Dog and Cat 7 Flashcards
Hereditability index for elbow dysplasia and how related to screening programs
- Heritability index appears to be quite low
- Heritability indices are not available for each of the four manifestations of the condition
- Fragmentation of the coronoid process (FCP)
- HI 0.06 - 0.24 - VERY LOW - will this screening program work???
What is involved with the radiographic screening for elbow dysplasia
- > 12 months of age
- Single FLEXED MEDIOLATERAL PROJECTION of both elbows
- Radiographs must contain permanent patient ID and L/R marker, date when taken, and clinic where taken
Elbow Score allocated according to severity of secondary OA - Score allocated based on detecting secondary osteoarthritis
○ osteophyte formation on proximal margin of AP
○ sclerosis at base of MCP
○ Sclerosis of ulna trochlea
○ osteophyte formation on radial head, humeral condyle, medial humeral epicondyle - Grade 0, 1, 2, or 3
Hip dysplasia what is it, cause, breed and heritability
= OA caused by joint laxity
- Inherited condition
- High prevalence among GSD, Golden Retriever, Labrador Retriever, Newfoundland
- Virtually unrecognised in breeds such as Greyhound and Borozoi
- Polygenic trait, with phenotypic expression strongly influenced by environmental factors
- restricted feeding resulted in lower prevalence of OA and later onset of clinical signs
- Heritability estimates for Hip Dysplasia range from 0.2 to 0.6
what does the radiographic screening of HD and list the 2 main screening programs
- on detecting joint laxity &/or secondary OA
- Accurate patient positioning is crucial for repeatability of assessments - GA or heavy sedation required
- Radiographs must contain:
○ permanent patient ID
○ L/R marker
○ date when taken
○ clinic where taken
Screening programs
1) ANKC CHEDS
2) PennHIP scheme
ANKC CHEDS what is it, what age, how to ensure positioned correctly and how to score what score used for
One of the 2 screening programs for hip dysplasia
- Relies on the ‘hip extended’ projection
- Dog must be >12 months of age
- Features to check for good positioning:
○ include pelvis and stifle joints
○ obturator foramen similar size
○ femurs parallel to each other
○ femurs parallel to table
○ patellas superimposed over the femoral trochlea
- Score = sum of scores attributed to nine key indicators of joint laxity and osteoarthritis
○ Joint laxity : Norberg angle, subluxation, rounding of acetabular margin
○ OA : osteophytes, enthesophytes (‘Morgan’s Line’), sclerosis, shallow acetabulum, modelling of femoral head & neck, flattening of dorsocranial acetabular margin
- Each hip scored out of 53, total of 106 per dog
- Score of a dog is compared to the breed average - worse than average -> probably don’t breed from
PennHIP scheme what is it, what does it rely on, positioning, taken by who, how old and other important factors
- Relies on the ‘distraction’ view
- hip distraction
○ Extending the hips causes spiral tensioning of joint capsule - masks laxity
○ Distraction techniques reveal maximal laxity of the hip joint - Relies on distraction of the coxofemoral joints, where a fulcrum force is applied to the hip joints to reveal the maximal passive joint laxity. This is achieved by placing the dog in dorsal recumbency, holding the hips in a neutral ‘stance’ angle, placing a radiolucent fulcrum
- Only taken by trained & accredited vets
- Dog must be > 16 weeks
- MANDATORY submission of films
- DI > 0.3 -> increased risk of developing OA later in life
List 11 ways to compare CHD screening schemes
- ANKC CHEDS well established, widely used, and well supported by breed clubs
- Hip extended view easy to take
- Any vet can take ANKC CHEDS radiographs
- ANKC CHEDS has perceived slow progress in eliminating CHD
- Little concrete research/science behind the ANKC CHEDS
- PennHIP DI has higher heritability estimate than Norberg Angle or signs of OA (Leighton et al. 1998)
○ HI for NA : 0.43 - 0.46
○ HI for radiographic OA : 0.03 - 0.37
○ HI for DI : 0.46 - 0.92 - DI appears to be a more repeatable scoring method than the schemes based on hip extended view
○ more repeatable between evaluators
○ more repeatable within the one animal, over time - PennHIP can be performed from 16 weeks of age, ANKC CHEDS must be 12 months of age
- Mandatory submission for PennHIP scheme, voluntary submission for ANKC CHEDS
- PennHIP views are more technically challenging to perform, more personnel, close to primary x-ray beam
- Must be trained for PennHIP, accredited, and have purchased the patented ‘distractor’ device
Ultrasound for musculoskeletal imaging, what type of frequency used for different structures and what can you visualise and the 4 main things it is used for
- High frequency linear transducer >7.5MHz for superficial structures
- Low frequency curvillnear <5MHz for deep structures
- Can visualise the following
○ Bone surface
○ Synovium
○ Joints space
○ Menisci
○ Muscles
○ Dynamic assessment
○ Guided aspirates/biopsy
Used for with equine
1. Tendon and ligament injuries
2. Pelvis - hard to visualise in radiograph
3. Stifle joint
4. Septic joint
Tendon injury with ultrasound what is normal and what occurs with injury
Normal tendon - Discrete fibre packets ○ Linear striations in longitudinal ○ Dots in transverse Injuried • Altered size and shape • Reduced echogenicity (hypoechoic) - fluid in tendon shealth • Altered fibre alignment
Large tendon injuries seen with ultrasound prognosis and why, how to know if large
- Large lesions = poor prognosis ○ Haematoma leads to: -> Granulation tissue -> Fine fibre bundles -> Irregular linear striations - Need to measure lesion -> measure the tendon and the lesion -> what percentage of tendon is the lesion
Small animals how is ultrasound used for musculoskeletal injury
- Not used as commonly as in equine patients
