Small animal MSK disease 7 Flashcards
With repair of a mandibular symphyseal fracture, what is the main criteria for determination of whether acute or reasonable repair has been achieved in small animals?
Whether or not the animal can close its mouth
Outline the method for repair of a mandibular symphyseal fracture in small animals?
Cerclage wire around jaw, just caudal to canines
Can place large needle to brace wire behind teeth
What are the main causes of maxillary fractures in small animals?
- Falling from a height
- RTA
List the methods used for fixation of maxillary fractures
- Interdental wiring
- Acrylic bonding of canines
- Plates (rare)
- External skeletal fixation
- BEARD (bi-gnathic encircling and retaining device)
Outline the use of interdental wiring for the fixation of maxillary fractures
- Wire between teeth to align maxillary fracture
- Apposes 2 sides of hard palate well
- Usually placed below gingiva and soft tissues of hard palate
Outline the use of acrylic bonding of canines for the fixation of maxillary fractures
- Acrylic resin on teeth, leaving mouth open 1cm, ensuring jaw aligned
- Anaesthetic required for removal
Outline the use of a BEARD maxillary fracture fixation
- Suture around mandible and maxilla, aligns teeth
- Prevents opening of mouth
- Mainly used in cats
Describe the clinical signs of a temporomandibular luxation
- Similar to maxillary fracture in presentation
- Inability to close mouth
What direction will the jaw deviate in a temporomandibular luxation in small animals?
Away from the site of the luxation
Outline the treatment of a temporomandibular luxation
- Place wooden dowel into angle of jaw as caudal as possible
- Apply dorsal pressure to rostral mandible
- Normally reduction is easily achieved with this
- Feed soft foods for several days
In which cat breeds is patellar luxation more common?
Pure breeds, e.g. Abysinnian, Devon Rex
Outline the clinical signs of patellar luxation in cats
- Unwillingness to jump
- Awkward gait
- Lax patella on palpation is not indicative unless showing clinical problem
Which cats are predisposed to cranial cruciate ligament rupture?
Obese cats, but rarely occur in isolation, mainly associated with trauma
What are the treatment options for cranial cruciate ligament rupture in the cat?
- Conservative treatment (preferred)
- Or using extra-capsular suture
Outline the treatment for total disruption of the stifle in small animals
- Surgery: extra-capsular suture + prosthetic collateral lig (+/- meniscectomy) or trans-articular skeletal fixator to maintain joint reduction
- Remove damaged menisci
- Stabilisation
Outline the management of a patellar fracture in cats
- Conservative or surgical
- Conservative preferred if not too distracted
- If surgical, use cerclage wires to capture and bring closer
Discuss the presentation of patellar fracture in young cats
- Often have retained deciduous canines (Knees and teeth syndrome)
- Also commonly fractures to other bones incl. tibia and calcaneous
Give examples of salvage procedures for MSK diseases in small animals
- Arthroplasty
- Arthrodesis
- Amputations (+/- prosthetics)
Give examples of indications for salvage procedures in small animals
- Severe osteoarthritis (arthroplasty, total hip replacement)
- Severe fractures
- Financial concerns
What is arthroplasty?
Surgical reconstruction of a joint
What are the types of arthroplasty available?
- Excision or replacement
- Partial or total
List the indications for arthroplasty in small animals
- Dysplasia leading to unmanageable juvenile pain
- Persistent luxation
- Non-reconstructable articular fracture
- Painful intractable degenerative joint disease
Discuss the outcome of excisional arthroplasty
- Pseudoarthrosis
- Pain free
- Instability of joint leading to abnormal movement
- Reduced ROM and regional muscle atrophy
- Mechanical lameness
- Outcome variable esp. in bigger dog
Where is excisional arthroplasty most commonly performed?
- Hip
- Occasionally in TMJ
Discuss the outcome of replacement arthroplasty
- Normal joint function
- But lifelong potential morbidity
Why does mechanical lameness occur with exciscional arthroplasty of the hip?
