SA Orthopaedics Flashcards
What should you check if there is a fracture on one side of the pelvis?
Check the other side for fractures as the pelvis is usually broken in 2 places
What would happen if you didn’t repair a hip fracture?
Osteoarthritis
How can you check whether a pelvic radiograph is straight?
Check that the obturator foramen are symmetrical
How do you know if an animal is deep-pain negative or positive?
Pinch foot
Animal will pull foot away on reflex, but if it is deep-pain positive it will also look around/yelp/HR will increase
What should you assess when an animal is presented with a possible pelvic fracture?
ABC
Control haemorrhage if present
Fluids and shock therapy
Check for other injuries eg diaphragmatic rupture, neurological injury, urinary tract, function of pelvic nerve-perineal reflex
Analgesics-opioids, NSAIDs (not if renal dysfunction)
How may a fractured pelvis affect breeding?
May lead to pelvic narrowing
What is neuropraxia?
Nerve injury
Has voluntary movement but can’t feel ends of feet
Will recover
Fractures affecting which parts of the pelvis are suitable for conservative management?
Those on non-weightbearing axes:
Pubis
Ischium
Wings of ilium
What conservative management would you prescribe to a patient with pelvic fractures?
Cage rest for 4-6 weeks
If non-ambulatory: frequent turning and soft bedding
Check bladder qid if not urinating consciously
Analgesia (opioids- full or partial agonists of buprenorphine, NSAIDs if not worried about kidneys)
Surgical treatment is required for which fractures of the pelvis?
Sacroiliac separations
Iliac shaft fractures
Acetabular fractures
Femoral head and neck excision is only recommended for dogs up to which weight?
15kg
How do cats’ vertebrae differ from dogs?
Cats’ are longer and thinner
How do sacroiliac fractures commonly occur?
RTA in cats
How will an animal present if it has a sacroiliac separation?
Non-ambulatory
+++ pain (esp if nerve root entrapment)
Marked displacement
What treatment is required for sacroiliac separation?
Surgery:
- Lag screw fixation (most commonly used; one long screw in sacral body)
- Transillial pin
How would you repair an iliac shaft fracture?
Most require internal fixation (plating)
Surgical approach involves ‘gluteal roll up’
How would you repair an acetabular fracture?
Internal fixation (plate) Small dogs/cats: femoral head and neck excision Surgical approach involves trochanteric osteotomy or gluteal tenotomy
Which nerve runs over the greater trochanter of the femur?
Sciatic
What post-operative care would you recommend for pelvic fractures?
Cage rest/restricted room rest for 4-8 weeks
Treat as with conservative management-short on-lead walks (5-10 mins) until re-radiograph
See at 3, 7-10 days then 4-8 weeks post-op for repeat radiographs
Analgesia, soft bedding
Physio?
How would you identify a pathological fracture on a radiograph?
Thin cortices
What may cause a pathological fracture in puppies and kittens?
Nutritional deficiencies
What may cause a pathological fracture in a rottweiler?
Osteosarcoma (FLs)
How many carpal bones are there?
7
What are the carpal bones supported by?
Ligaments
Palmar fibrocartilage
Give some clinical signs of problems with the carpus
- FL lameness (usually non weight-bearing)
- Abnormal stance: palmigrade
- Soft tissue swelling
- Joint effusion
- Pain/discomfort on manipulation
- Crepitus on range of motion
- Instability: lateromedial or craniocaudal
Which dog breeds are more prone to degenerative processes in the carpal ligaments/palmar fibrocartilage?
- Collies
- Shelties
How would you diagnose a carpal/tarsal/metacarpal/metatarsal/phalangeal injury?
- History: acute vs chronic, trauma?
- Orthopaedic examination
- Diagnostic tests: radiography (plain vs stress views), CT, MRI (rare), synovial fluid analysis (OA, inflammatory), scintigraphy (to localise lameness)
How does hyperextension of the carpus occur?
Usually traumatic
Caused by disruption of palmar ligaments and fibrocartilage
How would a dog present if it had hyperextension of the carpus?
Palmigrade stance
Initial swelling of joint which would reduce after a few days, no obvious signs of pain
Which joint is most likely to be affected by hyperextension of the carpus?
Carpometacarpal
How would you idenitfy hyperextension of the carpus on a radiograph?