- Soft tissue structures in shoulder
- Common calcaneal tendon injury (Achilles tendon)
Joints - Normal synovial fluid: anechoic
- Synovial tissue: hyperechoic
- Articular cartilage: hypoechoic
- Bone surface hyperechoic with profound distal shadow
- Can target the joint via ultrasound to get out fluid and to put in medications
Meniscal injury
Ultrasound muscle what is normal and injury and disease
- Hypoechoic with internal hyperechoic striations
- Injury
○ Enlarged, disrupted fibres -> oedematous
○ +/- pockets of fluid - Fibrosis
○ Reduced size
○ Increased echogenicity
What is another important function of ultrasound and the 5 limitations
Foreign body identification - Especially grass seeds -> can dug up into soft tissue - Direct clinician to where it is Limitations of ultrasound 1. High quality machine required 2. Operator dependent 3. Limited information on bone lesion 4. Other modalities have increased sensitivity 5. Can't access some areas -> lungs
Sctintigraphy what is it mainly used for and what excellent and poor with, list the 4 main limitations
Mainly used for: - Equine lameness investigation - Some small animal applications - Excellent sensitivity for bone lesions - Spatial resolution poor Limitations 1. Referral institutions 2. Radiation licensing requirements 3. Low spatial/anatomic resolution 4. Poor specificity
Sctintigrahy what are the 3 phases in image acquisition and what can you assess in each stage
- Vascular phase
- Acquired immediately - as injected IV
- Assess blood flow
- Can be used in limbs where tourniquet -> is there blood flow to the distal limbs? - Soft tissue phase
- 5-10mins after injection
- Increase uptake may be due to trauma, infection, rhabdomyolysis
- Sensitive but NOT SPECIFIC - Bone Phase
- 2 hours pot injection
- Increase uptake in areas of increase bone turnover
- Screening for skeletal metastases
Computed tomography advantages and limitation especially with Equine CT
- Superior detail of bone and soft tissue
- More sensitive for bone loss
- Eliminates superimposition
- Improved lesion characterisation with reconstruction in different planes and 3D reformats
Limitations of Equine CT - Cannot get whole body within -> head and distal limb
- Need special table to hold the weight of the horse
What are the 6 main reasons to use CT for musculoskeletal injuries
- Elbow dysplasia complex
- Equine condylar fracture
- Foal osteomyelitis
- Pelvic fracture - BEST FOR THIS
- Foreign body - may have multiple draining tracts within the soft tissue
- CT guided biopsy especially in vertebrae and skull
MRI what is it goof for and limitations
- BEST soft tissue detail
- Good for detecting bone lesions
- Commonly used in humans
- Increased popularity for assessment of equine foot
- Underutilised in small animals
Limitations of MRI- Very expensive
- Limited availability
- Long scan times
- Usually required GA
What are the 3 main uses of MRI
- Canine shoulder - damage to the soft tissue around the bones
- Hip luxation - soft tissue surrounding the hip resulting in unstable hip joint -> luxation in and out
- Muscle injury -> muscle change
Osteochondrosis define, pathogenesis and main cause
- A focal defect in endochondral ossification in articular-epiphyseal growth cartilage
Pathogenesis
§ At least one secondary ossification centre generally at proximal end
□ Has junction with articular cartilage -> WHERE ISSUE IS IN THIS CASE
® Bone is meant to take over the articular-epiphyseal growth cartilage leaving only the permanent articular cartilage left - DOESN’T OCCUR
Cause - Anatomic factors - failure of blood supply locally
In terms of osteochondrosis what happens for the failure of blood supply
- Blood supply -> most cartilage is avascular
○ Permanent articular cartilage = avascular
○ Articular epiphyseal growth cartilage = vascular
§ THEREFORE -> vascular disruption leading to cartilage necrosis can occur in this region
□ Necrotic -> no hyperkeratotic chondrocytes -> not sending signals and preparing the region to endochondral ossification - Necrotic/retained cartilage results
○ Can resolve itself - no clinical manifestations
○ Other situations result in fissures from the articular surface -> leading to osteochondrosis dissecans -> joint mice
How would you best localise the problem within the limb and once localised what do you do next, if suspect OCD what best to diagnose
○ Orthopaedic examination -> BEST FOR LOCALISATION
- Radiography - need to always radiogrpah contralateral limb
Arthroscopy (DIAGNOSE AND TREAT THE JOINT)
What is the best radiographic view for lesion affected lateral trochlear ridge, whick joints tolerate OA best and when would you do a total elbow replacement
□ Flexed craniocaudal or dorsolateral plantar medial views -> uncommon
- More proximally joints tolerate OA best
- Total elbow replacement - NOT POINT UNLESS BOTH LATERAL AND MEDIAL CONDYLE AFFECTED
What are the 7 main complications of fracture repair
1) delayed union
2) malunion
3) non-union - viable and nonviable
4) osteomyelitis
5) open fracture and infection
6) implant fracture
7) refracture after implant removal
Delayed union define, and how is it defined and treatment
- Fracture where healing is progressing more slowly than expected
○ Define
§ young - 10 weeks should heal - if not delayed union
§ Older cat - 10 weeks not healed, normal - Intervention may be required to prevent nonunion or wait and see
Treatment: - Monitoring healing by sequential radiographs
- Revision of the stabilization - Rigid fixation
- Adding agents to improve healing ability:
- Cancellous bone graft, DBM, BMPs -> Osteoinduction
○ Add agents to improve healing ability
Malunion define, 4 main types and what may result in
- Healing of the bone due to initial malposition or malalignment during the fracture repair or early implant failure and eventual union
