SA Orthopaedics Flashcards
What is geometric distortion in radiography?
Occurs if structure is towards edge of collimated area or not truly parallel to film
Artefactually short/long etc
Limitations of radiography?
Oblique projections can create apparent artifactual lesions
Poor soft tissue contrast resolution
What is serial radiography?
Repeated radiographs over time
To monitor progression of disease etc
Can be useful if diagnosis is uncertain
What are the radiographic (Rontgen) signs?
Number Size Shape Location Opacity
What soft tissue changes can be seen on radiographs and what can cause them?
Focal atrophy - chronic lameness, neurogenic, fibrosis/scarring
Focal swelling - trauma, abscess/seroma, granuloma, neoplasia
Diffuse swelling - oedema, cellulitis/vasculitis, diffuse neoplasia
Reduction in opacity of bone on radiographs: when is this apparent? Causes?
May be artefactual - compare to soft tissue
30-60% mineral loss required to be apparent
Minimum 7 days to be apparent
Focal loss easier to detect
Generalised - systemic disease e.g. nutritional secondary HPTH
Focal - neoplasia, osteomyelitis
What types of radiographic focal bone loss (lysis) are there?
Geographic = fairly even homogenous widespread loss of opacity - less aggressive
Moth-eaten = coalescing areas of heterogenous lysis
Permeative - more aggressive
How do aggressive bone lesions appear on radiographs?
Long transition zone
Active periosteal reaction
Destruction of cortical integrity
Soft tissue swelling
What to assess about joints on radiography?
Soft tissue swelling Joint space width Subchondral bone opacity Osteophyte/enthesiophytes Periarticular mineralisation
NB can’t see cartilage (not ST opacity)
In which joint can you distinguish between periarticular swelling around the joint and a joint effusion?
Stifle
Because adjacent fat provides contrast
What may be seen on radiography with OA?
Soft tissue swelling/effusion
Periarticular new bone at predictable sites
Subchondral sclerosis
Narrowed joint space
What predilection sites are there for osteochondrosis?
Caudal aspect of humerus head
Medial part of humeral condyle
Lateral femoral condyle
Medial trochlear ridge of talus
What predilection sites are there for osteoarthritis?
Proximal humerus
Distal radius/ulna
Distal femur
Proximal tibia
Ultrasound for musculoskeletal system: Which probe to use? What can be assessed?
Linear (high frequency) probe
Muscles, tendons and ligaments clear
Bone surface depicted well
Imaging deep to surface not possible if cortex intact
Hip dysplasia: Aetiopathogenesis?
Large breed dogs/Devon Rex cat
Genotype, bodyweight, nutrition, growth rate
Laxity due to poor soft tissue cover, then OA change as response
Pain as femoral head hits dorsal effective acetabular rim
Normally presents at 7-8mo
Clinical signs “subside” 12-18mos
How to approach the hip to avoid the sciatic nerve?
Cranio-dorsally (avoid lateral and caudal)
Bony landmarks of the hind leg?
Wings of ileum Greater trochanter Tuber ischi Lateral condyle of femur Patella Tibial tuberosity Lateral malleolus Head of metatarsus
Hip dysplasia: 2 groups of presentation?
Immature dogs <12mo: - unilateral/bilateral HL lameness - bunny hopping - reluctance to exercise - pain upon hip extension/flexion - positive Ortolani test - poorly muscled Adult dogs: - mature - stiffness after rest/exercise - bunny hopping - usually bilateral - pain upon joint manipulation and reduced ROM - differentiate from bilateral stifle and lumbosacral disease
Diagnosis of hip dysplasia?
History and clinical signs Radiography: - VD extended/frog legged - lateromedial view - special views - want 50% of femur head in acetabulum - early changes: wide joint space with medial divergence, centre of femoral head lateral to dorsal acetabular edge
Conservative treatment of hip dysplasia: Success rate?
80% success rate but 50% on NSAIDs Analgesia - NSAIDs, amantadine, gabapentin Physiotherapy/hydrotherapy Weight control Frequent short walks
Surgical treatment options for hip dysplasia?
Only if non responsive to conservative management
Young dogs:
- triple pelvic osteotomy (TPO): cut pelvis in 3 places, rotate onto femoral head, add plate (not used anymore)
- juvenile pubic symphisiodesis (JBS): electrocautery/staples to cause thermal arrest of pubic chondrocytes, shortens pubic bones and fixed in pelvis, results in ventrolateral rotation of acetabulum and better congruity, need to diagnose at 14-16 weeks, no effect if performed after 22 weeks
All dogs:
- femoral head and neck excision (FHNE): salvage procedure, <15kg ideally, craniolateral approach to hip, remove all neck and bony spurs, preserve muscle, point patella to sky when cutting, need lots of exercise after surgery
- total hip replacement (THR) (>9 months): best treatment in dogs, contraindicated if chronic systemic illness e.g. skin, maintained on analgesia, expensive (£4500-7000)
Legg-Calve-Perthe’s disease: Which breeds? Aetiology? Pathogenesis? Diagnosis? Treatment?