Opening in carpal joint space -> ligaments/fibrocartilage has ruptured
How do you treat hyperextension of the carpus?
- Partial carpal arthrodesis (pin/plate fixation)
- Pancarpal arthrodesis (dorsal/palmar plate. external fixator)
Shearing injuries of the carpus are more common on which aspect of the limb?
Medial
How many tarsal bones are there?
7
Give some clinical signs of problems with the tarsus
- HL lameness (usually non weight-bearing)
- Abnormal stance: plantigrade
- Soft tissue swelling
- Joint effusion
- Pain/discomfort on manipulation
- Crepitus on range of motion
- Instability: lateromedial or craniocaudal
Which tendon inserts on the calcaneus?
Common calcanean tendon
Give some specific pathologies that affect the tarsal joint
- Luxations/subluxations
- Fractures
- Shearing injuries
- Hyperextension
- OCD
- Luxation of tendon of SDFT
- Common calcanean tendon pathologies
How can you repair tarsal luxations/subluxations?
- Ligament rupture reconstruction
- Ligament augmentation with prosthetic ligaments
- Reattach avulsed ligaments if possible
- Pantarsal arthrodesis
How would you repair a fracture to the calcaneus?
Lateral or plantar plate fixation
How would you repair an avulsion of the common calcanean tendon/proximal fracture of calcaneus?
Pins and tension band on calcaneus
How would you repair fractures of the tarsal bones?
- Reduction and stabilisation with pins/lag screws/plates
- If very small fragments: conservative vs removing fragments
- Arthrodesis: partial tarsal arthrodesis vs pantarsal arthrodesis
How would you diagnose luxation of the superficial digital flexor tendon?
How does it occur?
- Intermittent lameness
- Popping sensation on hock (tarsus) ROM
- Caused by rupture of the medial or lateral retinaculum
How would you treat luxation of the superficial digital flexor tendon?
- Debridement of fibrous tissuse and tendon reduction
- Suture tendon and ruptured retinaculum
- Remove/imbricate (overlap) stretched retinaculum
- Lateral splint support for 2-3 weeks
Which tendons make up the common calcaneal tendon?
- Gastrocnemius
- Common tendon of biceps femoris, semitendinosus and gracilis
- SDFT
How could you differentiate between partial and complete rupture/avulsion of the common calcaneal tendon?
Partial: plantigrade stance with flexed digits (as SDFT is not affected)
Complete: plantigrade stance with normal/extended digits
How would you diagnose common calcaneal tendon injuries?
- History/orthopaedic exam
- Radiography: soft tissue swelling, chronic changes, avulsions
- US
- CT
How would you treat a common calcaneal tendon injury?
- Debride necrotic edges of tendon
- Suture tendon individually
- Make bone tunnels if avulsions of small bone fragments (to place sutures through)
- Reattach large avulsions: pins and tension bands
How would you manage a common calcaneal tendon injury post-surgery?
Immbolisation for 8-10 weeks:
- Cast/lateral splint (don’t provide much support)
- Calcaneotibial screw
- External fixator
Osteochondritis dissecans (OCD) is more common in which kind of dog breeds?
Large breeds
Osteochondritis dissecans typically affects which ridges of the talus?
Affects both, but medial more often
What is osteochondritis dissecans?
Disturbance of endochondral ossification
How would you diagnose osteochondritis dissecans?
- History/ortho exam
- Radiography
- CT
How do you treat osteochondritis dissecans?
- Conservative vs surgical (open or arthroscopy)
- Surgical has bette prognosis, but better results if patient <6 months old
What is likely to occur as a result of osteochondritis dissecans?
Long-term osteoarthritis
What is the prognosis for osteochondritis dissecans?
Poor
How would you treat a fracture/luxation of the central tarsal bone?
- Positional screw into 4th tarsal bone
- Lateral splint support for 4 weeks
Which dog breed is predisposed to tarsal hyperextension?
Shetland sheepdog
How would you treat subluxation/luxation of the tarsal bones?
Partial tarsal arthrodesis (bone plate or external fixator)
What are the principles of arthrodesis?
- Remove articular cartilage, exposing subchondral bone
- Maintain proper joint angles
- Rigid long-standing fixation (most commonly bone plates)
- Bone grafting
- Additional stabilisation: splints
What is the proper joint angle of the carpus?