- Four types:
1. Frontal – varus/vargus
2. Axial - rotational -> when bandaging and the limb rotations
3. Sagittal – pro-/recurvatum -> opposite way to what is normal or what you want
4. Shortening - 10% difference in length between right and left limb well tolerated - Varus/vargus, rotational deformity and curvatum may produce secondary change
Malunion what are the consequences in mandibular/maxillary, pelvic and long bone fractures and treatment
- Mandibular/maxillary fractures - malocclusion of the mouth
- Pelvic fractures - constipation, dystocia
- Long bones – malalignment, OA, tendon/ligament damage due to abnormal weight
Treatment - CORA
- Stabilisation
○ Plates/screws
○ ESF - Open or Closed wedge
- CT and 3D printing
Non-union define and the 2 types with types within
- Fracture where healing has ceased and fracture healing is not possible without some form of intervention
○ Just filling in the gap with fibrous tissue
Viable non-union
1. Hypertrophic non-union - considerable callus present
2. Moderately hypertrophic non-union - moderate callus visible
3. Oligotrophic non-union - no callus but still viable cells present
Nonviable non-union
1. Dystrophic non-union - radiographic appearance similar to oligotrophic non-union but no blood supply so no viable cells
2. Necrotic non-union - presence of a sequestrum surrounded by involucrum (reactive new bone
3. Defect non-union - fracture gap is too large
4. Atrophic non-union - resorption of the fracture ends leading to rounding of bone ends and osteoporosis
List the 5 main causes of non-union
1) instability
2) stress protection
3) too much gap
4) poor blood supply
5) infection
Describe how instability and stress protection leads to non-union and what type of non-union do they lead to
Instability – hypertrophic nonunion
○ Caused by fracture repair that does not provide adequate stability
○ Too much stress and strain leads to formation of fibrous tissue
2. Stress protection – atophic non-union
○ Some strain is necessary to stimulate stem cells to differentiate so if the fracture repair is too rigid this doesn’t occur
nterfragmentary strain <1%
- Typically an antebrachium of toy breed dogs due to large implants relative to its small skinny radius
○ Too rigid stabilisation cause osteopenia of bone underneath and atrophic non-union of ulna
Describe how too much gap, poor blood supply and infection leads to non-union and which type of non-union do they lead to
Too much gap – defect non-union
○ 1.5x the diameter of the bone -> will not unite at this point
Poor blood supply – delayed union, malunion, defect, necrotic and atrophic non-union
○ Invasive surgical approach, lack of soft tissue coverage (antebrachium of toy breeds), loose implants especially cerclage wire
○ Lack of soft tissue coverage (antebrachium of toy breeds)
Infection – necrotic non-union
○ Sequestrum and biofilm - infection can lodge into this areas -> prolong the inflammatory phase
○ Bone can heal in the presence of infection
Treatment of viable non-union
- Address the underlying problem
○ Remove loose implants
○ Improve stability if secondary to instability
○ Destabilise if due to stress protection
○ Treat infection if present - Remove fibrous tissue from the fracture site and restore access to the medullary canal via drilling/reaming
- Apply autogenous cancellous bone graft or allografts, DBM, rhBMPs
○ Provides factors -> however if infection osteoblasts may not survive
What are 4 ways to prevent non-union
- Staged destabilisation
- Circular or hybrid ESF
- Use of titanium implants instead of stainless steel
- Locking system and MIPO to preservation of surrounding soft tissue and vascularity
Treatment of nonviable non-union
- Treat underling problem -> Remove sequestra
- Remove fibrous tissue from the fracture site and restore access to the medullary canal via drilling/reaming
- Application of autogenous cancellous bone graft or similar
- Rigid fixation and compression typically with a plate
- If a large defect is present can be addressed by:
○ Cortical autograft or allograft, DBM, rhBMPs
○ Bone transport – distraction osteosynthesis
Osteomyelitis as a complication of fracture repair what damage does it lead to and 3 main clinical signs
- The damage associated with osteomyelitis and its response to treatment is influenced by:
1. The viability and stability of the bone
2. The virulence and antimicrobial sensitivity of the organism
3. The condition of the soft tissue envelope - Clinical signs:
○ Excessive/cloudy/purulent discharge
○ Pyrexia
○ Systemic signs
Open fracture and infection as a complication of fracture repair what leads to and how occurs
- Tissue trauma and ischemia
- Subsequent bone necrosis
- Biofilm formation
○ Conditioning film on top of the internal fixation
○ Glycocalyx -> gel like structure that is the problem -> produced by the bacteria that live within
§ Mechanical barrier to antibiotics
§ Low activity
§ Harsh environment
clinical signs and treatment for acute fracture repair infection
Acute: - Localised swelling and localised pain - Frequently febrile and various systemic illness including lethargy and inappetence - Systemic inflammation (leucocytosis) Treatment: - Debridement - Rigid stabilisation - Appropriate Abs - Better prognosis than chronic
clinical signs and treatment for chronic fracture repair infection
- Localised disease
- Rarely present with systemic changes (draining tracts and lameness)
Treatment: - Tissue ischemia is the major issue
- Removal of infected bone, soft tissue, implants
- Appropriate Abs (i.e., localised AB impregnated PMMA)
Soft tissue coverage and blood supply
Implant failure define and the 3 main causes
- Inadequate implant selection or application
- A race between fracture union and the implant failure during healing time
