Small animal MSK diseases 5 Flashcards
What results would be expected on serum biochemistry in a case of extraocular myositis?
CK usually normal
Outline the expected findings on orbital sonography/MRI in a case of extraocular myositis
- Swollen extraocular muscles
- Used to eliminate retrobulbar abscess as a differential
Outline the findings on biopsy of affected muscle in a case of extraocular myositis
Lymphocytic inflammatory infiltrate, gives definitive diagnosis
Outline the treatment of extraocular myositis
- Oral pred 1-2mg/kg SID (generally gives rapid and complete recovery)
- Continue treatment for 4-6 weeks minimum
- If relapse during tapering, add imuran or cyclosporin
Discuss the prognosis for extraocular myositis
Good prognosis for permanent recovery with proper therapy
List common diseases of the canine shoulder joint
- Soft tissue injuries
- Biceps tendon injuries e.g. biceps tendonitis
- Osteochondrosis
- Infraspinatous contracture
- Fracture of scapula or proximal humerus
- Osteoarthritis
List soft tissues that may be damaged in the shoulder joint
- Medial and lateral glenohumeral ligament (collateral ligaments)
- Subscapularis tendon
- Muscles adhering to joint capsule e. g. infraspinatous
Outline the clinical signs of soft tissue injuries of the shoulder in dogs
- Usually medium-large breeds
- May lead to instability
- Increased abduction angles
- Cranial drawer may be present
What abduction angle indicates medial glenohumeral ligament damage?
> 45degrees
Outline the diagnosis of soft tissue injuries of the shoulder in dogs
- Difficult
- Arthroscopy possible, allows assessment of all structures within joint capsule
- Assessment of abduction angles and cranial drawer under GA
List the treatment options for soft tissue injuries of the shoulder in dogs
- No treatment found to be long lasting
- Conservative: months
- Surgical imbrication or reinforcement possible (debated)
- Diathermy of medial aspect of joint capsule
- Rest and NSAIDs as required, gradual reintroduction of exercise as well as physio/hydrotherapy
Outline the diagnosis of biceps tendon injury in small animals
- Biceps test: pain on shoulder flexion with elbow extension
- During flexion, place fingers on medial aspect of greater tubercle to identify pain
- With complete rupture are able to extend elbow and shoulder to greater extent than normal due to lack of support from tendon
- Arthroscopy allows identification easily
Where is biceps tendon injury normal located in small animals?
Usually partial tear at insertion on supraglenoid tubercle of capsule
Outline the treatment options for biceps tendon injury in small animals
- Conservative: prolonged rest + NSAIDs
- Intra-articular corticosteroid injection
- Surgical release of biceps tendon at insertion if badly torn +/- re-attachment to proximal humerus with screw and spiked washer (tenodesis)
Describe the typical signalment for osteochondrosis in dogs
- Young (6-10mo)
- Medium to large breed dogs
- Esp. border collies
Describe the clinical signs of osteochondrosis in dogs
Clear pain on shoulder manipulation, esp. flexion
What site is predisposed to osteochondrosis in dogs?
Caudal humeral head articulating surface
Outline the diagnosis of osteochondrosis in dogs
- Radiography: subchondral lucency (caudal aspect of glenoid tuberosity may appear flattened)
- Arthrogram: highlights flap, may indicate cartilage damage
- Arthroscopy: direct visualisation of flap
Outline the treatment options for osteochondrosis in dogs
- Surgical removal of flap (arthrotomy or arthroscopy, break into pieces and remove)
- Conservative if not very lame
- Gentle exercise to gradually remove flap naturally (but can form joint mass, but rarely causes problem and comes sound)
Discuss the prognosis for osteochondrosis in dogs
- Good to excellent
- Esp. if <12mo
- Elbows and stifles poor
- Hocks very bad
- Shoulder generally good prognosis
Describe the clinical signs of mineralisation of forelimb muscles in small animals
- May be incidental finding
- May be associated with FL lameness and pain on firm palpation of region
- Commonly in supraspinatus and infraspinatus (bicipital groove)
Outline the treatment options for muscle mineralisation in the FL of small animals
- Conservative management (rest)
- Surgical excision possible (controversial)
Describe the typical signs of infraspinatus contracture in a dog
- Flexed elbow with external rotation of limb
- Working dogs, repetitive trauma
Outline the treatment of infraspinatus contracture in dogs
- Surgical sectioning of the tendon
- Leads to instant improvement, good long term prognosis
List the common diseases of the elbow joint in dogs
- Elbow dysplasia
- Osteoarthritis
- Elbow fractures
What are the main underlying disorders in elbow dysplasia in dogs?
