Orthopedics

Created by phlancelot 

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system for naming luxations

proximal end of distal bone relative to distal end of proximal bone

DDx for lameness

-cranial cruciate ligament rupture
-elbow dysplasia
-hip dysplasia
-carpal hyperextension injury
-foreign body in pad
-torn/overgrown nail
-interdigital dermatitis/abscessation
-fractures
-dislocations/luxations
-bone tumours
-arthritis
-myopathy
-neuropathy
-cat-bite abscess
-Lyme diz.
-other rare infections

approach to a lameness case

-detailed history (onset, duration, progression, previous diz or trt, general health)
-physical exam (general vs ortho vs neuro)
-aides to diagnosis (rads, u/s, MRI/CT, joint tap, arthoscopy, blood tests)

the walk

4, 3, or 2 legs support the animal at one time

the trot

2 contra-lateral legs support the body at one time

the pace

2 ipsi-lateral legs support the body at one time

components of a stride

-stance phase
-swing phase

the gallop

not often used to assess lameness

observations at trot in a lame animal

-swing/stance shortened (to minimize weight bearing/painful time)
-head down on sound (forelimb)
-butt sinks on sound (hindlimb)

two most common questions asked when radiographs are referred for a second opinion

1) is this a tumour?
2) what is wrong with this elbow?

descriptive terms for new bone

-proliferation
-amorphous (tumour)
-florid
-onion/lamellated (recurrent)
-palisading
-extensive (osteomyelitis)

descriptive terms for destruction of bone

-lysis
-motheaten
-permeative

factors affecting skeletal radiograph judgement

-species
-age
-breed
-history
-clinical signs

monostotic

one bone affected

polyostotic

multiple bones affected

polyarthropathy

multiple joints affected

sequestrum

dead bone (radio-opacity) surrounded by a radio-lucent halo on radiograph

notable radiographic soft tissue changes

-atrophy
-mineralisation
-intra-articular (osteochondroma - aka - joint mice)
-displacement

zone of transition

margin between normal and abnormal bone
-longer: aggressive, tumour, infection, early healing
-shorter: benign, quiescent, settled

bone/soft tissue border radiographic considerations

-ill-defined: aggressive
-defined: benign, quiescent, old

when assessing a joint radiographically, check for...

-poor formation (dysplasia/luxation)
-degerenation (OA, DJD)
-joint space changes (osteophytes)
-subchondral bone (retained cartilage)
-periarticular bone (stabilization attempt)
-joint mice

enthesiophyte

new bone laid down at the site of ligamentous or tendinous insertions

categories of diz. detectable radiographically

-congenital
-developmental
-traumatic
-infective
-neoplastic
-nutritional
-degenerative

anatomical classifications of a fracture

-avulsion
-diaphyseal
-physeal
-articular

Salter-Harris type 1

transverse fracture through physis

Salter-Harris type 2

fracture through physis and metaphysis (epiphysis spared)

Salter-Harris type 3

fracture through physis and epiphysis (metaphysis spared)

Salter-Harris type 4

fracture through physis, metaphysis, epiphysis

Salter-Harris type 5

compression fracture of physis, decreased perceived space between epiphysis and diaphysis

Salter-Harris type 6

peripheral physis injury resulting in boney bridge formation +/- angular deformity

SALTER mnemonic

S = slip, straight across
A = above, away from joint
L = lower, below physis
T = through all regions
E = everything, epiphysis
R = ring

Salter-Harris diagram

green-stick fracture

periosteum is intact - fracture line only on one side of bone

primary bone healing

only when using plates and compression - very slow healing, can take up to a year (but rapid return to activity)

secondary bone healing

external skeletal fixator - heal faster

forces that can act on a fracture

-compression
-tension
-rotation
-bending
-shear

factors to consider in fracture management

-assess patient (trauma?)
-is it pathological?
-patient factors (co-morbidities, age)
-owner factors ($$$, commitment)
-environment factors (stairs, farm dog)
-surgeon factors (experience, equipment)
-fracture analysis (open vs closed)
-forces acting on fracture
-is anatomical reduction possible?

force/implant neutralization table

4 As of an implant re-check appointment

-apposition
-alignment
-activity
-apparatus

most important first aid step in managing an acute equine fracture

effective emergency fracture stabilization (localize to a "limb level")

equine limb fractures with a hopeless prognosis (in the majority of cases)

open comminuted # OR complete # of the humerus, tibia and femur in adult horses over 300kg

ideal equine fracture for treatment

-distal limb
-no wound, minimal soft tissue damage
-simple, incomplete, stable
-non-articular
-just one injury

stabilization of a stable level 1 fracture

-no bandage material proximal to antebrachiocarpal (knee) or tarsocrural (hock) joint
-splint should make contact with foot and proximal meta-carpal/tarsal 3

stabilization of a level 2 fracture forelimb

-splint from elbow to ground caudally and laterally over a modified Robert Jones bandage to the elbow

stabilization of a level 2 fracture hindlimb

-plantar and tarsal splints over modified Robert Jones bandage which includes hock
-plantar splint along tuber calcis

stabilization of a level 3 fracture forelimb

-as for level 2 with splint extending laterally up side of chest

stabilization of a level 3 fracture hindlimb

-as for level 2 but bandage as far proximally as possible and extend lateral splint to lateral thigh

ancillary first aid in an acute equine fracture

-tetanus prophylaxis
-IV broad spectrum antimicrobials if wounded
-analgesics (bute, banamine)

complications of (equine) fracture treatment

-osteomyelitis
-delayed union, non-union, malunion
-implant failure
-"breakdown" of contralateral limb
-tendon/ligament laxity in foals
-"fracture diz." if immobilised for a long time
-osteoarthritis