Causes
1. Fatigue failure:
○ repetitive lower loads
○ Most common
2. Overload failure:
○ single large load more than the yield stress of the implant or bone implant interface
3. Biological failure (secondary):
○ Tissue trauma and ischemia due to initiating injury or an inappropriate surgical technique
○ poor postoperative management (inadequate confinement of a patient)
Implant failure treatment
- Implant removal, revision of construct and consideration of the local healing environment
- Improve healing environment by attempting to improve the blood supply of the region
- Stimulate bone formation through Cancellous bone grafts or addition of exogenous products such as DBM and BMPs
Refracture after implant removal what are the 2 main factors that lead to this and prevention
- Biological factors
○ Ischemia and infection - Mechanical factor:
○ Stress protection under an area of a plate, open bicortical screw holes - most important predisposing factor
○ Premature removal of the implant - Rigid plate fixation has been associated with stress protection and subsequent bone loss
- The most important treatment is to prevent a refracture from occurring
○ External coaptation and exercise restriction to prevent excessive loads on healing site
What are physeal fractures different to diaphyseal fractures
- High prevalence in younger animals
- If not recognised or treated early, results can be devastating
○ Pain
○ Angular limb deformities
○ Joint incongruity
○ Loss of function - Growth plates contribute to 75-80% to final bone length
when can physeal fractures occur
- In dogs, most longitudinal bone growth takes place between 12 and 26 weeks of age
- Growth plates have most rapid rate of bone growth and endochondral ossification during this time
- After this period bone growth continues at a much slower rate and then ceases completely
- Growth plates mineralise at predetermined times. Usually between 4 and 12 months
Why do fractures occur at the physis commonly in young animals
- The physis is weaker than surrounding bone and ligaments
- Weakest part of the physis is at the junction of the hypertrophic zone and the zone of calcification
- Avulsion or shearing forces
- If damage to cells in the proliferative zone occurs, the physis can be bridged by bone and growth arrest
○ Symmetric or asymmetric angular limb deformities
Salter-Harris Classification what are the 6 main types
For physis fractures
fracture through…
Type 1 - straight through physis
Type 2 - metaphysis and physis
Type 3 - epiphysis and physis - into joint (Articular)
Type 4 - physis, epiphysis and metaphysis (articular)
Type 5 - compressive physis injury
Type 6 - peripheral injury leading to bridge formation on one side
Healing of physeal fractures which heals rapidly and how do the others heal
- Type I fractures: heal rapidly by continued growth of physeal cartilage and metaphyseal cartilage formation
- OTHERS:
○ If growing cells are damaged in the reserve and proliferation zones, growth of physeal cartilage does not occur and endochondral ossification proceeds
○ Bone is formed in the fracture gap, resulting in premature closure of the growth plate
Malalignment of the physis leads to bridging of the physis with bone
Physeal fracture repair surgery advantages and disadvantages
ADV - Good blood supply - Rapid healing - PROGNOSIS good DIS - Limited bone stock - Soft bone - Juxta-articular - Potential for ongoing distraction forces on repair
Proximal tibial physeal fractures how treat and possible consequences
- Simple tibial tuberosity avulsion alone treated with two K wires +/- tension band wire
○ Regardless generally results in physis closure -> young dogs can lead to destabilisation of tibial tuberosity which is generally tolerated well clinically - Proximal tibial physeal fractures can be treated with cross pins driven from epiphysis medially and laterally to exit opposite cortex of the tibial shaft
○ Asymmetric growth plate closure can result in angular limb deformity which owner should be warned about
Intra-articular fracture surgicial principles and what need to advise clients
- Repair ASAP -> ideally within 24 hours as post-injury muscle contracture, fibrosis and resorption hampers reduction
- Gentle tissue handling
- Perfect reduction of intra-articular component
- Rigid stabilisation with Internal fixation is required to allow early return to weightbearing
- Advise clients that some degree of Osteoarthritis will develop
Humeral condylar fracture causes in young and adult patients, 2 types and surgicial repair
- Occurs in
○ young patients -> often associated with trauma
○ adults -> often secondary to incomplete ossification of the humeral condyle (IOHC) -> therefore always radiograph the contralateral limb - Can be
○ Unicondylar: lateral side is affected more commonly
○ Dicondylar: Y or T fractures involved both lateral and medial epicondylar crests - Surgical repair
○ Transcondylar lag screw
○ Epicondylar crests are repaired with either K wires (young/small patients), lag screws or plate and screws
○ Humeral Y and T fractures require high demands with medial and lateral approaches needed
Radial carpal bone fracture what are the 2 main presentations
§ Chronic insidious mild lameness with no history of trauma
□ Breed depositions, fractures often minimally displaced
□ Typical fracture patterns -> dorsal slab, Comminuted, T-shape
§ Trauma- associated with right in racing greyhounds
□ Often oblique, midbody and minimally displaced so difficult to diagnose
Carpal bone fractures 2 main treatment options
Treatment
§ Conservative
□ NSAIDS for OA
□ External coaptation -> unsure on whether causes advantage
§ Surgical
□ Lag screw for simple fractures from dorsally
□ Partial or pancarpal arthrodesis (surgical immobilization of a joint by fusion of the bones.