- Fragmented medial coronoid process
- Osteochondrosis dissecans
- Ununited anconeal process
- Fragmented medial epicondyle
- Tendon enthesiopathy (bony exostosis in tendon)
Describe the characteristic appearance of elbow dysplasia
- Abducted FLs
- Externally rotated
- Do not take full pressure on limb
List the factors that contribute to the development of elbow dysplasia
- Genetic make up
- Growth rate
- Diet (high calcium)
- Exercise
Outline the possible treatment for elbow incongruity resulting from a short ulna, that may lead to elbow dysplasia
- Short ulna leads to anconeus coming up against caudal aspect of humeral condyles, leading to abnormal pressure on joint
- Cut ulna (ulnar osteotomy) to bring into alignment and reduce incongruity
- Several months required to heal
Which individuals are predisposed to fragmentation of the medial coronoid process?
- Large breeds e.g. Rotties, Bernese mountain dog, Newfoundland, Staffies, retrievers
- Males > females
Describe the clinical signs of FMCP in dogs
- Signs usually 4-7mo
- variable FL lameness, worse after rest, pain on rotation of antebrachium
- Elbow flexion and rotation of antebrachium
- Elbow joint effusion caudally, on trochlear ridge, adjacent to ulna
- Outward rotation and abduction when standing
Describe the pathology seen with FMCP in dogs
- Fissure/fragmentation of craniolateral part of MCP
- Single fragment with attachments to annular ligament usually
- +/- thickened cartilage, gross step between cranial border of articular surface of ulna and radius, eburnation resulting in “kissing lesion” on opposing humeral articular surface
Discuss the treatment options for FMCP in dogs
- Conservative and surgical possible, but DJD progresses with both
- Most treated conservatively initially, surgical if insufficient (rest, NSAIDs, neutraceuticals)
- Surgical: arthrotomy/scopy to remove fragment, or proximal ulnar osteotomy to remove abnormal stresses on coronoid, or sliding humeral osteotomy to reduce pressure on fragmented coronoid and allow healing
Which breeds are predisposed to OCD underlying elbow dysplasia?
Newfoundlands and retrievers
Outline the clinical signs of osteochondrosis dissecans underlying elbow dysplasia
- Onset 4-7mo
- Same as for FMCP
- Bilateral in 50-90% of cases
Discuss the aetiology of OCD underlying elbow dysplasia
- Cause unsure
- Increased incidence with increased energy intake (+/- increased Ca/P)
- Growth rate
- Birthweight
Discuss the management of OCD underlying elbow dysplasia
- Conservative: rest, analgesia, neutraceuticals, balanced diet
- Surgical: removal of flap, debride subchondral bone, blood and mesenchymal stem cell precursors encourage healing by fibrocartilage
Which breeds are predisposed to an ununited anconeal process?
GSD and Bassett Hounds
Describe the clinical signs of ununited anconeal process
- Onset 4-12mo
- Lameness, pain on elbow manipulation, crepitus
- Joint effusion
- Bilateral lameness in 11-47% of cases
Briefly outline the pathophysiology of an ununited anconeal process
- Anconeal process is secondary centre of ossification, usually fuses by 120days
- Failure to fuse after 20 weeks is abnormal, AP remains detached
- Distal aspect of anconeus comes up against caudal aspect of humerus, leads to repeated trauma, no fusion, leads to breakage
Discuss the treatment for an ununited anconeal process
- Conservative has poor prognosis
- Surgical: removal (variable results, short term improvement, long term instability and DJD), re-attachment with lag screw and K-wire (NB poor reduction = incongruity, implant failure), ulnar osteotomy (good/excellent function in most cases), ulnar osteotomy and re-attachment (excellent outcome at 18mo with only mild increase in DJD)
Which breeds are predisposed to humeral intercondylar fissue
Spaniels mainly (springer, cocker, cavvie), also Labs
Outline the clinical signs of humeral intercondylar fissure
- Chronic, low grade, intermittent lameness
- May be acute, severe lameness if condyle fractures
- Pain on elbow manipulation and pressure on condyle
- Squeezing of condyles painful as close the fissure between the condyles
Describe the diagnosis of humeral intercondylar fissure
- Difficult to see on radiograph unless radiograph parallel to fissure, may see other changes e.g. extra bone proximal to condyle
- CT imaging better
- Must radiograph contralateral limb if identify condylar fracture in spaniels
Outline the treatment options for humeral intercondylar fracture
- Conservative: risk of fracture of condyle as a result of minimal trauma, poor choice
- Surgical: prophylactic transcondylar lag screw
List the different types of elbow fracture that may occur in dogs
- Supracondylar
- Unicondylar
- Bicondylar
What is meant by a supratrochlear fracture? What is the consequence of this?