Small breeds - onset of lameness 4-11mo
Heritable in WHWT and Manchester terriers (autosomal recessive)
Ischaemia of femoral head bone leads to deformity and collapse
Clinical signs:
- mild cases can be sublclinical
- mild intermittent lameness to acute non weight bearing lameness
- pelvic limb muscle atrophy
- pain and crepitus on manipulation of hip
Diagnosis:
- history and clinical signs:
- radiography: frog leg and VD extended, “apple core” focal bone lysis
Treatment:
- surgical best: FHNE/THR
- post op rehab v important
Capital physical fractures: Which animals? Cause? Clinical signs? Diagnosis? Treatment?
Immature animals (4-7mo) Secondary to trauma Pain upon hip manipulation Diagnosis: - history - clinical signs - radiography Treatment: - three diverging/parallel K or arthrodesis wires - craniolateral or dorsal approach to hip
Coxofemoral luxation: Cause? Which animals? Which direction? Clinical signs? Diagnosis?
Following major trauma e.g. RTA
Usually >12mo
Usually craniodorsal
Clinical signs:
- leg carried in flexion, stifle out, hock in (CD luxation)
- greater trochanter more prominent (look for asymmetry)
- assess triangle between TI, GT and iliac crest
Diagnosis:
- history and clinical signs
- radiography: VD and lateral
Treatment:
- closed reduction (initially) unless HD or avulsion fracture of femoral head, only really for cranio-dorsal
- if re-luxation occurs then open reduction and stabilisation
Closed reduction for coxofemoral luxation: Criteria? Technique?
Within 48h of injury
GA and tie dog to table
Take post-op rads to ensure reduction
Post reduction place in (Ehmer sling) and cage rest for 7-10 days
Keep in surgery if worried
Relaxation due to haematoma or fragments in acetabulum
Open reduction and stabilisation of coxofemoral luxation: Technique?
Craniolateral approach to hip
Remove haematoma and bone fragments from acetabulum and lavage
Replace femoral head with caudal traction of femur
Suture joint capsule
Keep in place by augmenting joint capsule
Function of cranial cruciate ligament?
Prevents tibia moving forwards
CCL rupture: Aetiology?
Aetiology unknown and controversial - trauma least common - degeneration in older dogs (+minor trauma) or predisposed breeds (Lab, terriers) - young large breed dogs Disease related to: - increased collagen metabolism in CCLs in predisposed breeds - increased joint laxity - narrowed intercondylar notches - sloping angle of tibial plateau - immune mediated disease
What makes up the CCL?
Craniomedial band - taut in flexion and extension
Caudolateral band - taut in extension only
Craniomedial band ruptures first = partial tear
Partial tear: positive cranial drawer in flexion, but not in extension as caudo-lateral band intact
CCL rupture clinical signs?
Chronic/acute onset hindlimb lameness
Leg carried flexed or “toe touching”
Stifle effusion (patellar ligament not pencil like)
Medial buttress and OA - chronic
Tibial compression test/cranial drawer test
Diagnosis of CCL rupture?
Clinical exam and history
Radiographs - ML and CrCd
Arthrocentesis - reduced viscosity, increased volume
Conservative treatment for CCL rupture?
Dogs <15kg
Restricted exercise and analgesia for 6-8 weeks
85% will have satisfactory function
Surgical treatments for CCL rupture? Aftercare? Complications?
Intracapsular - OTT
Extracapsular - e.g. lateral fabellotibial nylon sutures
Periarticular - TPLO, TTA
Aftercare:
- re-examine at 4-6 weeks
- progress x rays for osteotomies at 8 weeks
Complications:
- infection
- meniscal tears
Meniscal injury: When happen? Treatment?
At surgery or late meniscal injury
Mostly medial
May respond to conservative management for 4-6 weeks
Surgical removal if persistent lameness
Patellar luxation: Aetiology?
Congenital/developmental or traumatic Medial > lateral Toy breeds/large breeds more common? Cats often asymptomatic Due to developmental malalignment of quadriceps complex
Grading degrees of patella luxation?
1: Intermittent patellar luxation, reduction immediate
2: Frequent luxation, reduction not always immediate
3: Permanent luxation, reduction possible but reluxates
4: Permanent luxation but reduction not possible
Diagnosis of patellar luxation? Treatment?