Accessory carpal bone fracture what most common in and the 5 types
○ Most common with racing greyhounds in right carpus if they race counterclockwise typically on a turn or if bump into another dog
5 types
§ Type 1: affects distal articular surface, most common type (67%)
§ Type 2: affect proximal articular surface
§ Type 3: Affects distal/caudal surface: avulsion fracture of accessorometacarpal ligaments
§ Type 4: Affects proximal/caudal surface: avulsion fracture of flexor carpi ulnaris
§ Type 5: Comminuted, non-surgical, coaptation, poor prognosis
Accessory carpal bone prognosis for greyhound racing and surgical repair
○ Types 1-4 prognosis is good and 90% of dogs will return to racing
○ Surgical repair
§ Excise small fragments
§ Reattach larger fragments with lag or positional screws (1.5 to 2mm)
§ Support with external coaptation
central tarsal bone fracture what breed affect, what can result in, 3 types and treatment for each
Seen almost exclusively in racing greyhounds, affects right tarsus
○ Loss of buttress on the medial side often leads to fractures of the 4th TB and the calcaneous
○ 5 types and how repaired
§ Type 1: non displaced dorsal slab fracture. Repaired with lag screw
§ Type 2: displaced dorsal slab fracture. Repaired with lag screw
§ Type 3: large displaced medial fracture. Repaired with lag screw
§ Type 4: Medial slab fracture with a dorsal slab fracture, Repaired with 2 lag screws
§ Type 5: Comminuted fracture. Non reconstructible, treated with external coaptation.
Metacarpal/metatarsal fracture treatment what are the 2 main options and describe
- Conservative management - cast or palmar splint to mid antebrachium
- Surgery
- Miniplates (typically applied to bones 3 and 4 only)
- IM pins
§ Dowel pinning -> placed retrograde from the fracture site
§ Normograde distal -> placed via slot burred in dorsal aspect of distal metacarpal
- IM pins + ESF
□ Typically centre threaded full pin through base of metacarpals
- Typically all surgical repairs are supported with a palmar splint for 4-6 weeks
Metacarpal/metatarsal fracture surgery what is important to consider/principles and prognosis
- > 2 bones affected
- Metacarpal/metatarsal bones 3+4 affected
- Articular
- Fragments displaced >50%
- Large breed/athletic dogs
- Fractures affected base of MC 2+5
Prognosis - excellent for simple fractures
Digit fractures what are the 2 main repair options
- External coaptation
- Surgery:
- Small bone plates if diaphyseal.
- Lag screw/TBW for avulsion articular fracture
- Excisional arthroplasty
- Always supported with coaptation initially
Digit amputation
Digit luxations treatment options
- External coaptation
- TA ESF with free form connecting bar
- Arthrodesis (dorsal bone plate)
- Technically difficult (contouring, implant placement), poor ST coverage, interferes with extensor tendons
Post operative care for physeal fractures
- Strict rest for 6-8weeks
- Appropriate pain relief for 5-7 days post-op
- Implant removal around 4-5 weeks for physeal fractures
- Followed by another 3-4 weeks of strict rest
- Splint/case for additional stabilisation if required for MC/MT fractures (replace weekly)
- Re-check x-rays at 6-8 weeks
- Then gradual return to normal activity and physiotherapy
Pelvic fracture what is needed to displace pelvic fragments and soft tissue consideration
More than 3 fractures in pelvis to displace the pelvic fragments Soft tissues consideration 1. Nerves 90% with ilial fracture ○ Neuropathy is common § Sciatic nerve assess -> pinch the toes and want to see for the withdraw reflex § Femoral nerve -> patellar reflex ○ Urinary/fecal problem 2. Pelvic canal ○ urethra, colon/rectum ○ Urinary tract injury 40% 3. Muscles: ○ Gluteal/biceps/sartorius - ilium ○ Hamstrings - ischium ○ Adductors - pubis
What are the main indications of pelvic fracture repair surgery
ALL INVOLVED IN WEIGHT BEARING AXIS • Acetabulum • Ilium • Sacrum Other indications: • Narrowing of the pelvic canal >50% • Future planning for breeding (females) • Prepublic tendon damage - abdominal hernia • Too painful – nerve impingement • Ischium avulsion fracture – attachment of hamstrings
Pelvic fracture what are indications and examples of conservative management
○ Indications
§ Non-weight bearing axis
§ Stable fracture
§ Less painful
○ Examples
§ Cage rest
§ NSAIDs and pain relief
§ Physio/hydrotherapy
§ Bladder care - manually express or urinary catheter if urinary function loss
○ Nursing – challenge for aggressive dogs, large/giant dogs – may not be suitable for conservative management
§ If within the hospital -> charging for high labour intensive
Pelvic fracture surgical management what better for, what use and when urgent or can delay the surgery
- Better recovery with surgical management so would do with large athletic dogs or anyone that wants to do it
- Use lag screws
- Relatively urgent
○ Acetabular (articular) fracture
○ Weight bearing axis
○ Too painful (nerve impingement) - Delayed surgery
○ Pelvic canal narrowing >50%
○ Wait for soft tissue recovery (particularly neuro/urinary function)
