Small animal MSK disease Flashcards
Examination of lame animals, joint disease
Which breed of dog is predisposed to elbow dysplasia?
Labrador retriever
Which breed of dog is predisposed to cruciate disease?
West Highland White terrier
What conditions are more likely where there is chronic and progressive onset of lameness?
- Osteoarthritis
- Degenerative cruciate disease
What conditions are more likely with acute onset of lameness?
- Trauma
- Infection
- Foreign body
What conditions may present with acute worsening of a chronic lameness?
- Cruciate rupture on patellar subluxation
- Pathological fracture resulting from bone neoplasia
Outline the importance of activity in the history for a lameness examination of cat or dog
- Exercise tolerance and general activity important in cat, rarely show true lameness
- Ability to jump in cats
- Reluctance to negotiate stairs may indicate HL problem
Describe the common clinical course for panosteitis
Waxing and waning, shifting between different bones affected
Describe the common clinical course of a cruciate rupture
Acute lameness followed by slow improvement
Describe the common clinical course for patellar subluxation or superficial digital flexor tendon instability
Acute and intermittent signs, lame when slips out of position then sound when back into position
Describe the typical clinical presentation of foot pathology
Worse on harder surfaces
List the aspects of the examination of a small animal presented with lameness
- Observation in consulting room
- Dogs walked outside
- Full clinical examination
- Lameness examination
- Neurological examination
Describe the appearance of paws in a fully weight bearing vs not fully weight bearing
- Fully: paw spread
- Not fully weight bearing: paw slightly clenched
What may cause an inability to fix the stifle and how will this present clinically?
- Damage to quads due to patellar fracture,
rupture of patellar tendon, femoral nerve injury - Stifle will drop as put weight on limb
- Stifle will flex
Describe a head nod in the assessment of lameness in the dog
Head nod on unaffected limb when walked as take more weight on normal leg, only used for forelimb
Describe the hip movement assessment in the identification of lameness in the dog
Used for hindlimbs, hip will rise higher and quicker on affected leg
What may indicate subtle neurological deficits when walking a dog for the assessment of lameness?
- Catching nails (may hear this)
- turning in tight circles exaggerates the deficits
What may be indicated by respiratory deficits in a lameness work up in small animals?
- Pulmonary osteopathy
- Metastatic disease from osteosarcoma
What may be indicated by urinary tract disease for a lameness work up in small animals?
- Association with lumbosacral discospondylitis and resulting lameness
- May be extension of urinary disease or prostatic disease
Explain the examination for prostatic disease in a lameness work up and describe how this may present in small animals
- E.g. prostatic carcinoma that may have metastatic spread to long bones
- May also have strang/dysuria, haematuria
Describe the appearance of neurogenic muscular atrophy
- Marked, very rapid
- Follows pattern of innervation i.e. sciatic affects biceps femoris
Describe the examination of the feet and pads in a lameness work up in small animals
- Palpate digits and pads individually
- Twist each nail - blood or pain on twisting indicates nail injury
- Any wear to nails may indicates dragging and in HL may suggest CDRM in GSD, lumbosacral disease, IVDD
- Examine nail beds - common site of pulmonary adenocarcinoma metastasis in cats
Describe the examination of joints in a lameness work up in small animals
- Plapate for effusions (esp. stifle)
- Pain
- Medial buttress to stifle indicates problem
- Unsharp margins on patellar tendon indicates effusion
- Instability e.g. in the cruciate using specific tests e.g. cranial drawer
- Abnormal movement e.g. intertarsal subluxatoin, carpal hyperextension shown by palmar/plantar stance
Describe the examination of ligaments and tendons in a lameness work up in small animals
- Palpate for swelling
- Heat
- Pain
- Resulting instability if ruptured e.g. patellar higher than expected
- May be unstable in their grooves
Outline the assessment of patellar instability in a lameness work up in small animals
- May subluxate medially or laterally
- Often need to flex and extend stifle joint with pressure on patella to bring about subluxation
What tests are used to assess for cruciate rupture in small animals?