- Limb shorter
- When weight bears, femur will rise up due to lack of dorsal acetabular aspect
Describe the position of the cut for a femoral head and neck excision
- Insertion of the iliopsoas and the gluteals i.e. maintain greater and lesser trochanter
- Remove more of caudal neck (make cut perpendicular to neck)
Discuss the factors influencing the outcome of a femoral head and neck excision
- Larger = poorer outcome
- Temperament/fitness: fitter active individuals to better
- Age: younger to better
- More chronic = more muscular atrophy = poorer outcome
- Bilateral/concurrent: more difficult to manage, poorer outcome
- Owner compliance wth physiotherapy
In which species can arthroplasty, amputation or arthrodesis be performed?
- Arthroplasty: cats and dogs
- Arthrodesis: all small animal species depending on joint
- Amputation: dogs and cats (limbs, digits, tail), and small caged pets (limbs and tail)
In which joints can a replacement arthroplasty be performed in cats and dogs?
- Canine: hip, elbow, stifle
- Cat: hip only
List the indications for total hip replacement
- Any size dog/cat
- Esp. for active/working animals
- Ideally 10-40kg dog
- Intractable pain assocaited with hip dysplasia
- Perthes disease
- Compliant owner
- No previous hip surgery
- Good temperament
Identify the different types of total hip replacement implants
- Cemented (polymethylmethacrylate PMMA)
- Cementless (bone ingrowth)
- Hybrid systems
List the possible complications of total hip replacements
- Infection (surgical or haematogenous)
- Dislocation (esp. first 8 weeks)
- Aseptic necrosis of cemented systems as a result of technical error or cement failure, or accumulation of wear
Outline the management of total hip replacement complications
- Reassess
- Likely to need conversion to femoral head and neck excision
- If dislocation, can replace, but will likely re-luxate
Discuss the use of total elbow replacements in small animals
- Rare
- High complication rate 20%
- Commonly a bilateral disease
- Little can be done if fails, poor candidate for amputation
In which joints can arthrodesis be carried out?
- Carpal
- Talocrural
- Shoulder
- Stifle and elbow are poor candidates
Give an example of an indication for arthrodesis of the carpus
Hyperextension injury leading to rupture of palmar cartilage or palmar ligaments
Outline the principles of arthrodesis
- Absolute stability, ideally through compression
- remove cartilage from contact areas
- Contour opposing joint surfaces
- Cancellous bone graft
- Fuse at functional angle
- Provide temporary external support
Explain why a pancarpal athrodesis is better than a partial one
- Pancarpal means equal pressure on joints
- Partial will put more pressure on some joints
What are the possible complications of stifle or elbow arthrodesis?
- Leg left too long: scuffs nails on ground, must circumduct limb to move
- Too short: never puts foot on ground
List the indications for amputation in small animals
- Limb not salvageable (e.g. result of trauma, esp. if involving joints)
- Intractable pain
- Neoplasia (malignant, locally invasive)
- Failure of first line treatment
- Paralysis e.g. brachial plexus avulsion
- Financial reasons
List key factors to think about when considering amputation
- Presence of bilateral problem/other orthopaedic disease
- Body condition/weight
- Age
- Owner
- Temperament
Outline the general principles of limb amputation in small animals
- Cut bone short and leave excess skin and soft tissue to cover
- Peri-neural local anaesthesia, sharp incision through nerves
- Careful haemostasis
- Meticulous surgical closure to eliminate dead space
- Local analgesia/nerve block post-operatively
Identify the sites for amputation in the forelimb of small animals
- Forequarter amp: removal of scapula as well as limb
- Mid humerus
- Proximal third of humerus
Identify the sites for amputation in the hindlimb of small animals
- Proximal third of femur
- Disarticulation at hip
- Hemipelvectomy
Outline the key principles of digit amputation in small animals
- Major weight bearing on digits 3 and 4
- Careful dressing post-op required
Compare hindlimb and forelimb amputation
Cope better with HL as there is more even weight distribution
Compare the outcome for amputation and limb sparing procedures for the treatment of neoplasia
- Similar median survival rates if adjuvant chemotherapy given
- Some dogs may not cope with amputation e.g. large dog with FL amputation
Identify limb sparing procedures that may be used for neoplasia
- Resection of bone with appropriate margins
- Cortical allograft to maintain limb length
- Arthrodesis if near joint
- Chemotherapy
Identify the drugs commonly used in the treatment of osteoarthritis in dogs
- NSAIDs e.g. meloxicam, carprofen, galliprant/grapiprant
- Neutraceuticals e.g. chondroitin sulphate, glucosamine, EFAs