○ Other injuries or diseases, unstable for anaesthesia
Assessment of pelvic fractures what are the 3 important examinations techniques
- Orthopaedic exam
- Landmarks of pelvis -> triangular landmarks will move relative to each other
○ Iliac crest
○ Greater trochanter
○ Ischial tuberosity - Neurologic examination
- Diagnostic imaging
- Radiography
○ Readily available
○ 2D - superimposition - limitation
○ Orthogonal view or multiple views may be necessary
- CT
○ Useful for complex fracture
○ 3D reconstruction
○ More detail of fractures
In terms of neurological exam with pelvic fractures what nerves worried about and what muscles/organs do they innervate
- Sciatic – tibial, peroneal
- Pudendal – caudal rectal, bladder
- Pelvic - bladder
- Femoral – saphenous
- Cauda equine – tail tone
Sacroiliac luxation uni or bi most common, what seen on radiograph, what needed to occur, pssible complications
- Often bilateral (23%)
- Seen as a step on VD radiographs (red arrow)
- Must have concurrent other pelvic fractures (at least 3 locations)
- Sciatic and other peripheral nerve impingement can occur
Sacroiliac treatment 2 main options and when choose which
- Want to stabilise surgically within 4 days if possible
- Conservative treatment-> Cases with subluxation, good limb function, and no neuro deficits may be candidates
- Surgery:
○ Lag screw(s)
§ At least 60% of sacral width - if less more stress on screws -> increase chance of luxation
○ Trans-ilial
○ bolt/pin - Aim to get screw in S1 sacral body which is a small target area (1 cm2 in a 25 kg dog)
Ilial fractures what most common, possible complications and treatment (which most common and alternatives)
- Usually long-oblique
- Screw loosening common (esp. cats)
- Displacement can lead to pelvic canal narrowing
○ Problematic in breeding females
○ Constipation in cats (>50% narrowing)
Treatment - Don’t want high compression
- Lateral plating most common
○ Screw loosening is common - Alternatives:
○ ESF (uncommon) - if have extensive skin wounds
○ Interfragmentary screws
○ Ventral (tension) plating
○ Composite (screw/wire/PMMA)
○ Dorsal plating (in cats)
Acetabular fracture what is important about these, what leads to and treatment
○ Theoretically cranial 2/3 must be repaired -> weight bearing area
○ OA develops regardless
○ Caudal 1/3 should also be addressed
Treatment
- Small patients with nondisplaced fractures may tolerate conservative
- Surgery:
○ Complicated surgery to get to the site of the fracture
○ Acetabular/reconstruction plates
○ DCP - dynamic compression plate
○ Locking plates (esp. SOP)
○ Composites (screw/wire/PMMA)
Sacral fractures how to describe, how painful, treatment and prognosis
- Abaxial: lateral to the sacral foramina and/or involving the spinous processes
- Axial: medial to the sacral formina and ventral to the spinous processes
- Often very painful
- Surgery recommended if unstable/painful or neuro deficits
○ Surgery:
§ Typically 1-2 screws placed similarly as for SI luxation - Prognosis good, most neuro deficits will resolve but if persistent urinary incontinence euthanasia may be required
Pubic floor fracture (ishium and pubis) what important about it, how to reduce and repair
- Reduction of other fractures with internal fixation (eg. Ilial fractures and SI luxation) typically results in significant improvement in reduction of pubic/ischial fractures
- NOT part of weight bearing axis
- Two exceptions:
○ Ischial tuberosity avulsion – hamstring muscle origin
○ Pubic fractures associated with abdominal rupture - Repair recommended in athletic and working dogs
- Repair:
○ Lag screws
○ Wiring
○ TBW
Mandibular and maxillofacial fractures what is the main cause and other causes
Trauma
- Motor vehicular trauma
- Fight
- Fall (high rise syndrome - more than 3 stories
Pathological fractures:
- Periodontal disease, particularly in small breed dogs
○ Can be infected -> osteomyelitis
- Iatrogenic fractures during procedures such as dental extraction
- Neoplasia
Mandibular and maxillofacial fractures diagnostic imaging
- Easy to recognise when displaced
- May need multiple views
- Superimposition of structures
- CT useful for minimally displaced/complex fractures
What are important considerations with mandibular and maxillofacial fractures
- Maxilla and mandibles - good blood supply, heals quicker than long bones
- Often multi-trauma
- Commonly open fractures (oral bacteria prophylaxis)
- Occlusion important for mastication
- Tube feed to bypass mouth
○ Pharyngostomy
○ Transmylohyoid intubation - Tooth roots - avoid with implants
Maxillofacial fractures what good and bad for, if surgery required and what would you do
- Very thin bone: Bad for Implants
- Good vascularity: Good for healing
- Some fractures are stable due to rows of buttresses that distribute forces
- Broadly attached to skull via medial, lateral and caudal buttresses - often surgery not required
- IF want to do surgery -> thin cortex result in benefits with using locking screws