- Fracture through supratrochlear foramen
- epicondyles symmetrical, but gross instability in supracondylar area
Where do unicondylar fractures typically occur in dogs?
- Intra-articular
- Usually lateral condyle
Outline the treatment of unicondylar fractures in young and older animals
- Young: screw and k-wire
- Older: lag screw and plate on supratrochlear ridge
Discuss the prognosis for unicondylar, supracondylar and intercondylar fractures in dogs
- Favourable prognosis for uni and supracondylar fractures, 65-70% regain reasonable function
- Intercondylar will not heal, requires support throughout life
Explain what is mean by bicondylar fractures in dogs
- Intercondylar articular fracture with supracondylar fracture
- Can be transverse (T shaped) or oblique (Y shaped) supracondylar fracture lines
Discuss the management of bicondylar fractures in dogs
- Very challenging need to refer
- Marked swelling and instability leads to collapse
- Require a lot of implants
- Guarded prognosis
- Strict post op exercise restriction, but maintain ROM with passive physio and hydro
List the common disorders of the antebrachium in small animals
- Angular limb deformities
- Fractures
- Ligament injuries (mostly carpal joint)
Describe the common presentation of metacarpal fractures in small animals
- Fracture all bones usually
- Usually hx of heavy object falling on foot, trapping and twisting foot in hole
Discuss the management of metacarpal fractures in small animals
- If one or more metacarpal bones in tact, can place cast or bandage
- If all 4 affected, need fixation: ESF, small plates and screws, IM pins and wires
- Alignment not as important as other areas, but severe lack of alignment leads to valgus deformity and banana shape in caudocranial plane
List common primary appendicular neoplasias
- Osteosarcomas (proximal humerus, distal radius)
- Fibrosarcoma, haemangiosarcoma, chondrosarcoma
- Synovial cell sarcoma
Describe the typical signs of appendicular neoplasia
- Progressive lameness despite analgesia
- Progressive muscle atrophy
- Characteristic radiographic changes
Compare the occurrence of primary and secondary appendicular neoplasias
Primary more common than secondary (metastatic) neoplasia
Outline the treatment of appendicular neoplasia in small animals
- Amputation/limb sparing + chemo e.g. carboplatin
- Radiation
- Palliation (short term, analgesia)
- All treatment is palliative, PTS once QOL inadequate
Describe the clinical signs of a nerve root tumour in dogs and cats
- Chronic lameness (very severe)
- Marked muscle atrophy
- Older animals
- +/- axillary mass
- Neurological deficits
Discuss the management of nerve root tumours in dogs and cats
- Poor prognosis
- Poor response to analgesia
- PTS
List the forelimb diseases common in cats
- Elbow: osteoarthritis and synovial cysts
- Pad/digital injuries
- Fractures
- Cat bites
- Air gun pellet injuries (but often incidental finding)
Which radiographic view is most useful to diagnose a UAP?
Flexed lateral elbow
Which radiographic view is most useful to diagnose OCD of the elbow?
Craniocaudal elbow
What would be expected on synovial fluid analysis in elbow dysplasia?
Normal or degenerative
Outline the typical presentation for hyperextension injuries of the carpus in dogs
- Large, active dogs
- Hx of jump/fall from height
- Soft tissue swelling
- Uncomfortable on manipulation
- Crepitus
- Altered ROM in flexion and extension
Which radiographic views are most useful for hyperextension injuries of the carpus in dogs, and what findings would be expected?