DDx for acute severe lameness in the horse

-fracture
-subsolar abscess
-severe joint diz.
-septic tenosynovitis or bursitis
-severe tendon or ligament strain
-cellulitis, lymphangitis
-laminitis
-rhabdomyolysis

DDx for lameness in the immature large breed dog

-hip dysplasia
-osteochondrosis dissecans
-patellar luxation
-cranial cruciate ligament diz

hip dysplasia (conservative treatment)

-body weight/condition management
-NSAIDs
-low impact exercise/physio (swimming?)
-nutraceuticals
-alternative therapies: omega 3 FA diets, acupuncture

hip dysplasia (surgical options)

-triple pelvic osteotomy (<1 year old, + Ortolani sign, no radiographic OA)
-juvenile pubic symphysiodesis (12-20 week old, no clinical signs but radiographic abnormalities, induces premature symphysis closure)

hip dysplasia (salvage procedures)

-femoral head and neck ostectomy (if all else fails)
-total hip replacement (if owners not cost-prohibited)

osteochondrosis dissecans

-disorder of endochondral ossification
-cartilage flap = dissecans
-secondary OA develops (commonly stifle/tarsus)
-4-8 month large breed dog with effused, painful joint
-conservative management
-flap removal by arthrotomy/arthroscopy
-osteochondral grafts (new)

commonest orthopedic condition in general practice

osteoarthritis

clinical definition of osteoarthritis

a slowly evolving articular disease characterised by the gradual development of joint pain, stiffness and limitation of movement

general and life-style changes to managing OA

-reducing diet if obese
-exercise program (as much as dog can cope with)
-physiotherapy (especially hydrotherapy)

pharmaceutical management of OA

-NSAIDs
-matrix supplements (nutraceuticals, injectable)
-omega-3 essential fatty acid supplements
-other drugs (tramadol, gabapentin, amantadine, amitriptyline)

DMOADs used in managing equine OA

-triamcinolone acetonide
-polysulphated glycosaminoglycan
-IRAP
-cartrophen
-chondroitin sulphate
-glucosamine

bone spavin

-osteoarthritis of distal hock joints (distal intertarsal most commonly affected)
-result of poor conformation, chronic repetitive trauma

DDx for chronic, low-grade lameness in horse

-osteoarthritis
-foot pain (navicular diz. or poor foot balance)
-chronic desmitis (eg. proximal suspensory ligament)
-subchondral bone cyst
-chronic laminitis

carpal joint disease (equine)

-OA in a high motion joint
-often in racehorses due to underlying subchondral bone change
-chip fractures are common, may require removal

commonest cause of hindlimb lameness in the adult dog

cranial cruciate ligament disease

how to Dx cranial cruciate ligament diz.

-history, signalment
-radiography under sedation
-palpation under sedation (cranial drawer and tibial compression test)

surgical options for cranial cruciate ligament repair

-extracapsular suture (cheaper alternative)
-tibial tuberosity advacement (TTA)
-tibial plateau levelling osteotomy (TPLO)
-tibial wedge ostectomy (TWO)
-triple tibial osteotomy (TTO)

post-op care of cranial cruciate repair Sx

-analgesia (opioid, NSAID)
-rehabilitation
-re-assess @ 6 weeks w/radiographs
-complications (infection, fracture, late meniscal injury)

goal of cranial cruciate ligament repair Sx

stabilize stifle by altering mechanics - eliminate craniocaudal shear

DDx for hindlimb lameness in an adult dog

-cranial cruciate ligament disease
-hip osteoarthritis
-trauma (fracture/luxation)
-patellar luxation
-lumbosacral disease
-intervertebral disk disease
-neoplasia
-immune mediated arthritis
-muscle and tendon disorders
-footpad disorders

conservative management plan for medial coronoid disease

-improve body weight/condition
-NSAIDs
-low impact exercise/physio
-neutraceuticals/alternative therapies

components of elbow dysplasia

-medial coronoid disease (common)
-ununited anconeal process
-incomplete ossification of the humeral condyle

treatment options for ununited anconeal process

-conservative management
-excision of fragment (first opinion?)
-ulnar osteotomy and lag screw fixation (referral)

IOHC

-young and spaniels
-painful on elbow extension
-well positioned radigraphs or CT for Dx
-high infection risk with transcondylar screw Sx

most common cause of forelimb lameness in the horse

foot pain

DDx for acute severe lameness in the horse

-subsolar abscess
-acute laminitis
-acute solar bruising
-penetrating injury
-pedal bone fracture