- Cranial drawer
- Tibial thrust
Describe the examination of bones in a lameness work up in small animals
- Palpate as well as radiograph
- Squeeze: in panosteitis will resent this
- Pain on gentle palpation may indicate neoplasia
- Perform towards end of ecamination
Describe the neurological aspects assessed in the lameness work up of a small animal
- Neck or thoracolumbar pain assessment
- Palpate axillary region for mass e.g. nerve root tumour
- Rectal examination if HL neurological deficits seen (palpate abnormalities in sacrum or rectal canal(
- Check anal and rectal tone
Outline the use of radiography in the lameness work up of a small animal
- Mainstay of further investigation
- Good quality orthogonal views required
- Examine for primary and secondary disease
Outline the use of synoviocentesis in the lameness work up of a small animal
- Single joint if only this joint is swollen, suspicion of OA or septic arthritis
- Multiple if polyarthritis suspected (worth tapping 2/3)
- Examine in house with DiffQuik and send off
Outline the use of blood tests in the lameness work up of a small animal
- Rheumatoid Factor (RF) for rheumatoid arthritis
- ANA for SLE (may be indicated by leukopaenia, pain in muscles)
- Borrelia burgdorferi serology or PCR of joint fluid
Outline the use of CT in the lameness work up of small animals
- Useful for elbows as will clearly demonstrate FCP and humeral intercondylar fissure (common in Springers)
- Also to visualise mineralisation of infra and supraspinatus tendons
Outline the use or MRI in the lameness work up of small animals
- Better for soft tissues, good for stifles, shoulders and detection of foreign bodies
- Also good for spine to examine for nerve root tumours, lumbosacral disease etc.
Outline the use of ultrasound in the lameness work up of small animals
Used occasionally e.g. bicipital tendon, Achilles and flexor tendons
Outline the use of arthroscopy in the lameness work up of small animals
- Good for shoulder, elbow, stifle
- Difficult for carpus and talocrural joint
- Can be diagnostic and used to treat e.g. fragmented coronoid process
- Difficult, equipment expensive
What additional tests may be used in the lameness work up of small animals?
- Biopsy (any mass or swellings)
- Nerve conduction studies
- EMG
- Muscle biopsy (e.g. for Labrador Retriever myopathy)
How would you approach a case of a lame small animal where nothing is found on diagnostic testing?
- Treat with NSAIDs and rest and re-evaluate in 2 weeks, or 2 days if very lame
- Call owner midway through period of waiting for next appointment and enquire after pet
- Offer referral early
Describe the method for the cranial drawer test in small animals
- Lying or standing (lying easier), sedated/GA or conscious (sed/GA better)
- Index finger on patella, thumb on sesamoid behind stifle
- Left index finger on tibial crest, thumb on head of fibula
- Right hand holds stable, while apply pressure on fibula
- Perform in various degrees of flexion and extension
- If abnormal, tibia will move cranially
Describe the method for the tibial thrust test in small animals
- Easier if joint is painful
- Require practice and occasionally sedation or GA
- Hold femur with right hand, place index finger on patella
- Flex hock and tibia will move forward spontaneously
What conditions would the following history be indicative of?
Stiffness, particularly in the mornings, lameness worsens after exercise, and waxes and wanes, lame limb swaps between legs
- Osteoarthritis
- Hip dysplasia
- Immune mediated polyarthritis
- Septic arthritis
- Perthes disease if hips
Describe the signs you would expect to find on clinical examination of a dog with arthritis
- Lameness
- Pain on manipulation of joints
- Associated muscle atrophy
- No neurological deficits
- +/- systemic signs depending underlying cause
What is rheuamtoid arthritis?
Immune mediated erosive arthritis, leading to changes in subchondral bone
What is the difference between primary and degenerative arthritis?
- Primary has no underlying aetiology
- Degenerative is as a result of abnormal loading e.g. as a result of hip dysplasia
Following a provisional diagnosis of osteoarthritis, what is an appropriate approach?
Trial therapy of rest and analgesia (NSAIDs) for 1-2 weeks
List the tests used in order to form a definitive diagnosis of osteoarthritis
- Further manipulation fo joints under sedation or GA e.g. Ortolani sign
- Radiography
Ultrasound - EMG, CT, MRI, scintigraphy possible
- Arthrocentesis
- Arthroscopy
- Exploratory arthrotomy
- Intra-articular or regional blocks
Evaluate the use of intra-articular or regional blocks for the diagnosis of osteoarthritis
- Need sedation
- rarely performed in small animals
- Never quite show normal movement expected, so cannot tell how much abnormal movement is from sedation or due to joint pathology
What radiographic views are required for the diagnosis of osteoarthritis?
- Depends on joint affected
- Always require standard orthogonal views +/- stressed views
- Radiograph opposite side for comparison
What is the first sign that is likely to be seen on radiography that indicates joint disease?
Effusion, demonstrated by increased opactiy within the joint and smaller fat pad (lucent triangle)
Discuss the use of ultrasound in the diagnosis of osteoarthritis
- Good for peri-articular soft tissue structures, e.g. bicipital tendon
- Can be used for detection of meniscal tears
- Requires skilled operator
What is the most likely underlying aetiology if only one joint is arthritic?