History and clinical signs - skipping lameness Radiography Conservative treatment: - if none or intermittent clinical signs - restricted, controlled exercise - NSAIDs Surgical treatment: - if recurrent clinical signs, > grade 2 - restore normal alignment of quadriceps mechanism by a combination of reinforcement of lateral retinaculum, release of medial retinaculum, deepening trochlear groove and transposition of tibial tuberosity
Stifle osteochondrosis: How common? Where? Which animals? Clinical signs? Diagnosis?
Not very common Lateral/medial femoral condyle (articular surface) Breed predisposition - labs Male > females OCD if joint mouse Clinical signs: - lameness from 5mo - bilateral crouching gait - joint effusion and discomfort on palpation Diagnosis: - history and clinical signs - radiography: CrCd most used but can see flattening on ML view
Rupture of collateral ligaments of the stifle: Diagnosis? Treatment?
Alone or in combo with CCL rupture
Medial or lateral
Diagnosis:
- abnormal joint movement in medial or lateral direction
- stressed radiographs (check contralateral limb for normality)
Treatment:
- parapatellar approach to side affected
- primary repair of ligament and repair protected by screws and washers at insertion sites
Multiple ligament injuries of the stifle: Aetiology? Diagnosis? Treatment?
Aetiology: - uncommon injuries usually working dogs Diagnosis: - careful clinical examination - stress radiography Treatment: - repair of CCL, collateral ligament(s), removal of damaged meniscus and joint capsule- good prognosis but don’t underestimate repair!! - TAESF
Multiple stifle ligament injuries in the cat: Aetiology and treatment?
Aetiology:
- usually in association with CCL rupture
- meniscal injuries
Treatment similar to dogs:
- transarticular pin across stifle joint for 4 weeks
- TAESF
Treatment for foot fractures? Complications?
Single: external coaptation
Multiple: need internal fixation (plates/wires)
Complications:
- extensive soft tissue injuries: check viability
- synostosis between bones: painful
Interphalangeal luxations (“Sprung toe”): Which breed? Which joint? Treatment?
Commonly seen in greyhounds Mainly proximal interphalangeal Treatment: - reduce and suture collateral ligaments with wire sutures - small ESF - toe amputation
Toe amputation: indications? How?
Single digit amp well tolerated
Indications: severe luxations/fracture/neoplasia
Y shaped incision - preserve pad
OC and OCD of the tarsus?
Common cause of hindlimb lameness in large breed dogs
Medial or lateral trochlear ridge of talus
Very straight conformation and bilateral effusion
Rads- flattening of medial trochlear ridge of talus
Surgical treatment- best option
Tarsus fractures?
Central tarsal bone: - dorsal slab fracture - best treatment is lag screws Calcaneus: - avulsion fractures
Talocrural instability: Causes? Treatment?
Damage to lateral/medial collateral ligaments
Malleolar fracture
Surgical treatment?
If fails then pantarsal arthrodesis
Open luxations/shearing injuries of the tarsus: Treatment?
Extensive wound lavage with sterile saline
Stability achieved with external fixator
May need graft or heal by second intention healing
Calcanealquartal instability of the stifle: Causes? Diagnosis? Treatment?
Trauma or degenerative (shelties/collies)
Rupture degeneration of plantar ligament
Plantigrade stance
Diagnosis - history and clinical signs and stressed views
Calcaneoquartal arthrodesis
Principles for arthrodesis of tarsus?
Dorsal approach to tarsus
Expose joint cavity and all joint levels
Use air driven burr to remove articular cartialge
Bone graft (autogenous from proximal humerus/corticocancellous, ilium in cats or DBM)
Place custom made plate over all joint
Post op:
- gutter splint/cast for 6-12 weeks then re-radiograph
- check weekly
- strict rest
- analgesia
Tarsus achilles tendon rupture?
Traumatic
Gastrocnemius enthesiopathy in Dobermans: middle aged, usually bilateral, acute or gradual onset, SDF usually ok, toe clenching
SDFT over top of calcaenus
Complete rupture inc SDFT - plantigrade stance
Treatment:
- plantarolateral approach
- exposed end of tendon with locking loop/three loop pulleys
- place hock in extension with bone screw
- cast for 6 weeks
- restrict exercise
What must you initially assess/do with a pelvic fracture?
ABC Control haemorrhage if present Fluids and shock therapy Check for thoracic injuries Analgesia - opioids, NSAIDs Assess urinary tract Neuro exam Assess function of pelvic nerve - anal/perineal reflex