- Dorsopalmar and mediolateral views of both carpi
- Mediolateral exposure with manus stressed to maximal carpal extension
- Joint angle exceeds 15-20degrees during stress radiograph
Outline the treatment options for hyperextension injuries of the carpus in dogs
- Conservative almost invariably unsuccessful
- Arthrodesis recommended (partial or pancarpal)
Which radiographic views are most useful for the diagnosis of collateral ligament injuries of the carpus in dogs, and what findings would be expected?
- Mediolateral and craniocaudal views, stressed views
- Enthesophytes may be seen at sites of ligamentous insertion
Outline the treatment options for collateral ligament injuries of the carpus in dogs
- Grade 1 or 2: external support 6-8 weeks, plus physio, NSAIDs, cryotherapy
- Grade 3: surgery required, primary repair of torn ligament, placement of prosthetic ligament (suture), partial/complete arthrodesis
List common hip disease of small animals
- Hip dysplasia
- Perthes disease
- Osteoarthritis
- Luxation
- Fractures of proximal femur or pelvis
- Muscle strains - uncommon (e.g. iliopsoas)
Explain the pathogenesis of canine hip dysplasia
- Macroscopically normal hips at birth, but changes begin within a few weeks
- Rapid growth and abundant food promote expression of HD
- Initially joint laxity due to incongruency of femoral head and acetabulum
- increased joit effusion pushign femoral head out of acetabulum
- Exacerbates subluxation
- Microfractures occur esp. of dorsal acetabular rip
- Damage to cartilage occurs
- Fibrosis and incraeased gluteal muscle vol stabilises joint, animal comes sound
- Later leads to DJD later in life
What test can be performed in order to assess hip in a case of suspected hip dysplasia?
Ortolani test
Describe the ortolani test
- Used to assess hip laxity by assessing the angle of subluxation and angle of reduction
- Performed under sedation/GA
- Lateral or dorsal recumbency
- Press down on femur to assess degree of subluxation
- Then abduct the hip until pops back into acetabulum to give the angle of reduction
Which radiographic views should be taken to assess hip dysplasia?
- VD extended femur view
- Lateral pelvis/LS junction, +/- flexed view
- Frog leg view (NB this makes degree of subluxation look less significant)
Discuss the treatment options for hip dysplasia in dogs and cats
- Conservative management is mainstay
- Surgery possible (but difficult to recommend as will improve without these
- Immature dog: pectineus myotomy/myectomy, triple/double pelvic osteotomy, femoral head and neck excision, pubic symphysis possible
- Mature dog: femoral head and neck excision, total hip replacement (both also cat)
Explain how a pubic symphysis surgery can be used to treat hip dysplasia
- Very young animals only
- Damage pubic symphysis to form a fixed point, so pelvis rotates and captures femoral head
- Must be 12-16wo
Outline the conservative approach to hip dysplasia management
- Weight control
- Regular exercise to build muscle for joint stabilisation
- Physio and hydrotherapy
- Strategic analgesia
- +/- neutraceutical
List the criteria that would make an individual a candidate for triple pelvic osteotomy
- Painful hips
- Non-responsive to analgesia
- Unstable but reducible hips
- No/minimal remodelling or degenerative changes (indicated by clean clunk with ortolani test)
- Mainly immature dogs 5-10mo
Briefly outline the procedure for a triple pelvic osteotomy
- Cut ilium, ischium and pubis
- Acetabular segment rotated laterally to capture femoral head, stabilise hip and lead to clinical improvement and reduced DJD
- Stabilise segment with plates based on degree of rotation as determined from Ortolani test
Describe the typical radiographic appearance of Perthes disease
- Mottled radiolucency of femoral head and neck
- Femoral head collapses into triangular shape
List the treatment options for Perthes disease
- Conservative management (rest, NSAIDs)
- Femoral head and neck excision
- Total hip replacement
List common diseases of the stifle in small animals
- Cranial cruciate ligament rupture (caudal possible but very uncommon)
- Meniscal damage
- Collateral/multiple ligament rupture
- OCD
- Patellar luxation
- Fracture of femur, tibia, patella
Describe the typical signs seen with cranial cruciate ligament disease in small animals
- Avoidance of stifle flexion when sitting
- Stiff to rise
- Increased weight bearing on contralateral limb
- Shift weight onto FLs
- Hip hike on affected side
- Circumduction of leg rather than flexing stifle
- Shortened anterior (moving forward) phase of swing
- May be muscle atrophy of affected legs, esp. quads
- Stifle effusion possible (unclear edges of patella)
- Medial buttress may be palpable
- Pain on extension of limb
What tests should be performed in a case of suspected cranial cruciate ligament disease in dogs?