Mandibular fractures what side would you place the plate iis this cimplicated, what need to avoid and what shouldn’t be used
- Forces applied by the masticatory muscles
○ Alveolar margin is the tension site -> should place the plate on this side - CANNOT PLACE ON THIS SITE
§ May need to use interdental wiring, external fixation as plating hard
○ Ventral margin is the compression site - Avoid teeth, so usually small implant (miniplate or wire) to avoid roots -> do not remove teeth if stable as can contribute to stabilisation
○ Teeth roots more dense rostrally with incisors compared to molars - Locking screws aren’t beneficial as then angle is fixed
Mandibular symphysis fractures
- Separation through the fibrous symphysis is common
- Especially common in cats with blunt force trauma to the head
- Encircling wire most common, passed with large gauge needle and twisted under the chin
Mandibular body fractures what can use to treat
- Tape muzzles ○ NOT able to be used for cats or brachycephalic dogs (insufficient muzzle for restraint) ○ NOT to be used for rostral fractures ○ Easier on long muzzle dogs - Interfragmentary wires - Intraoral splints - ESF - Miniplates (conventional/locking)
Caudal mandibular fractures treatment options
- Can be repaired with miniplates or interfragmentary wire
- Plates along crests to maximise bone thickness for screw purchase), not fossa
- Mandibular-maxillary fixation (e.g. dental bonding) -> cannot chew properly
Swellings in paws what probably the issue, how to treat, what can look like it and prevention
never underestimate a grass seed AND don’t always assume it is a grass seed
○ Sometimes lucky - local anaesthetics -> and use forceps
§ Sometimes may need to go to ultrasound
§ Warn the client -> can track up
○ Pododermatitis can be common in staphies and may look like grass seed -> biopsy to diagnose
○ Prevention -> trim the paws and lower forelimbs during summer
List possible diffeentials for entire paw swollen, hair loss on paw, hair loss plus suppuration and possible pain relief for these options
- Entire paw swollen - think cellulitis in cats, causes of bites, stings and trauma
- Hair loss on paws - white fluffy and brown stained hair think ATOPY
- Hair loss plus/minus suppuration - think demodicosis
○ Pain relief - buprenorphine orally, meloxicam, tramadol - if don’t like then foamy
Acral lick granuloma what common in what need to do to treat
- Common in dogs (generally larger breed), rare in cats
- Need to
○ Identify primary trigger
§ Older dogs -> underlying osteoarthritis
○ Treat the infection - generally secondary infection
○ Break the cycle
§ Can be psychological - medication, modification, management
List and describe 5 injuries that can occur to the pads
1) Cut pads - frustrating to treat
○ If deep suture but need large bites away from the wounds -> does take time to heal
2) Cracked, dry pads
○ Over exercise on inappropriate surface
3) Swollen, worm pads
○ If not exercising as much
4) Blisters and burns - painful - frequent pain relief, AB and bandage changes
○ Curiosity of the cat
5) Insect bites/stings - acute lameness and licking
○ Can be quite dramatic -> screaming
○ Run paws under cool water for 10mins can help to soothe
What are the 2 main pad diseases, how to treat
1) Plasmacytic pododermatitis (spongy pads) - again a cat problem, rare but once seen not forgotten
○ Generally respond to doxycycline and prednisolone
○ Diagnosis via clinical examination
2) Cutaneous horns, hyperkeratosis - proliferation of keratin - owner can think that their pet has grown an extra nail
Nails what are the 2 main issues and what need to be cautious of with trimming nails
- Torn broken nails are very common, other nail disorders not so common
- Beware of ingrowing dew claws or other ingrowing nails
○ Forelimbs keep the dew claws on - Trim nails with caution
○ Use your own judgement not the owners
○ Beware of the bleeding
§ As get older the quick gets longer
○ Older cats -> do not shed nails as well -> can dig into pads
What are the 6 main techniques for limb salvage
- • Amputation
- • Arthrodesis
- • Total Joint Arthroplasty
- • Excision Arthroplasty
- • ITAP
- • Oncologic Limb Sparing
Amputation what are the 7 main indicators
- Neoplasia
- Severe Fracture Comminution
- Severe Open Fractures
- Local Peripheral Neurologic Disease
- Failure or Complications of other appropriate treatment
- Owner financial concerns preclude other treatment
- Severe local OA poorly responsive to other therapy
Amputation what are some pre-op considerations and the goals
Pre-op considerations - Consider appropriateness - Identify poor candidates - Concurrent Disease: ○ Orthopaedic ○ Neurologic ○ Metastatic Oncologic Dz - Provocative testing for non-emergent amputation: ○ Non weight bearing sling - Simulate non-weight bearing in one leg -> to determine whether the animal will be fine with this • Goals: - Removal of limb/disease - Accurate and secure haemostasis
Amputation what occurs with partial amputation and what is important with haemostasis