Septic or traumatic
Outline the use of arthrocentesis in the diagnosis of arthritis
- Single or multiple tapped depending on presentation
- Collection in to plain, EDTA and blood culture medium if likely to be infected
- Smears for cytology as well as count from EDTA sample
What is the normal result for a mucin test of synovial fluid?
Add joint fluid to acetic acid, and forms tight clot
What is the demonstration of foamy macrophages in synovial fluid indicative of?
Degenerative disease
What would large numbers of neutrophils in synovial fluid be indicative of?
Sepsis and polyarthritis/autoimmune
Compare the colour of synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
- Normal: clear/pale yellow
- DJD: yellow
- Immune mediated arthritis: yellow (+/- blood tinged)
- Bacterial infective arthritis: yellow (+/- blood tinged_
Compare the clarity of synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
- Normal: transparent
- DJD: transparent
- IMPA: transparent or opaque
- Bacterial Infective arthritis: opaque
Compare the viscosity of synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
- Normal: very high
- DJD: high
- IMPA: low/ery low
- Bacterial: very low
Compare the mucing clot synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
- Normal: good
- DJD: good - fair
- IMPA: fair - poor
- Bacterial: poor
Compare the formation of spontaneous clots of synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
- Normal: no
- DJD: +/-
- IMPA: often
- Bacterial: often
Compare the protein content of synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
given in g/dL
- Normal: 2-2.5
- DJD: 2-3
- IMPA: 2.5-3
- Bacterial: >4
Compare the white cell content of synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
given in x10^9/L
- Normal: <2
- DJD: 2-5
- IMPA: 4-370
- Bacterial: 40-267
Compare the neutrophil content of synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
given as %
- Normal: <5%
- DJD: <10%
- IMPA: 10-95%
- Bacterial: >90%
Compare the mononuclear cell content of synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
given as %
- Normal: >95%
- DJD: >90%
- IMPA: 5-90%
- Bacterial: <10%
Compare the glucose content of synovial fluid found in normal joints, DJD, immune mediated arthritis, and bacterial infective arthritis
given as % of serum value
- Normal: >90
- DJD: N/A
- IMPA: N/A
- Bacterial: <50
Outline the use of advanced imaging in the diagnosis of arthritis
- CT and MRI
- May demonstrate bony changes, as well as underlying aetiology e..g elbowhip dysplasia
Outline the use of arthroscopy in the diagnosis of arthritis
- Reduced joint morbidity with this method
- Magnified image
- May be therapeutic as well as diagnostic depending on aetiology
Outline the use of arthrotomy in the diagnosis of arthritis
- Visualisation of joint
- Can take synovial biopsy is unsure of nature of arthritic/inflammatory change in joint
What is the major disadvantage of arthrotomy for the diagnosis of arthritis?
Increases morbidity of joint (but often performed anyway)
Outline the pathophysiology of osteoarthritis
- Fibrillation of articular cartilage of weigh bearing areas leads to fissuring and ulceration
- Microfracture leads to stiffening of subchondral bone and therefore abnormal loading
- Abnormal loading then leads to joint remodelling
What causes the pain associated with osteoarthritis?
Synovitis and exposure of the subchondral bone
Describe the radiographic signs seen with osteoarthritis
- Joint effusion
- Osteophyte formation and bone remodelling
- Enthesiophytes
- Subchondral sclerosis
- Subchondral cysts (more common on CT)
- Muscle atrophy
Describe the cycle of presentation of osteoarthritis in young animals
- Primary disease leads to pain/instability, OA initiated leading to pain, lameness and restriction of movement
- Muscular growth provides support and stabilises joint, limiting signs
- Periarticular fibrosis occurs to increase stability
- Initially painful, improves, then as ages arthritis will become more severe
In which joints is osteoarthritis more significant?
Small, tight joints e.g. tarsus or elbow, vs. large “padded” joints e.g. stifle or hip, and worse in high mothion joints e.g. antebrachiocarpal joint vs carpometacarpal
What are enthesiophytes?
Bony extensions into surrounding ligaments and tendons around a joint, are associated with severe arthritic change
What are the 3 key treatment objectives for osteoarthritis?
