns Initial Database partial or pancarpal arthrodesis.
• Orthogonal radiographs of the distal limb ○ Collateral ligament injuries are usually
PHYSICAL EXAM FINDINGS • CBC and serum biochemistry panel replaced with prosthetic sutures.
• Lameness (see Video). • Electrocardiography and thoracic radiography ○ Radial carpal bone luxation is treated with
• Carpal swelling (if massive trauma has occurred) reduction and screw fixation; pancarpal
• Pain/crepitation during palpation arthrodesis may be indicated for com-
• Open wounds Advanced or Confirmatory Testing minuted or chronic fractures.
• Instability characterized by palmigrade or • Oblique radiographic views and/or CT to ○ Accessory carpal bone fractures are treated
hyperextended carpal stance outline nondisplaced fractures with lag-screw fixation or external coapta-
• Mediolateral instability • Stress radiography (mediolateral view with tion for comminuted fractures.
carpus forced into hyperextension, and • Small radial and accessory carpal bone
Etiology and Pathophysiology dorsopalmar views with medial/lateral stress fractures have good outcomes with surgical
• In pets, hyperextension or ligament injuries applied) for localizing level of instability excision.
are more common than fractures. • Shearing injuries, after initial wound man-
• Erosive polyarthropathies can lead to carpal TREATMENT agement, are covered and supported until
ligament injury or hyperextension. definitive treatment.
• Incomplete fusion of centers of ossification Treatment Overview ○ Gentle wound lavage using saline, lactated
of the radial carpal bone may predispose this The goal of therapy is to re-establish normal Ringer’s or dilute chlorhexidine solutions.
bone to fractures. anatomy and restore pain-free function: ○ Wounds are debrided and bandaged until
• In racing animals, fractures usually involve • Ligamentous injuries: re-establishment definitive stabilization is done; honey or
the accessory carpal bone. Track animals of carpal support with ligament repair, sugar application may be useful with
racing counterclockwise are predisposed to arthrodesis, or external coaptation in some highly contaminated wounds.
right-sided injuries (80%). cases. ○ Wounds with healthy granulation tissue
• Fractures: anatomic reduction and stabilization and early epithelialization can be sutured
DIAGNOSIS • Shearing injuries: wound management, and or covered with a nonadherent dressing
surgical stabilization if needed and allowed to heal by second intention.
Diagnostic Overview
Diagnosis of carpal pathology is mainly based Acute General Treatment Chronic Treatment
on physical and radiographic examinations. • Minimally displaced nonarticular fractures, • Some surgical repairs require 4-12 weeks of
grade I (no instability), and most grade II external coaptation and exercise restriction.
• Chronic fractures and instabilities with
resultant osteoarthritis are treated with carpal
arthrodesis.
Possible Complications
• Reduction/implant failure
• Delayed/failed arthrodesis
• Wound infection
• Coaptation-related morbidity
• Degenerative joint disease
Recommended Monitoring
• Lameness evaluation 1-3 months after injury
and treatment
• Serial radiographic studies to evaluate fracture
healing or progression of arthrodesis

PROGNOSIS & OUTCOME
• Good to excellent for noncompeting dogs
• Varies for athletic dogs needing to return to
preinjury competition levels
• Severe shearing injuries with neurovas-
cular compromise may necessitate limb
amputation.
PEARLS & CONSIDERATIONS
CARPAL TRAUMA/BREAKDOWN Oblique view,
CARPAL HYPEREXTENSION Mature malamute three-dimensional CT reconstruction demonstrates a Comments
with left palmar carpal hyperextension. (Courtesy Dr. distal radial articular fracture (arrows) that could not • Complete palmar carpal breakdown/
Joseph Harari) be seen on orthogonal radiographs. hyperextension requires arthrodesis.

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