10-12 degrees of extension
What is the proper joint angle of the tarsus in dogs and cats?
Dogs: 135-145 degrees of extension
Cats: 115-125 degrees of extension
Give some clinical signs of metacarpus/tarsus/phalanges injuries
- FL/HL lameness
- Soft tissue swelling
- Joint effusion
- Pain/discomfort on manipulation
- Crepitus on ROM
- Instability: lateromedial or craniocaudal
How would you treat metacarpal/metatarsal fractures?
Conservative with external coaptation (casts/bandages)
Surgical with IM pins or dorsal plates if:
->2 bones involved (esp bones II and III)
->50% displaced
-Base of bones are affected or aricular fractures
-Large breeds/working dogs
How would you repair luxations/subluxations of the phalanges?
- Reductions and primary repair of ruptured ligaments (support with external coaptation or external fixator)
- Toe amputation
Give some indications for imaging the skeletal system
- Acute/chronic lamess
- Skeletal/joint pain
- Fracture confirmation/characterisation
- Swelling centered on bones/joints
- Monitoring/screening for inherited musculoskeletal disease (eg hip dysplasia)
- Metabolic bone disease
- Evaluation of systemic disease
How may geometric distortion occur when taking a radiograph?
If structure is towards the edge of the collimated area, or not truly parallel to the film/detector
Give some limitations of radiography
- Oblique projections can create apparent artefactual lesions
- Poor soft tissue contrast resolution
What is serial radiography?
Multiple radiographs taken over a period of time
Why may you want to utilise serial radiography?
- Monitor progression of disease
- Assess dynamic component of disease
- Can be useful if diagnosis is uncertain
- Show diseases radiographically occult (hard to see) in their early stages
How should you describe a radiographic lesion using the Rontgen signs?
- Number of lesions
- Size
- Shape (inc margins)
- Location
- Opacity
What should you consider when you see a lesion on a radiograph?
- Could be an artefact of poor positioning/technique
- Could be a feature/variant of normal anatomy
- Could be a composite shadow of superimposed normal structures
What should you assess when looking at bones on a radiograph?
- Alignment, shape, length
- Periosteal reaction/cortical lysis/defects
- Endosteal/medullary changes
- Physes
What should you assess when looking at joints on a radiograph?
- Swelling/effusion
- Subchondral bone
- Periarticular changes
Why may you see a focal reduction in size of soft tissues (eg muscles) on a radiograph?
- Chronic lameness
- Neurogenic (eg nerve damage)
- Fibrosis/scarring
Why may you see a focal increase in size of soft tissues (eg muscles) on a radiograph?
- Trauma
- Abscess/seroma
- Granuloma
- Neoplasia
Why may you see a diffuse increase in size of soft tissues (eg muscles) on a radiograph?
- Oedema
- Cellulitis/vasculitis
- Diffuse neoplasia
What part of the bone is the endosteum?
Layer surrounding the medulla
A reduction in opacity means the radiograph is different how?
More black
Why may there be a reduction in opacity on a radiograph?
- May be artefactual
- If generalised: nutritional secondary hyperparathyroidism
- If focal: neoplasia, occasionally osteomyelitis
What % of mineral loss of a bone is required for it to have reduced opacity on a radiograph?
30-60%
Takes a minimum of 7 days to become apparent
What are the 3 descriptions of focal bone lysis?
How aggressive are they?
Geographic (less aggressive, area of lysis is fairly well-defined)
Moth-eaten
Permeative (more aggressive, lots of tiny areas of destruction, poorly defined)
Describe a typical aggressive bone lesion as seen on a radiograph
- Long transition zone
- Active periosteal reaction
- Cortical integrity is damaged by destruction/expansion
- Soft tissue swelling/mass
How should skeletal lesions be categorised?
- Monostotic/polyostotic
- Focal/generalised
- Symmetrical/assymetrical
What should you assess regarding joints on a radiograph of a lame animal?
- Soft tissue swelling
- Joint space width
- Subchondral bone opacity
- Osteophytes/enthesophytes
- Periarticular mineralisation
What are enthesophytes?
Abnormal bony projections as the attachment of a tendon/ligament
What are osteophytes?