- Control pain
- Achieve acceptable level of exercise
- Limit progression of the disease
Outline the general points included in a treatment plan for osteoarthritis
- Weight control
- Exercise modification +/- physio/hydro
- Analgesia e.g. NSAIDs
- Nutraceuticals
- Salvage procedures in severe cases
Outline how flare ups of osteoarthritis may be managed
- Initial analgesia 7-10days of NSAIDs
- Rest, only 5min walks 3x/day on lead to maintain movement
- gradual reintroduction of exercise over 2-3 week period
- Physio/hydro to maintain muscle bulk and aid stability of joint
Outline the pharmaceutical management of osteoarthritis
- NSAIDs mainstay
- Corticosteroids for severe, non-responsive or end-stage cases
- Gradually taper doses
- May be life-long treatment, monitoring required
- May add nutraceuticals
Discuss the use of nutraceuticals in the management of osteoarthritis
- Evidence lacking
- 6 weeks before any beneficial effects
- Chondroitin sulphate and glucosamine
- Glucosamine has mild anti-iflamm as well as effect on chondrocyte metabolism
- Essential fatty acids may be beneficial
- Also turmeric and green-lip mussel
List some additional research developments that have been suggested for the treatment of osteoarthritis
- Micropicking
- Joint resurfacign
- Platelet rich plasma
- Stem cell therapy
- Gene therapy
Outline micropicking in the treatment of osteoarthritis
- Perforation of subchondral bone plate to allow cartilage to heal over it
- Unclear if beneficial
Outline joint resurfacing in the treatment of osteoarthritis
- Full thickness defects
- Fibrin plus and other biodegradabl scaffolds
- Replace fragmented coronoid process, or fragmented surface of humerus
- Specialist and expensive
Outline the use of platelet rich plasma in the treatment of osteoarthritis
- Variable results
- Take blood, concentrate platelets and re-inject back in to patient’s joint
Outline stem cell therapy in the treatment of osteoarthritis
Harvest adipocytes and remove stem cells, grow on and inject into joint
List the salvage procedures that may be used in the management of osteoarthritis
- Removal of articular surfaces
- Total joint replacement
- Fusion of joint (arthrodesis)
Outline the diagnosis of feline osteoarthritis
- More difficult to detect, very vague signs, less inflammation vs. dog
- Less jumping, depressed demeanour, reduced ability to groom
- Rarely see overt lameness, but may do esp. elbow
- Trial meloxicam and assess response
Discuss the features that predispose to ligament sprain and rupture
- Longitudinally orientated bundles of collagen fibre with greatest strength during tension
- Very inelastic - >10% elongation leads to permanent damage
- Cannot replace or repair ligaments
What is meant by first degree ligament sprains?
Few collagen fibres damaged, minimal functional change
Outline the prognosis and management of first degree ligament sprains
- Rest 7-10 days, NSAIDs, +/- support
- Leads to full recover in most cases, although there will be permanent damage, generally no lameness
What is meant by second degree ligament sprains?
Still grossly intact, but more fibres damaged, haematoma may form and some degree of functional deficit
Outline the management and prognosis for second degree ligament sprains
- Needs treatment to regain function
- If stable, conservative and support dressing
- Unstable: imbricate ligament, support dressing
- 6-10 weeks healing, 3-6 months to regain function
What is meant by third degree ligament sprains?
Interstitial disruption or avulsion, function completely lost, may not be regained
Outline the management and prognosis for third degree ligament sprains
- Needs treatment to regain function
- Suture repair or ligament replacement, possible tension banding
- 6-10 week healing, 3-6months to regain (partial) function
- Joint may require arthrodesis ultimately
What is a common cause of third degree ligament sprains and what structures are involved?
- Often shearing injury e.g. RTA
- Damage includes collateral ligaments and cartilage
Outline the generic conservative treatment of ligament sprains
- Rest, oftenmonths
- Reduce swelling using cold packs, massage and medication
- External coaptation e.g. Robert Jones bandage, bespoke hinged dressing
List the surgical options for management of ligament sprains
- Primary ligament repair if enough left
- Internal ligament splint/prosthetic replacement
- Immobilisation with transarticular ESF
- Arthrodesis
When is the use of transarticular ESFs indicated with ligament sprains?
Where the joint is grossly unstable
Which breeds of dog are predisposed to plantar ligament degeneration?
- Shetland sheep dog
- Collies
- Racing Greyhounds
Outline the common results of plantar ligament degeneration
- Degeneration leading to subsequent rupture of the ligaments
- Normally subluxation at level of proximal intertarsal joint
- Often bilateral
- In athletic dogs with traumatic rupture often also fracture of hock
What management is required for cases of plantar ligament degeneration and rupture in dogs?
Arthrodesis of affected joint, commonly calcaneoquartal arthrodesis (sublux of proximal intertarsal) using plates
Explain the typical pathophysiology of carpal ligament injuries
- Collateral ligament injuries to antebrachiocarpal joint usually extension injuries
- Naturally have a degree of valgus, therefore medial ligament rupture most serious and gives rise to valgus deformity