DDx for chronic low grade lameness in the horse

-navicular disease
-foot imbalance
-osteoarthritis
-hoof wall crack
-ossified collateral cartilages
-keratoma
-chronic laminitis

navicular disease

a chronic, degenerative and progressive disease of the navicular bone and surrounding soft tissue structures (bursa, ddft, ligaments)

back conditions in the horse

-fractures (withers)
-kissing spines
-soft tissues (muscle/ligament strain)
-sacro-iliac pain
-osteoarthritis (articular process joints)
-"false" back conditions
*deformities
*spondylosis

management of the horse with back pain

-controlled exercise programme
-NSAIDs
-physiotherapy
-schooling/rider issues
-alternative therapies

body systems to investigate in a horse presenting with poor performance

1 - musculoskeletal (73%)
2 - respiratory (24%)

DDx for hindlimb lameness in an immature small breed dog

-patellar luxation
-avascular necrosis of the femoral head

grading system for patellar luxation

1 - patella in groove, can be displaced but returns spontaneously
2 - patella in groove, can be displaced and remains so until replaced in groove
3 - patella out of groove, can be replaced but spontaneously luxates again
4 - patella out of groove and cannot be replaced

most common surgical treatment for patellar luxation

tibial torsion/rotation repair by tibial tuberosity transposition

how to Dx patellar luxation

-on physical exam
-try to push patella medial/lateral with index finger and thumb while extending stifle
-if permanently luxated, follow patellar ligament up from tibial tuberosity to find patella, try to replace it in the groove

DDx for swollen joints (equine)

-osteochondritis dissecans
-osseous cyst-like lesion
-physitis
-septic polyarthritis & osteomyelitis
-Salter-Harris fracture
-patellar luxation

joints most commonly affected by OCD (horse)

-hock (tarsocrural)
-stifle (femeropatellar)
-fetlock (metacarpophalangeal)

most common site for osseous cyst-like lesions in the horse

stifle joint (medial condyle of distal femur)

compare and contrast septic polyarthritis in foals vs. adults

(foals)
haematogenous spread after ingestion or from distant septic focus
(adult)
spread from adjacent infection, wound, iatrogenic

synovial fluid sampling considerations

-use aspetic technique
-perform cytology, look at WBCs (especially neutrophils) (EDTA purple top tube)
-check proteins (red top tube)
-culture +/- sensitivity

valgus

outward angulation ><

varus

inward angulation <>

management of angular limb deformities

-conservative if normal ossification (box rest, foot trimming/extension, diet restriction) [splint/cast if incomplete ossificaiton]
-surgical (slow or speed up growth with pins/wires through physes; corrective ostectomy)

flexural limb deformity aetiopahogenesis

increased joint flexion due to musculotendinous unit being too short for boney components of limb (contracted tendons) [sagittal plane]

treatment principles for flexural limb deformity

-stretch affected musculotendinous unit (physio, farriery, splint/cast)
-relax musculotendinous unit (oxytet, analgesia, splint/cast, treat underlying ortho. diz.)
-transect check ligament, tendon

common joints for flexural deformity

-DIP <box foot> (stage 1 and 2) - [cons. mgmt. or salvage check ligament/DDFT] respectively
-fetlock <straight leg> - [cons. trt. extend toe/raise heels, fetlock brace] or [Sx. trt. superior/inferior check ligament desmotomy]

flexor tendon laxity treatment

-mild > exercise and supportive care
-severe > light bandage, rasp heel, extend heel shoe

most common site for forelimb disease

elbow

considerations for arthrodesis

1) functional angle of joint
2) cancellous bone graft to speed healing
3) rigid internal fixation with compression

commonest neoplasm of forelimb

osteosarcoma @ proximal humerus (distal radius 2nd)

DDx for multiple limb lameness in the dog

-multiple trauma (RTA)
-digit/pad injuries
-developmental problems (bilateral)
(young)
-nutritional disease
-panosteitis
-metaphyseal osteopathy
-bone cyst
(adult)
-Marie's disease
-hypervitaminosis A (cat)
(all ages)
-immune based polyarthritis

causes of septic arthritis

-wounds
-iatrogenic
-spread from other infections (blood, or adjacent sites)

investigative techniques for septic synovitis

-distension test (inject saline to find draining tract)
-radiography (+/- contrast)
-ultrasound
-synovial fluid sample
-bacteriology

treating septic synovitis

-flush joint with saline arthroscopically - >10L sterile Hartman's
-local and systemic antimicrobials
-general wound mgmt/bandaging/rest
-tetanus prophy.

synovial fluid warning limits for septic synovitis

> 10 x 10^9 / L WBC, >= 90% PMNs

acute phase treatment of tendonitis

-box rest
-application of cold (hosing)
-firm and even bandage applied between cold therapy
-NSAIDs

PSGAG

polysulfated glycosaminoglycan

annular ligament syndrome

restricted SDT and DDFT within fetlock tunnel
-desmitis of annular ligament
-chronic synovitis of tendon sheath
-SDF or DDFT injury
-SQ fibrosis
-causes: strain, direct trauma, septic synovitis

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