- Cranial drawer (sedate or GA only, painful even in normal)
- Cranial tibial thrust (possible in conscious)
What are the 2 main aetiologies of cranial cruciate ligament disease in dogs?
- Acute trauma
- Degenerate ligament (more common)
In what planes are he the bands of the cranial cruciate ligament taut and how does this relate to the cranial drawer test?
- Small craniomedial: taut in flexion and extension
- Large caudolateral band: taut only in extension
- Most partial tears involve smaller CMB, drawer only present in flexion
Describe the use of radiography in the diagnosis of cranial cruciate ligament disease in dogs
- Indicates disease in joint, rather than identifying underlying pathology in these cases
- Joint effusion visible
List the treatment options for cranial cruciate ligament disease in dogs
- Conservative management
- Arthrotomy or arthroscopy
- Surgical: intra-extra articular or combined methods (e.g. extra-capsular suture), plateau levelling methods (CWO, TTA, TPLO_
Outline the conservative management of cranial cruciate ligament disease
- Analgesia, exercise modification, physio
- Reasonable outcome for dogs <17kg
- Poor recovery if meniscal damage present
- Degenerate conditions persist e.g. concurrent meniscal injury
- Rupture in other stifle within 2 years common
Outline the use of intra-extra articular or combined surgical treatments for cranial cruciate ligament disease
- Stability from prosthesis/tissue
- Some loss of joint ROM
- E.g. over-the-top technique (graft), tight-rope, extra-capsular suture (thread through and attach to condyle to act as ligament)
- Often break as difficult to mimic correct insertion and origin of ligament
Outline the use of plateau-levelling methods for the surgical treatment of cranial cruciate ligament disease
- Eliminate tibiofemoral shear force
- Stability only during weight bearing, cranial drawer still present when non-weight bearing
- Preserves joint ROM
- E.g. cranial Tibial closing wedge osteotomy (CWO), tibial plateau levelling osteotomy (TPLO), tibial tuberosity advancement (TTA)
Compare the advantages/disadvantages of the different surgical approaches to cranial cruciate ligament disease
- Better quicker after TPLO or TTA
- Some advantages with TPLO evidenced
- Extra-articular has lower complication rates (then TPLO, then TTA), but poorer success
- Larger dogs and terriers benefit from invasive procedures
Describe the typical presentation of meniscal injury
- May be more painful/lame +/- audible click
- Present at time of CrCL rupture (partial 5-25%, complete up to 80%)
- Delayed meniscla injury up to 14%
- Usually caudal horn of medial meniscus
- Caudal longitudinal tear (bucket handle) and crushing of caudal horn most common
Briefly outline the treatment of meniscal injury with CrCL rupture
- Inner 2/3rds of meniscus avascular so healing is poor, consider partial meniscectomy
- With TPLO, meniscus removed
Describe the aetiologies of canine patellar luxation
- Quad/extensor muscle malalignment
- Shallow patellar groove due to patella not being present in groove during development
- Bony deformities of femur and tibia
- Usually congenital, occasionally traumatic
Which breeds are predisposed to canine patellar luxation?
- Terriers
- Large dogs (labs, mastiffs)
Describe the clinical presentation of canine patellar luxation
- Intermittent hopping lameness for a few steps, then normal
- May be crepitus on manipulation
- Medial patellar luxation most common (congenital)
- Lateral luxation seen in large breeds or following trauma
- Occasionally concurrent cruciate ligament rupture
Describe grade 1 canine patellar luxation
- Patella usually in trochlea
- Can be luxated, but immediately returns to trochlea
Describe grade 2 canine patellar luxation
- Patella usually in trochlea
- Can be luxated, tend to remain luxated unless replaced or stifle extended
