17. ruminant musculoskeletal conditions

identifying fractures

• asymmetry

  • limb is misaligned / unstable

• abnormal mobility

  • non-weight bearing lameness

  • acute, severe lameness

• audible crepitus

  • loud crack heard

  • crepitus felt or heard

stabilizing patient

• triage

  • assess overall patient

  • assess injury site

• sedation

  • ease of examination, treatment, and transportation

• fluid therapy

  • rarely severe hemorrhage

• other meds

  • pain management

  • infection control

when might medical treatment alone not be an option?

• compound / open fracture

  • contamination by environment for hrs

• neurological status

  • check deep pain

  • radial / sciatic nerve paralysis

• patient temperament — fractious animals

what fracture locations are better for repair? which are not?

• below carpus / tarsus (distal) → green light

• joint breaks (articular) → yellow light; osteoarthritis

• above carpus / tarsus (proximal)

  • radius / ulna & tibia → red light; referral

  • femur / humerus → red light

    • adults — salvage

    • calves — stall rest

when is field repair appropriate?

age/weight, location, fracture type, economics

• age/weight: calves; <150 kg

• location: metacarpus / metatarsus

• fracture type: single, closed, transverse

• economics: low cost; splint / cast

when is referral / surgery appropriate?

age/weight, location, fracture type, economics

• age/weight: adults; 150 to >400 kg

• location: above carpus / tarsus

• fracture type: comminuted, open, articular

• economics: high value; internal fixation

robert jones bandage

• thick layers of cotton

• compressed with gauze and vet wrap

• leave toes out

• 3x diameter of limb

• sound like “ripe melon”

modified robert jones bandage is less bulk alternative (1-2x diameter of limb)

what is the rule of two in regards to splint application?

splint should extend to the joint above and joint below fracture

types of splints

• modified thomas schroeder splint cast

  • used in radial, tibial, humeral, and femoral fractures

  • not frequently used in small ruminants

• walker splint

  • used in upper rear limb fractures

• modified spica splint

  • proximal forelimb fractures

splinting technique for digit / fetlock fractures

dorsal splint

• target stabilization: align bone column

splinting technique for MC / MT fractures

lateral and dorsal

• target stabilization: neutralize bending forces

splinting technique for carpus / tarsus fractures

lateral to scapula / hip

• target stabilization: prevent limb abduction

splinting technique for proximal limb fractures

thomas splint

• target stabilization: neutralize weight bearing

splint aftercare

• stall confinement

• daily evaluation of splint & animal

  • reset of splint and bandages every couple of days

  • check animal not lying down on splint

    • rumen tympany

    • death

• assist animal 3-5 days until they know how to rise

what types of fractures are appropriate for casting?

• simple transverse or short oblique diaphyseal fractures

• metaphyseal fractures

  • salter harris type 1 & 2

• minimally displaced / incomplete fractures

characteristics of plaster of paris

ease of molding, strength to weight, setting time, durability, radiographic clarity, and cost

• easy of molding: excellent; conforms to limb

• strength to weight: heavy; many layers necessary for strength

• setting time: slow; 10-15 mins; full strength 24h

• durability: poor; mush when wet

• radiographic clarity: opaque

• cost: very low

characteristics of fiberglass casting

ease of molding, strength to weight, setting time, durability, radiographic clarity, and cost

• easy of molding: moderate; less forgiving

• strength to weight: superior; lightweight and strong

• setting time: fast; 3-5 min

• durability: excellent; water-resistant

• radiographic clarity: radiolucent

• cost: higher

cast application

• sedation / general anesthesia needed

• do not end near fracture line or mid-diaphysis

• immobilize joint above and below fracture

• limb in neutral position

• include foot to create walking cast (left out in bandages)

• adequate padding

  • bony prominences

  • between claws

• stockinette or orthopedic felt

• fiberglass tape

  • 50% overlap

  • 6-8 layers in calf; 12-16 in adult

  • include rods/waling bar

• protect bottom with technovit, acrylic resin

  • rubber anti-slip

what is the 1 finger rule in regards to cast application?

cast should snugly fit 1 finger between padding and animal skin

how often should casts be changed?

• young animals: 2-3 weeks

• adult animals: 4-6 weeks (should still be checking on animal every 2-3 wks)

cast variations

• bandage cast technique

  • inner layer: modified robert jones bandage

  • outer layer: fiberglass material

• hybrid cast technique

  • cast padding

  • inner layer: 1-2 rolls of plaster of paris

  • outer layer: fiberglass material

cast aftercare

• clean, dry environment

• “sniff test” — check for foul odor

• mobility & weight bearing

  • sudden lameness

  • knuckling over/dragging

• comfort & behavior

  • incessant licking/chewing

  • systemic signs

  • swelling at top of cast

• physical integrity

  • cracks/soft spots

  • discharge

  • bottom of cast

cast complications in injured limb

• loss of range of motion in joints

• pressure sores

• mal-alignment, non-union

• peroneus tertius rupture

• reduction in cartilage health

cast complications in contralateral limb

• tendon / ligament laxity

• angular limb deformity

how can synovial structures become infected?

• primary — direct trauma

• secondary — adjacent infection

• tertiary — systemic hematogenous infection

juvenile vs. adult synovial infection

juveniles

• tertiary hematogenous

• poly-articular

adults

• direct trauma and adjacent

• mono-articular

clinical signs of synovial infection

• severe lameness

• soft tissue swelling around synovial structure

• effusion of synovial structure

• wound / external trauma

• ± fever

diagnosing synovial infection

• radiography

  • 10-14d for osseous changes

  • changes are osteomyelitis, periosteal proliferation (?)

  • subchondral bone lysis

• ultrasound examination

• centesis

  • macroscopic

  • cytology

  • culture / sensitivity

synovial infection treatment

• joint lavage / debridement

  • needle lavage (if caught early ↓ fibrin)

  • arthrotomy — indicated to manually remove extensive fibrin clots

  • athroscopy

• medication

  • antimicrobials: systemic & local

  • NSAIDs

synovial infection prognosis

depends on duration and severity

• joints: good to fair (70-80%)

• sheaths and bursas: guarded to poor

etiology of coxofemoral luxation

• adults: trauma

• juveniles: forced extraction

coxofemoral luxation clinical signs

• varies with location of femoral head

• toe touching lame

• dropped hip appearance

diagnosing coxofemoral luxation

• palpation — externally & internally

• clicking sounds

• radiographs

  • craniodorsal most common luxation

• ultrasound

  • femoral head more superficial

coxofemoral luxation treatments

• closed reduction

  • traction applied under general anesthesia

  • 40-50% recurrence rate

• open reduction

  • traction + direct surgical joint access under general anesthesia

  • joint capsule reinforcement

  • attempt for reduction

  • limitations due to animal size

coxofemoral luxation prognosis

• moderate to good if < 12h injury

• poor if >12h injury, fracture, and animal non-ambulatory