Abnormal bony projections in joint spaces
Give some examples of subchondral defects
- Osteochondrosis
- Aseptic necrosis (femoral head)
- Septic arthritis
- Erosive arthritis (carpus/tarsus)
- Soft tissue neoplasia
- Trauma (avulsions)
- Osseous cyst-like lesions
- Osteoarthritis (only if very severe)
Give some pathologies that may occur on the periarticular bone of a joint
- Osteophytes (joint capsule)/enthesophytes (ligament attachments)
- Synovial osteochondroma (cats)
What is an osteochondroma?
Benign bone tumour
Appears as cartilage-capped bony projections on the surface of bones
How would you identify osteoarthritis on a radiograph?
- Soft tissue swelling/effusion
- Periarticular new bone at predictable sites (osteophytes) (eg end of patellar, trochlear ridge)
- Subchondral sclerosis
- Narrowed joint space (if weight-bearing/very severe)
- Look for primary disease process
With osteoarthritis, which part of the elbow is the first to get osteophyte formation?
Anconeal process
What is the significance of calcified bodies in the joints on radiographs?
- Common
- Normal at predictable sites (sesamoids, accessory centres of ossification)
What are the predilection sites of osteochondrosis?
- Caudal aspect of humeral head
- Media part of humeral condyle
- Lateral femoral condyle
- Medial trochlear ridge of talus
What are the predilection sites of osteosarcoma?
- Proximal humerus
- Distal radius/ulna
- Distal femur
- Proximal tibia
US is useful for which joint in particular?
Shoulder (soft tissue problems are common and difficult to evaluate with radiographs)
Which key soft tissue structures of the shoulder are useful to evaulate with US?
- Biceps tendon and sheath (craniomedial)
- Supraspinatus and infraspinatus muscles/tendons (lateral/craniolateral)
How is the hip joint kept stable?
- Teres ligament (attaches femoral head to acetabular fossa)
- Trans-acetabular ligament (ventral aspect of joint)
- Joint capsule
- Surrounding muscles
Give some developmental conditions of the hip joint
- Hip dysplasia
- Legg-Perthe’s disease
Give some acquired conditions of the hip joint
- OA
- Neoplasia
- Immune-mediated arthropathy
- VWHOOD (von Willebrand associated heterotopic osteochondrofibrosis of Dobermans)
Give some traumatic conditions of the hip joint
- Acetabular fractures
- Fractures of femoral head and neck
- Coxofemoral luxation
How would you characterise hip dysplasia?
Laxity and instability of the coxofemoral joint
Which animals are more prone to hip dysplasia?
- Large breed dogs
- Pedigree cats eg Maine Coon, Devon Rex
Which factors control the degree of joint laxity in hip dysplasia?
-Genetics, growth rate, nutrition, exercise
Give the aetiopathogenesis of hip dysplasia
- Laxity due to poor soft tissue support of coxofemoral joint -> thickening of joint capsule -> early OA -> femoral head subluxates from acetabulum
- Erosion of joint margins (eg dorsal acetabular rim)
- Pain and disuse -> poor muscle development around hip -> further destabilisation
Give the 2 presentations of hip dysplasia
- Young dogs (<1yr old) which suffer pain due to joint laxity and joint inflammation
- Older dogs with chronic OA of hip secondary to hip dysplasia
Give the clinical signs of hip dysplasia in younger dogs
- Unilateral/bilateral HL lameness
- ‘Bunny-hopping’
- Reluctance to exercise
- Pain upon hip extension/flexion
- Positive Ortolani test (ie hip luxation)
Give the clinical signs of hip dysplasia in adult dogs
- Stiffness after rest/exercise
- Exercise intolerance
- ‘Bunny hopping’
- Usually bilateral
- Pain upon joint manipulation and reduced ROM
How do you diagnose hip dysplasia?
- History + clinical signs + radiography
- Radiography can be static (VD, frog-legged or latromedial) or dynamic (not common in UK)
Which radiographic view is required for the BVA Kennel Club Control Scheme for hip dysplasia?
VD with the HLs extended such that the femurs are parallel
Give some primary radiographic changes of the hip joint with hip dysplasia
- Wide joint space with medial divergence
- Centre of femoral head lying on/lateral to dorsal acetabular rim
- Coxa valga (>150 degree angle of femoral shaft to neck)
Give some secondary radiographic changes of the hip joint with hip dysplasia
- New bone formation around femoral neck within acetabular fossa
- Remodelling of cranial acetabular rim