Partial amputation: - Unnecessary burden of stump - No improvement in function - Unless prosthetic device used: ○ Challenges associated with ingrowth ○ Poor patient acceptance of external prostheses/braces Haemostasis: - Arteries ligated separately to veins ○ Veins before arteries – neoplastic ○ Arteries before veins – non-neoplastic - Double ligation / Transfixation ligation: ○ All Arteries ○ Large veins
What are the 2 main amputation techniques for the thoracic limb, what do they involve, prognosis and which recommended
1) Gleno-humeral disarticulation: ○ Leave the scapula ○ Muscle atrophy results in prominent acromion -> not recommended ○ Decubital ulceration 2) Forequarter Amputation - recommended ○ Only tendons and muscles are cut ○ Neater appearance post-operatively ○ Reduction risk ulceration ○ prognosis is good (hindlimb better)
What are the 13 steps in amputation of the forelimb
- Tear drop incision
- Transect scapular muscles
○ Trapezius (cranial)
○ Omotransversarius (cranial)
○ Rhomboideus (dorsal)
○ Serratus ventralis (medial) - to remove scapula from the body wall - Retract scapular laterally
- Identify brachial plexus and major vessels
- Triple ligate axillary artery and vein separately
- Sharply transect brachial plexus nerves –bupivicaine
- Caudal to cranial
§ Median, ulna, radial, axillary, subscapular, suprascapular
○ Transect muscles
§ Brachiocephalicus
§ Deep and superficial pectorals
§ Latisimus dorsi - Large dead space
- Good hemostasis
- Lavage 0.9% NaCl
- Analgesic catheter
- Deep and superficial muscles closure
- Subcutaneous closure
- Skin staples or sutures
How to perform a triple ligate of the axillary artery and vein when amputating the forelimb
- Encircling ligature
- Transfixing ligature - distal to the transfixing (down from the heart)
- Encircling ligature
- Transect between transfixing and distal encircling ligature
What are the 2 techniques for pelvic limb amputation what is the difference
1) Mid-femoral: ○ Technically easier ○ Muscle bellies must cover stump 1. Approach the large vessels first - femoral artery (medial location) -> incision at distal femur at level of patellar caudally to tuber coxa -> ligation 2. Incision of the muscles -> their insertions or bellies if need be 2) Coxofemoral Disarticulation: ○ Recommended for femoral neoplasia ○ No stump to cover ○ Slightly more demanding
Amputation outcomes and complications
Outcomes
- Tolerated with good to excellent function in most dogs and cats (irrespective of size):
○ Gait modification
○ Shift in centre of gravity and paw placement
○ Better in hindlimb then forelimb -> greater weight bearing is on the forelimbs
Complications:
• Seroma
• Infection
• Dehiscence
• Phantom pain? - not very common in animals
- In order to avoid give pre and post-op pain relief of ketamine
Arthrodesis define and what are the 6 main indications
- Deliberate permanent bony fusion of a joint Indications: 1. Chronic osteoarthritis 2. Instability: joint luxations ○ Acute trauma ○ Degenerative disease 3. Local inflammatory disease 4. Neuropathy? 5. Irreparable articular fractures 6. Complications from fracture repair
Arthrodesis goal and principles
- Try to get back to Functional (standing angle)
○ Measure contralateral limb (if normal)
○ Tables for normal angles published for some breeds - Removal of articular cartilage - if not will get pain
- Rigid, stable fixation -> plate and screws via compression
- Autogenous cancellous bone grafting:
Arthrodesis what problem persists and which spots have greater instabiity
- Gait abnormalities will persist:
○ Advise owners pre-operatively
○ Aim for pain free, functional result
○ Compensatory mechanisms:
§ Increased flexion/extension in remaining joints of affected limb and contralateral limb
§ Functionally can have good movement just want be as normal - Sites subject to large forces:
○ Long lever arms
○ Adequate fixation:
§ Bone Plates
§ ESF (where bone plates undesirable) - More proximal sites = Greater disability:
○ Hip not arthrodesed all others can be done
○ Shoulder – compensation from articulation with thoracic wall musculature
Arthrodesis what are the 5 complications
- • Increased stress on surrounding joints
○ Pancarpal vs. partial carpal arthrodesis - • Non-union
- • Infection
- • Implant failure
- • Plantar necrosis - tarsal only
Shoulder arthrodesis indications and how apply
• Indications:
- Chronic OA secondary to OCD
- Mal-union, non-union of intra-articular fractures
- Chronic shoulder luxation including medial glenohumeral ligament instability
• Plate fixation:
- Thin scapular bone – longer plate for improve bone purchase
- Lateral aspect of scapula with twist to allow cranial application to humerus
- At least 4 screws above the shoulder
Elbow arthrodesis indications, how apply and complications
• Indications: - Severe OA secondary to: - Elbow Dysplasia - Trauma/ Luxation - Intra-atricular fracture - Premature distal ulnar physeal closure • Plate fixation: - Tension surface = caudal - Olecranon osteotomy & Reattachment • Complications: - Implant failure - Infection - Fracture
